evaluation of the amount of apically extruded debris using different root canal instrumentation...

Evaluation of the amount of apically

extruded debris using different root canal

instrumentation systems

A thesis submitted to the council of the College of Dentistry at

the University of Al-Mustansiriyah, in partial fulfillment of

the requirements for the degree of Master of Science in

Conservative Dentistry

By

Hashim Moeen Hussein

B.D.S.

Supervised by

Assistant Prof. Dr. Iman Mohammed Al-Zaka

B.D.S., M. Sc.

September/ 2013 Shawwal/ 1434

To the spirit of my dear brother

To my precious Mother & Father

To my lovely Athraa

To my sweet daughters

Retaj & Fatima

Hashim….

Dedication

I

Acknowledgement

First of all, I would like to thank almighty ALLAH for inspiring me the

energy, patience and strength to accomplish this work. A special peace to our

messenger Mohammed (peace be upon him).

My sincere appreciation goes to Assistant Prof. Dr. Hikmet Abd-Alraheem

Al-Gharrawi, Dean of the college of Dentistry, University of Al-Mustansiriyah, for

continuously supporting the postgraduate students.

My deep appreciation goes to Assistant Prof. Dr. Ammar Atta-Allah Ali

Alsa'ady, Head of Department of Conservative Dentistry at Al-Mustansiriyah

University, for his support and generous help.

My sincere gratitude and deepest respect goes to my supervisor, Assistant

Professor Dr. Iman Mohammed Al-Zaka, for her guidance, kindness, high ethics,

scientific support and continuous helpful advices throughout my study, her effort was

deeply appreciated.

I am highly indebted to Professor Dr. Jamal Aziz Mehdi, for his valuable

advices, support and continuous assistance.

My grateful thanks goes to Assistant Prof. Dr. Hayder Hamed Abed, for his

general assistance during my study.

Deep thanks and appreciations to the Committee of postgraduate studies in

the Department of Conservative Dentistry, for their scientific support throughout the

clinical sessions and for their continuous follow up.

Thanks to Dr. Montadher Saoudi and Dr. Noor Aldiin Ali, for their

continuous helps during the period of my study. My thanks and appreciation to all the

postgraduate colleagues in the Department of Conservative Dentistry, for their

cooperation throughout the study.

https://www.facebook.com/montadher.saoudi

II

Abstract

Various kinds of hand-held, rotary or reciprocating instruments and

techniques are used for mechanical preparation of the canal during root canal

treatments. These instruments and techniques may produce and push debris out of the

canals. The purpose of this study was to evaluate the amount of apically extruded debris

by using 5 types of nickel–titanium endodontic instruments (Hand ProTaper, Rotary

ProTaper, Rotary Mtwo, RECIPROC and WaveOne).

Seventy-five freshly extracted human mandibular premolar teeth were used

in this study. All teeth were shortened to a length of 14mm. The pre-weighted

collecting vial was inserted inside a second glass bottle (flask). Then, the root was

inserted inside rubber stopper (in the center) of vial. After that, the flask was coated

from the external surface with rubber dam material, then a vented needle (25-gauge)

was inserted through rubber stopper. The roots were divided randomly into 5 groups,

each group contained 15 samples:

Group I was prepared by hand ProTaper system (Hand technique).

Group II was prepared by rotary ProTaper system (Full rotary technique).

Group III was prepared by rotary Mtwo system (Full rotary technique).

Group IV was prepared by single file RECIPROC system (Reciprocating

technique).

Group V was prepared by single file WaveOne system (Reciprocating technique).

After each file size of the (hand and rotary files) or after three in-and-out

movement of the (reciprocating files), 1ml of distilled water was used. Canal patency

remained patent with K-file size 15. Debris extruded from apical foramen, was

collected in a collecting glass vial. Then at the end of canal preparation, collecting glass

vial was dried using an oven at 110° C and was checked every half hour until the vial

appears dry, and then placed in desiccator for complete drying. Three consecutive

weights were obtained for each vial, and the mean value was calculated. The difference

III

between the weights of vial (pre-weight and post-weight) represented the weight of

debris extruded from apical foramen during canal preparation.

The data obtained were analyzed statistically using ANOVA and LSD tests.

The results showed that all groups induced extrusion of debris, Mtwo group (III) has

statistically the lowest mean value of apically extruded debris in comparing with all

other groups, followed by rotary ProTaper (II), Hand ProTaper (I), and WaveOne (V)

groups respectively. While the RECIPROC group (IV) has statistically highest mean

value. Reciprocating instruments produced significantly more debris than hand and full

rotary instruments.

IV

List of Contents

Subject Page

No. Acknowledgement I

Abstract II

List of Contents IV

List of Tables VII

List of Figures VIII

List of Abbreviations XI

Introduction 1

Aim of the study 3

Chapter One - Review of Literature 1.1. Cleaning and shaping 4

1.2. History of root canal preparation 4

1.3. NiTi endodontic instruments 7

1.3.1. Advanced NiTi alloy 8

1.4. Design and features of NiTi endodontic instruments 9

1.4.1. Tip 9

1.4.2. Taper 10

1.4.3. Flute 11

1.4.4. Helical angle 12

1.4.5. Pitch 12

1.4.6. Rake angle 13

1.4.7. Radial land 14

1.4.8. Cutting edge 15

1.5. Classification of root canal preparation systems 15

1.6. Full rotary NiTi instruments 16

1.6.1. ProTaper file system 17

1.6.1.1. ProTaper geometries 19

1.6.1.2. Design features of ProTaper system 22

A. Multiple tapers 22

B. Non-cutting modified guiding tip 23

C. Convex triangular cross-section with convex cutting edges 23

D. Helical angle and pitch 24

V

1.6.1.3. Guidelines for using ProTaper system 24

1.6.1.4. Method to use ProTaper system 25

1.6.2. Mtwo file system 25

1.6.2.1. Mtwo geometry 25

1.6.2.2. Design features of Mtwo system 26

A. Tapering 26

B. Length 27

C. Cross section 28

D. Non-cutting tip end 28

E. Helical angle 29

1.6.2.3. Methods to use rotary Mtwo system 30

A. Motion 30

B. Sequences 30

1.7. Reciprocating NiTi instruments 32

1.7.1. Rotation VS. Reciprocation 32

1.7.2. RECIPROC file system 33

1.7.2.1. Design features of RECIPROC files system 35

1.7.2.2. Single file / Single use concept 36

1.7.2.3. File selection 36

1.7.2.4. Shaping technique 37

1.7.3. WaveOne file system 39

1.7.3.1. Design features of WaveOne files system 40

1.7.3.2. Reciprocation movement 41

1.7.3.3. Single file / Single use concept 43

1.7.3.4. File selection 43

1.7.3.5. Shaping technique 44

1.8. Root canal instrumentation techniques 46

1.8.1. Step-down technique 47

1.8.2. Balanced force technique 47

1.9. Apically extruded debris in endodontics 48

Chapter Two - Materials and Methods 2.1. Materials and Equipment 56

2.1.1. Materials 56

2.1.2. Instruments 58

2.1.3. Equipment 58

2.2. Methods 60

2.2.1. Sample selection 60

VI

2.2.2. Sample preparation 61

2.2.3. Sample grouping 62

2.2.4. Method of sample fixation and debris collection 62

2.2.5. Preparation of canals 65

2.2.6. Collection of debris and storage of vials 69

2.3. Statistical analysis 72

Chapter Three-Results Results 73

Chapter Four-Discussion Discussion 78

4.1. Apically extruded debris of Mtwo and other groups 80

4.2. Apically extruded debris of hand and rotary ProTaper 82

4.3. Apically extruded debris of full rotary and reciprocating systems 83

4.4. Apically extruded debris of RECIPROC and WaveOne 84

Chapter Five-Conclusions and Suggestions Conclusions 86

Suggestions 87

References References 88

Appendices Appendices 104

الخالصة

VII

List of Tables

Table

No.

Table title Page

No.

1-1 Design specifications of some rotary NiTi instruments 18

1-2 Design specifications of rotary ProTaper NiTi instruments 20

1-3 Design specifications of rotary Mtwo NiTi instruments 26

1-4 Design specifications of RECIPROC NiTi instruments 36

1-5 Design specifications of WaveOne NiTi instruments 41

3-1 The amount of apically extruded debris for all samples (in mg) 73

3-2 The mean values of apically extruded debris (in mg) and SD for

all groups

74

3-3 ANOVA test for mean of apically extruded debris among groups 75

3-4 LSD test for multiple comparison between groups 76

VIII

List of Figures

Figure

No.

Title Page

No. 1-1 Endodontic Beutelrock-bur in a handpiece with a flexible angle

from 1912

5

1-2 (Left) Cursor-handpiece (W&H) from 1928

(Right) Racer-handpiece (W&H) from 1959

6

1-3 Two types of root canal instrument tips 10

1-4 Tapering of root canal instruments 11

1-5 (A) Grinding the cutting part of rotary NiTi root canal instruments

(B) Elements of the cutting part of root canal instruments

11

1-6 Comparison of a file with constant helical angle (top) and one

with variable helical angle (bottom)

12

1-7 Schematic illustration of the tool angles in the case of positive and

negative rake angles

13

1-8 Radial land (arrow) 14

1-9 (A) Radial-landed instrument cross section

(B) Non-landed instrument cross section

15

1-10 Hand ProTaper files set 19

1-11 Rotary ProTaper files set 19

1-12 SX ProTaper file 20

1-13 S1 and S2 ProTaper files 21

1-14 The finishing ProTaper files 22

1-15 Non-cutting modified guiding tip of ProTaper file (SEM, x 50) 23

1-16 Convex triangular cross-section with convex cutting edges of

ProTaper file (SEM, x 200)

23

1-17 ProTaper file (Pitch and Helical angle) 24

1-18 Mtwo instruments, basic sequence and additional instruments 26

1-19 Mtwo basic sequence with working part 16mm and 21mm 27

1-20 (A) Reduced cross-section of larger Mtwo instrument

(B) Mtwo instrument cross-section (SEM, x 170)

28

1-21 SEM image of the non-cutting tip of Mtwo instrument (SEM, x

320)

28

1-22 SEM image of an Mtwo size 25 taper .06 in lateral view; the

helical angle increases from apex to crown (SEM, x 50)

29

IX

1-23 Mtwo motion 30

1-24 (A) Mtwo basic sequences

(B) Mtwo additional sequences

31

1-25 RECIPROC instruments (R25, R40 and R50) 34

1-26 VDW. SILVER® RECIPROC® 34

1-27 (A) Non-cutting tip of RECIPROC file

(B) RECIPROC cross-section

35

1-28 Selection of the appropriate RECIPROC instrument 37

1-29 Consequences of root canal preparation with RECIPROC file (left

to right)

38

1-30 The Small, Primary and Large WaveOne files 39

1-31 Two different cross-sections on a single WaveOne file 40

1-32 The variable pitch flutes along the length of WaveOne instrument 41

1-33 Non-cutting modified guiding tip of WaveOne file 41

1-34 The e3 motor 42

1-35 Three engaging/disengaging cutting cycles of WaveOne file 43

2-1 Hand ProTaper file kit 57

2-2 Rotary ProTaper file kit 57

2-3 Mtwo file kit 57

2-4 RECIPROC file kit 57

2-5 WaveOne file kit 57

2-6 Glass flask 59

2-7 Collecting glass vial 59

2-8 Endo-Mate DT motor 59

2-9 SILVER® RECEEPROC® motor 59

2-10 WaveOneTM motor 59

2-11 Some of materials, instruments, and equipment used in the study 60

2-12 (A) Determining the length of the root

(B) Sectioning of the root

(C) Length of the root with digital caliper

61

2-13 Sample organization into five groups 62

2-14 Insertion of the flask inside a hole in a rectangular wood base 63

2-15 Insertion of the vial inside flask 63

2-16 Root fixation in the center of rubber stopper 63

2-17 Root and stopper were fitted in the glass vial 64

2-18 Glass flask hold vial and root (drawing illustration)

A, root. B, glass vial. C, glass flask

64

X

2-19 Coating the flask with rubber dam material, and insertion of the

needle through the rubber stopper

65

2-20 (A) Instrumentation of the canal by hand ProTaper files

(B) Hand ProTaper set.

66

2-21 (A) Instrumentation of the canal by rotary ProTaper file

(B) Rotary ProTaper set.

67

2-22 (A) Instrumentation of the canal by Mtwo files

(B) Rotary Mtwo set.

68

2-23 (A) Instrumentation of the canal by RECEPROC R40 file.

(B) R40 file.

68

2-24 (A) Instrumentation of the canal by large WaveOne file.

(B) Large WaveOne file (size 40).

69

2-25 Washing the apex of the root with distilled water 70

2-26 Samples inside oven 70

2-27 Dry debris collected in a glass vial 71

2-28 Placement of vials in the desiccator 71

2-29 Sensitive electronic balance 71

3-1 Bar chart graph for mean of apically extruded debris among five

groups.

75

XI

List of Abbreviations

Ag-Ab Antigen-antibody

AED Apically extruded debris

CaCl2 Calcium chloride

DW Distilled water

HPT Hand ProTaper

HA Helical angle

ISO International Standards Organization

LSD Least significant difference test

MAF Master apical file

Max. Maximum

M-wire Memory shape wire

Min. Minimum

Ncm Newton centimeter

NiTi Nickel-Titanium

NS Non-significant

No. Number

ANOVA One-way analysis of variance

P-value Probability value

PT ProTaper

RA Rake angle

Rpm Revolution per minute

RPT Rotary ProTaper

SEM Scanning electronic microscope

S Significant

# Size

NaOCl Sodium hypochlorite

S.S Stainless steel

SD Standard deviation

SE Standard error

VHS Very high significant

WL Working length

Introduction &

Aims of the study

1

Introduction

Root canal preparation is one of the most important stages in endodontic

treatment. It includes mechanical cleansing by instruments and the use of irrigants.

During the procedure, there is always the possibility of pulp tissue fragments, dentine

chips, necrotic tissue, microorganisms, and intracanal irrigants being extruded beyond

the apical foramen even when the working length is controlled. The extruded material

referred to as ‘worm of necrotic debris’ has been related to periapical inflammation and

postoperative flare-ups. A thorough control of the working length may decrease this

risk, but nevertheless any extrusion of debris may potentially cause postoperative

complications such as flare-ups (Seltzer and Naidorf, 1985; Lambrianidis et al.,

2001).

Flare-up is described as the occurrence of pain, swelling, or the combination

of both during or after completion of root canal therapy. This phenomenon is also called

interappointment emergency. Occurrence of inter-appointment flare-up is extremely

undesirable for patients; proper measures should be employed for reducing apical

extrusion of infected debris (Siqueira et al., 2004).

During the last decade, root canal preparations with rotary nickel–titanium

instruments have become popular. Because canal preparation with rotary nickel–

titanium systems remains significantly more centered in the root canal, this results in

less transport of materials than hand instruments filing with stainless steel files (Lopez

et al., 2008).

In the progressive ProTaper system, the shaping files have an increasing

taper from tip to coronal, whereas the finishing files have a decreasing taper. It has

been claimed that the increasing taper instruments have enhanced flexibility in the

middle region and at the tip, and that the decreasing taper instruments provide larger

taper in the important apical region but make them stiff (Bergmans et al., 2003).

Mtwo system is another full rotary nickel–titanium system. It has basic

sequence and shaping sequence. Mtwo is unlike other modern nickel–titanium systems,

2

Mtwo is used with “single-length technique”, and all the instruments are taken to the

full working length (Sonntag et al., 2007). As entire canal length is approached at the

same time, this technique has also been called “simultaneous technique” (Malagnino

et al., 2006).

Recently, reciprocating system was introduced. RECIPROC file and

WaveOne file are able to completely prepare root canals with only one instrument.

These files are made of a special nickel–titanium alloy called M-wire that is created by

an innovative thermal treatment process. The benefits of this M-wire alloy are

increased flexibility and improved resistance to cyclic fatigue of the instruments

(Gutmann and Gao, 2012). The RECIPROC and WaveOne files are used in a

reciprocal motion that requires special automated devices (Yoo and Cho, 2012).

Many researchers found that instrumentation techniques produce some

debris extrusion (McKendry, 1990; Al-Omari and Dummer, 1995; Azar and

Ebrahimi, 2005; Nazari and MirMotalibi, 2006). This can induce inflammation

within the periapical area; therefore, instrumentation technique that causes less

extrusion of debris is more desirable (Adl et al., 2009).

3

Aims of the study

The objective of this study is to measure and compare the amount of apically

extruded debris by using different instrumentation systems:

1. Hand ProTaper file (Hand system).

2. Rotary ProTaper file (Full rotary system).

3. Rotary Mtwo (Full rotary system).

4. RECIPROC file (Reciprocating system).

5. WaveOne file (Reciprocating system).

Chapter One

Review of

Literature

Review of Literature Chapter One

4

1.1. Cleaning and shaping

Root canal shaping is one of the most important steps in canal treatment. It

is essential in determining the efficacy of all subsequent procedures, including

chemical disinfection and root canal obturation (Hulsmann et al., 2005). However,

even if this stage is adversely influenced by the highly variable root canal anatomy

(Peters et al., 2003), it aims to achieve complete removal of the vital or necrotic tissue

to create sufficient space for irrigation (Schilder, 1974; Hulsmann et al., 2005).

Furthermore, shaping tends to preserve the integrity and location of the canal and apical

anatomy in preparation for an adequate filling (Wu et al., 2000; Moore et al., 2009).

The avoidance of both iatrogenic damage to the root canal structure and further

irritation of the periradicular tissue is demanding for all the newest instrumentation

techniques. Maintaining the original canal shape using a less invasive approach is

associated with better endodontic outcomes (Hulsmann et al., 2005; Pak and White,

2011).

The ideal prepared root canal must have a continuously tapering funnel shape

that preserves the original anatomy with the smallest diameter at the end point and the

largest at the orifice providing adequate canal shape to fill the canal (Schilder, 1974;

Ingle et al., 2008). Shaping the canal is the most time-consuming and difficult factor

of root canal therapy. Many techniques, devices, and instruments such as stainless steel

(S.S) hand instruments or nickel-titanium (NiTi) rotary instruments have been

introduced to produce the appropriate root canal preparation (Yoo and Cho, 2012).

1.2. History of root canal preparation

In a survey of endodontic instrumentation up to 1800, Lilley in 1976

concluded that at the end of the 18th century ‘only primitive hand instruments and

excavators, some iron cauter instruments and only very few thin and flexible

instruments for endodontic treatment had been available’. Indeed, Edward Maynard

has been credited with the development of the first endodontic hand instruments.

Notching a round wire (in the beginning watch springs, later piano wires), Edward


5

created small needles for extirpation of pulp tissue (Grossman, 1976; Bellizzi and

Cruse, 1980). In 1852, Arthur used small files for root canal enlargement (Bellizzi and

Cruse, 1980). Textbooks in the middle of the 19th century recommended that root

canals should be enlarged with broaches: ‘But the best method of forming these canals

is with a three- or four-sided broach. This instrument is employed to enlarge the canal,

and give it a regular shape’ (Hulsmann, 1996).

In 1885 the Gates Glidden (GG) drill and in 1915 the K-file were introduced.

Although standardization of instruments had been proposed in 1929 by Trebitsch and

again by Ingle in 1958, International Standards Organization (ISO) specifications for

endodontic instruments were not published before 1974 (Hulsmann, 1996).

The first description of the use of rotary devices seems to have been by

Oltramare. He reported the use of fine needles with a rectangular cross-section, which

could be mounted into a dental handpiece. These needles were passively introduced

into the root canal to the apical foramen and then the rotation started. He claimed that

usually the pulp stump was removed immediately from the root canal and advocated

the use of only thin needles in curved root canals to avoid instrument fractures

(Hulsmann et al., 2005).

In 1889 William H. Rollins developed the first endodontic handpiece for

automated root canal preparation. He used specially designed needles, which were

mounted into a dental handpiece with a 360° rotation. To avoid instrument fractures

rotational speed was limited to 100 revolution per minute (rpm). In the following years

a variety of rotary systems were developed and marketed using similar principles (Fig.

1-1) (Hulsmann et al., 2005).

Fig. 1-1: Endodontic Beutelrock-bur in a handpiece with a flexible angle from

1912 (Hulsmann, 2000).


6

In 1928, the ‘Cursor filing contra-angle’ was developed by the Austrian

company W&H (Burmoos, Austria). This handpiece created a combined rotational and

vertical motion of the file (Fig. 1-2). Finally, endodontic handpieces became popular

in Europe with the marketing of the Racer-handpiece (W&H) in 1958 (Fig. 1-2) and

the Giromatic (MicroMega, Besancon, France) in 1964. The Racer handpiece worked

with a vertical motion, the Giromatic with a reciprocal 90° rotation. Further endodontic

handpieces such as the Endolift (Kerr, Karlsruhe, Germany) with a combined vertical

and 90° rotational motion and similar devices were marketed during this period of

conventional endodontic handpieces. All these devices worked with limited, rotation

and/or a rigid up and down motion of the instrument, which were all made from S.S.

(Hulsmann, 1996; Hulsmann, 2000).

Fig. 1-2: (A) Cursor-handpiece (W&H) from 1928 (Hulsmann, 2000).

(B) Racer-handpiece (W&H) from 1959 (Hulsmann, 2000).

A period of modified endodontic handpieces began with the introduction of

the Canal Finder System (distributed by S.E.T., Grobenzell, Germany) by Levy (Levy,

1984).


7

1.3. NiTi endodontic instruments

Endodontic instruments were originally made from carbon steel. Later on

S.S employed and since 1988 endodontic instruments fabricated from NiTi, but

because of extreme flexibility of NiTi, they are not designed for initial negotiation of

the root canal. On the other hand, the greater stiffness of S.S instruments allowed them

to be used for path finding and to establish canal patency (Beer et al., 2006).

When using the S.S files, occurrence of procedural errors cannot be avoided

specially in case of curved canals. Deviation from the original shape, ledge formation,

zipping, stripping and perforations are the common problems which are seen in such

cases, but the super elasticity of NiTi alloy allows these instruments to flex more than

the S.S instruments before exceeding their elastic limit, thereby allowing canal

preparation with minimal procedural errors (Garge and Garge, 2010).

NiTi was developed by Buchler in 1963. NiTi is also known as NiTiNOL

(Nickel-Titanium Noval Ordinance Laboratory) in Silver Springs, Maryland, US. In

endodontics commonly used NiTi alloys are called 55 NiTiNOL (55% weight Ni and

45% weight Ti) and 60 NiTiNOL (60% weight Ni and 40% weight Ti). First use of

NiTi in endodontic was reported by Walia et al., in 1988, when a size 15 NiTi file was

made from orthodontic wire and it showed superior flexibility and resistance to

torsional fracture, this suggested the use of NiTi files in curved canals.

NiTi is called an exotic metal because it does not conform to the normal rules

of metallurgy. NiTi alloy has special characteristics of superelasticity and shape

memory (Shen et al., 2011). NiTi is characterized as a superelastic alloy, with total

recovery capacity even when deformed up to 8% beyond its elastic capacity. Other

advantages associated with NiTi include its biocompatibility and high resistance to

corrosion (Gavini et al., 2010).

Originally, NiTi endodontic instruments were designed for manual

instrumentation. They have become increasingly recognized as key elements in the

automation of chemicomechanical root canal preparation. The use of NiTi instruments


8

coupled to electric or pneumatic motors has allowed the combination of speed and

quality during endodontic treatments, thus reducing working time and consequently

increasing productivity and comfort for both the operator and the patient (Gavini et

al., 2010).

1.3.1. Advanced NiTi alloy

Possible strategies to increase efficiency and safety of NiTi rotary include an

improvement in the manufacturing process, or the use of new alloys that provide

superior mechanical properties. A new NiTi alloy, termed the M-wireTM (Memory

shape wire) (Dentsply Tulsa Dental Specialties, Tulsa, OK, USA) was developed in

2007. Before the grinding process, the alloy is thermally treated to improve its

properties. The final goal is to produce instruments with greater flexibility and

increased resistance to cyclic fatigue, compared to those constructed from traditional

NiTi alloy (Larsen et al., 2009).

From the practical point of view, NiTi “shape memory metal alloy” can have

three different forms: martensite, stress-induced martensite (superelastic) and

austenite. When the material is in its martensite form, it is soft and ductile, and it can

be easily deformed. Superelastic NiTi is highly elastic (rubber-like), while austenitic

NiTi is quite strong and hard (Bergenholtz et al., 2010).

The transition from the austenitic phase to martensitic phase can occur as

result of temperature and stress, e.g. during root canal preparation, and after the release

of stresses, the metal returns to the austenitic phase, and the file reveal to its original

shape. This phenomenon is called stress-induced thermoelastic transformation. Due to

its pseudoelastic properties, this material can survive deformation without reaching the

elastic limit, thus returning to its original shape (Vaudt et al., 2007). Studies have

shown that M-wire technology significantly improves the resistance to cyclic fatigue

by almost 400% compared to commercially available 25/04 NiTi files (Johnson et al.,

2008).


9

Recently, NiTi rotary instruments made from a NiTi controlled memory

(CM) wire have been introduced. The manufacturer claims that these instruments have

flexibility and fatigue resistance superior to conventional NiTi rotary instruments made

from superelastic wire. These new methods and materials for manufacturing NiTi

instruments may advance the science of endodontic rotary instrumentation (Shen et

al., 2011).

1.4. Design and features of NiTi endodontic instruments

1.4.1. Tip

Tip is the element of the working part that performs the guiding function

(Fig. 1-3). The tip might have a sharp or rounded (bullet-like) configuration, depending

on whether it appears (Hargreaves and Cohen, 2011; Rzhanov and Belyaeva, 2012):

Active.

Passive.

An active tip has cutting edges on its surface, which are made for the removal

of dentine or obturation material from the root canal (Fig. 1-3). Most instruments with

an active tip allow for removal of obturation material during retreatment. One of the

prominent disadvantages of NiTi is the lack of tactile feedback. Therefore instruments

with an active tip require special care when operated because of significant risk of

perforation when deviation from canal axis occur, due to insufficient instrument

flexibility or the presence of obstacles in the root canal (hard obturation material,

separated instrument or ledge) (Rzhanov and Belyaeva, 2012). A passive tip does not

have cutting edges and does not possess cutting properties (Fig. 1-3). A passive tip

reduces the risk of instrument deviation from the canal axis, and as a consequence the

risk of transportation or ledge formation. The majority of NiTi root canal instruments

have passive tips (Bergenholtz et al., 2010; Rzhanov and Belyaeva, 2012).

The cutting part is the prime element of the working section, which has

cutting blades that perform the enlargement of the root canal. All the basic parameters

of the root canal instrument describe its cutting part and determine the pattern of


10

instrument-substrate interaction, instrument behavior in the root canal and the

operation technique (Rzhanov and Belyaeva, 2012).

Fig. 1-3: Two types of root canal instrument tips (Rzhanov and Belyaeva, 2012).

1.4.2. Taper

Taper is described as the amount of file diameter increase per millimeter

along the working surface from the tip toward the file handle. In the past, as an ISO, a

hand file was fluted and tapered at a constant 2% for 16mm. New rotary files

incorporate a wide variation of constant or variable tapers at different lengths of

working surface (Karabucak et al., 2010).

Various tapers exist in all file systems. Most instrument tapers are fixed,

meaning they increase at a standardized, consistent rate from the tip of the file up to

the end of flutes. These fixed taper file systems range from 0.02mm taper to 0.12mm.

Some of the newer instruments have a variable taper built into the instrument. Thus

within a single instrument the taper varies, sometimes starting at a specific taper and

then altering the tapers as it travels the shank so as to improve efficiency in its cutting

(Handysides, 2010). It has been reported that instruments with progressive taper can

shape canals more quickly than constant taper instruments (Fig. 1-4) (Bergmans et al.,

2003).


11

Fig. 1-4: Tapering of root canal instruments (Rzhanov and Belyaeva, 2012).

1.4.3. Flute

The fluting is a specific surface with a certain configuration, which is created

on the working part to impart the cutting ability to the instrument. In general, the fluting

is formed by grinding out a groove of a specific profile onto the cylindrical or conical

NiTi blank - the rod with appropriate diameter (Fig. 1-5). As a result of the grinding

process, adjoining flutes form the cutting blade (Fig. 1-5). The blade is the wedged

element of the cutting instrument, which is used for the substrate penetration and the

chip separation (Rzhanov and Belyaeva, 201 2).

Fig. 1-5: (A) Grinding the cutting part of rotary NiTi root canal instruments

(Rzhanov and Belyaeva, 2012).

(B) Elements of the cutting part of root canal instruments (Rzhanov

and Belyaeva, 2012).


12

1.4.4. Helical angle

It is the angle formed between the blade and the long axes of the instrument.

Variable helical angles (HA) are an important aid to moving debris up and out of the

canal (Fig.1-6) (Kim, 2004). Additionally, a constant HA file is more prone to debris

accumulation. This debris accumulation can lead to the need for increased torque,

which can lead to potential separation (Koch and Brave, 2002).

Fig. 1-6: Comparison of a file with constant helical angle (top) and one with

variable helical angle (bottom) (Kurtzman, 2007).

1.4.5. Pitch

Pitch is the distance between a point on the leading edge and the

corresponding point on the adjacent leading edge, or it may be the distance between

corresponding points within which the pattern is not repeated (Fig. 1-5) (Hargreaves

and Cohen, 2011). It is very important because a constant pitch will work much like a

wood screw and pull you into the tooth. A variable pitch, on the other hand, will

significantly decrease the tendency of the file to get sucked down into the tooth. This

is especially significant when using tapers of 0.06 or greater. Interestingly, it does not

matter how the pitch is varied, as long as it is variable (Koch and Brave, 2002). In

addition, a smaller pitch distance would give more resistance to the file and less cutting

efficiency (Mounce, 2004).


13

1.4.6. Rake angle

The rake angle (RA) can be seen as the angle between the leading edge of a

cutting tool and a perpendicular to the surface being cut. The RA can be negative,

neutral or positive (Bergenholtz et al., 2010).

If the angle formed by the leading edge and the surface to be cut (its tangent)

is obtuse, the RA is said to be positive or cutting (Fig. 1-7). If the angle formed by the

leading edge and the surface to be cut is acute, the RA is said to be negative or scraping

(Fig. 1-7). However, the RA may not be the same as the cutting angle. If the flutes of

the file are symmetric, the RA and the cutting angle are essentially the same. Only

when the flutes are asymmetrical are the cutting angle and RA different. Both angles

may change as the file diameters change and may be different for file sizes

(Hargreaves and Cohen, 2011).

Fig. 1-7: Schematic illustration of the tool angles in the case of positive and

negative rake angles (Bergenholtz et al., 2010).


14

It is well known that the cutting efficiency of a file depends upon the rake

angle of its cutting blades. Since dentine is a dense and resilient material, instruments

having a negative RA are less efficient and require more energy to cut dentine than

files with a positive RA (Wildey et al., 1992). Most endodontic instruments have a

slightly negative or substantially neutral RA. The result is a scraping rather than cutting

action. The ideal RA is slightly positive because an overly positive RA will result in

too actively cutting of dentine and probably threading in (Gambarini, 2000).

1.4.7. Radial land

It's a flat area that is located directly behind the cutting edge of the instrument

(Fig. 1-8). The land touches the canal walls at the periphery of the file and reduces the

tendency of the file to screw into the canal, reduces transportation of the canal, reduces

the progression of microcraks on its circumference, supports the cutting edge; and

limits the depth of cut (Karabucak et al., 2010).

Fig. 1-8: Radial land (arrow) (Hargreaves and Cohen, 2011).

Radial lands on rotary files will increase lateral resistance (torque). Increased

resistance will results in increased torque requirements which is not a good thing for

rotary files as this will elevates the danger of instrument fracture. So the lack of this

area allows the instrument to be sharper and consequently more efficient, in addition

this will results in a decreased thickness of metal (Fig. 1-9). The result of less metal is

a dramatic increase in flexibility. Theoretically, the radial land improves irrigation flow

apically and the movement of debris coronally (Kim, 2004).


15

Fig. 1-9: (A) Radial-landed instrument cross section (Handysides, 2010).

(B) Non-landed instrument cross section (Handysides, 2010).

1.4.8. Cutting edge

The surface with the greatest diameter that follows the groove (where the

flute and land intersect) as it rotates forms the leading (cutting) edge or the blade of the

file (Fig. 1-5). The cutting edge forms and deflects chips from the wall of the canal and

severs or snags soft tissue. Its effectiveness depends on its angle of incidence and

sharpness (Hargreaves and Cohen, 2011).

1.5. Classification of root canal preparation systems

Endodontic instruments for root canal preparation can be divided into six

groups (Hargreaves and Cohen, 2011):

Group I: Manually-operated instruments, such as barbed broaches and K-type and

H-type instruments.

Group II: Low-speed instruments with a latch-type attachment. Typical

instruments in this group are GG burs and Peeso reamers. They are typically used

in the coronal part of the canal and never used in a canal curvature.

Group III: Engine-driven NiTi rotary instruments. They consist of a rotating blade

that can safely be operated in, and adapt itself to, curved root canals. Most engine


16

driven instruments available today belong to this group (e.g. ProFile, ProTaper

(PT), and K3).

Group IV: Engine-driven instruments that adapt themselves three-dimensionally

to the shape of the root canal. Like other NiTi instruments, they adapt to the shape

of the root canal longitudinally but additionally they adapt also to the cross-section

of the root canal. There is currently only one instrument in this group: the self-

adjusting file (SAF) (ReDent-Nova, Raanana).

Group V: Engine-driven reciprocating instruments (e.g. RECEPROC and

WaveOne).

Group VI: Ultrasonic instruments.

1.6. Full rotary NiTi instruments

Rotary NiTi instruments have been shown to prepare the root canal rapidly,

and maintain the canal shape and WL with few aberrations during root canal

preparation (Ayar and Love, 2004).

The major disadvantage associated with their use has always been the

tendency to separate during function without warning in inexperienced hands.

Although the repeated clinical use of NiTi rotary instruments resulted in the reduction

of their cyclic fatigue resistance, clinicians often reuse these instruments because of

financial reasons. The No. of times in which a NiTi rotary instrument can be reused

remains uncertain (Ounsi et al., 2011).

These instruments are generally used in low speed torque control handpiece

with 360° file rotation and rotation rate of 150-350 rpm. However, they differ from one

to another in the cross-sectional geometry, RA, tip design and taper, Table (1-1)


The first NiTi rotary file (1st generation) introduced into North America was

the Lightspeed system. This file, although similar to the S.S Canal Master, changed the

way clinicians thought about performing endodontic procedures. The Lightspeed gives


17

the option of using NiTi rotary instrumentation in addition to (or in place of S.S) hand

files (Wildey and Senia, 1989).

The next generation of rotary files (2nd generation) were those files that had

radial lands. Examples of these files are the Profile, Greater Taper (GT), Quantec, and

K3. All of these files have radial lands, although some have full lands (Profile, GT)

while others (Quantec, K3) have recessed lands. While design differences do exist

between these files, in areas such as pitch and helical angles, the great similarity is the

existence of radial lands (Vaudt et al., 2007).

The third generation of rotary files (3rd generation) were those files with

specific design changes, such as the PT (DENTSPLY Maillefer) and Reamer with

alternating cutting edge (RaCe) (FKG, La Chaux-de-Fonds, Switzerland) (Hargreaves

and Cohen, 2011).

The introduction of a fourth generation rotary file (4th generation) begins with

EndoSequence (Brasseler USA, Savannah, GA). By using alternating contact points,

the file can remain centered without radial lands. The EndoSequence file system has

given clinicians the ability to machine predictable shapes (using constant taper files)

that ultimately leads to synchronicity between the preparation and the master cone fit

(Koch and Brave, 2005).

1.6.1. ProTaper file system

The ProTaper system developed in 2001 by a group of endodontists:

professor Pierre Machtou (University of Paris, France); Dr. Clifford Ruddle (Santa

Barbara, California, the United States); and Professor John West (University of

Washington, Seattle, and the University of Boston, Boston Massachussets, the United

States) in cooperation with Dentsply/Maillefer. Originally, PT instruments are

developed to facilitate instrumentation of difficult, constricted and severely curved

canals. They are designed to cover the range of treatment with only few files. In many

cases only three instruments are needed to complete shaping of the canal (Clauder and

Baumann, 2004).


18

Table (1-1): Design specifications of some rotary NiTi instruments (Hargreaves

and Cohen, 2011).

Instrument

type

Tip sizes Cross section rpm Lengths

LightSpeed 20-130 U-shaped 2500 21, 25, 31mm

ProFile Orifice Shapers (20-80)

ProFile .06 (15-40)

ProFile .04 (15-90)

ProFile .02 (15-45)

Profile Series 29 (13-

100)

U-shaped 150 to 350 21, 25, 31mm

21, 25mm

GT file 20 (.04, .06)

30 (.04, .06, .08)

40 (.04, .06, .08)

U-shaped 300 21, 25, 31mm

HERO 20, 25, 30 (.02, .04, and

.06)

35 to 45 (.02)

Triple helix

(Symmetrical)

300-600 21, 25mm

K3 15-45 (.02)

15-60 (.04 and .06)

Triple helix

(Asymmetrical)

300 to 350 21, 25, 30mm

FlexMaster 15-70 (.02)

15-40 (.04 and .06)

Convex

triangular

280 (150 to

300)

21, 25, 28mm

RaCe 15-60 (.02)

25-35 (.04)

30, 40 (.06)

35 (.08)

40 (.10)

Triangular or

Square

Up to 600

Minimal

axial

force

19mm

25mm

EndoSequence 15-60 (.04)

15-50 (.06)

Triangular 500-600 21, 25, 31mm

Twisted (TF) 25 (.04-.12) Triangular 500 23, 27mm


19

Hand NiTi instruments can also be selected instead of rotary instruments in

teeth with difficult canal anatomy and/or problematic handpiece access. Hand

ProTaper (HPT) (Fig. 1-10) appeared as an alternative NiTi instrument to the rotary

ProTaper (RPT) (Fig. 1-11), embodying the same philosophy, indications, and

sequence, but at a lower cost. The instrumentation is entirely manual, dispensing with

the use of an electric motor. The Hand NiTi instruments are recommended for use in

reaming or “modified balanced forces” motion, differing from the motor-driven NiTi

instruments (Li et al., 2011).

Fig. 1-10: Hand ProTaper files set (DENTSPLY, 2006).

Fig. 1-11: Rotary ProTaper files set (DENTSPLY, 2006).

1.6.1.1. ProTaper geometries

This system has three shaping and five finishing files, Table (1-2). The

auxiliary shaping ProTaper file (SX) has no identification ring on its colored handle

and a shorter overall length of 19mm. SX is available with 14mm of cutting blades,

diameter at tip of instrument (D0) diameter of 0.19mm with partially active tip and

D14 diameter of 1.2mm. At D6, D7, D8 and D9, the cross-sectional diameter increases

from 0.5mm, 0.7mm, 0.9mm and 1.1mm (according to taper: 11%, 14.5%, 17% and


20

19% respectively). The total increase of taper from D0-D9 is defined with nine

different tapers from 3.5% to 19% as compared to the other two shaping files (Ruddle,

2005).

Table (1-2): Design specifications of rotary ProTaper NiTi instruments


No. of instruments/set Cross section Tip sizes/tapers Lengths

3 shaping files (SX, S1, S2)

5 finishing files (F1, F2, F3, F4, F5)

Convex triangular Sx (19/0.035)

S1 (17/0.02)

S2 (20/0.04)

F1 (20/0.07)

F2 (25/0.08)

F3 (30/0.09)

F4 (40/0.06)

F5 (50/0.05)

19, 21, 25mm

The complex file design allows for efficient shaping of the coronal aspects

of the root canal and relocation of canal orifices in the direction of overhanging dentin

area resulting in a straight line access. SX file is designed to replace GG drills where

the diameter of D10 is 1.11 which corresponds to a GG drill No. 4 (Fig. 1-12) (Lumley

et al., 2008).

Fig. 1-12: SX ProTaper file (Rudde, 2001).


21

S1 is designed to prepare the coronal one-third (1/3) of the canal and has an

increasing taper from 2% to 11% on Dl and D14 respectively while S2 has an

increasing taper from 4% on Dl to 11.5% on D14 and designed to enlarge and prepare

the middle 1/3 of the canal (Fig. 1-13). Although, both instruments optimally prepared

the coronal two-thirds (2/3) of the canal, they do progressively enlarge its apical 1/3

because these instruments are already at WL after initial preflaring (Clauder and

Baumann, 2004).

Fig. 1-13: S1 and S2 ProTaper files (Rudde, 2001).

The finishing ProTaper files # 1, 2, and 3 (Fl, F2, and F3) have yellow, red

and blue identification rings on their handles with D0 diameter of 0.20mm, 0.25mm

and 0.30mm respectively. The diameter at the apical few millimeters of the instrument

is greater than that of shaping instrument, making the finishing files stronger (Cheung

et al., 2007).

Finishing files have a fixed taper in the first 3mm from D0 to D3 (i.e. 7%,

8% and 9% for F1, F2 and F3 respectively) (Fig. 1-14). Each file has a decreasing taper

from D4 to D16 which ensure a continuous flexibility within the file and avoids too

large diameter at the shaft area of the instrument, hence reduces the potential for

dangerous taper lock by engaging less dentine and thereby decreasing the chances of

breakage. It also enhances the strength of the files while making them rather stiff

(Bergmans et al., 2003).


22

Fig. 1-14: The finishing ProTaper files (Rudde, 2001).

In ProTaper system, some modification are introduced such as the addition

of two larger files; F4 (finishing ProTaper files # 4) and F5 (finishing ProTaper files #

5) to help in apical preparation of larger canals. F4 had two black rings with ISO 40 tip

size and 6% apical third taper while F5 had two yellow rings and ISO 50 tip size with

5% apical third taper. The body of both files progressively decreasing in taper and that

produce excellent flexibility. These files are produced with a rounded safe tip (West,

2006).

1.6.1.2. Design features of ProTaper system

A. Multiple tapers:

A unique feature of the shaping files is their progressively tapered design

which clinically serves to significantly improve flexibility, cutting efficiency and

typically reduces the No. of recapitulations needed to achieve length, especially in tight

or more curved canals. This design feature allows each shaping file to perform its own

“crown down” work. One of the benefits of a progressively tapered shaping file is that

each instrument engages a smaller zone of dentin, which reduces torsional loads, file

fatigue and the potential for breakage (Ruddle, 2001).


23

B. Non-cutting modified guiding tip:

The tip of these instruments modified by reduction of the transition angle,

making it less aggressive and allowing the instrument to follow canal shape (Fig. 1-15)

(Clauder and Baumann, 2004).

Fig. 1-15: Non-cutting modified guiding tip of ProTaper file (SEM, x 50)


C. Convex triangular cross-section with convex cutting edges:

This design (Fig. 1-16) results in three shape blade edges that improve

cutting ability and tactile sense rather than planning action. It also reduces contact area

between dentine and the cutting blade of the instrument (Hargreaves and Cohen,

2011). As is true with any instrument, increasing its D0 diameter and percentage taper

correspondingly increases its stiffness. To improve flexibility, F3 has a reduced core,

as compared to the other instruments in the series (Ruddle, 2001).

Fig. 1-16: Convex triangular cross-section with convex cutting edges of

ProTaper file (SEM, x 200) (Hargreaves and Cohen, 2011).


24

D. Helical angle and pitch:

ProTaper files have a continuously changing HA and pitch over their 14mm

of cutting blades (Fig. 1-17). Changing the pitch and helical angles over the active

length of blades optimizes its cutting action. Importantly, changing the pitch and helical

angles of a file, in conjunction with a progressively tapered design, prevents each

instrument from inadvertently screwing into the canal (Ruddle, 2001; Martin et al.,

2002).

Fig. 1-17: ProTaper file (Pitch and Helical angle) (Ruddle, 2001).

1.6.1.3. Guidelines for using ProTaper system

There are many guidelines for using ProTaper system (Ruddle, 2001;

Leonardo and De Toledo, 2002; Ruddle, 2005):

Ensuring straight line access.

Check the patency of the canal.

Once WL is confirmed, use each instrument progressively down to the WL.

Always irrigate the canal before engaging the file; use instrument in well irrigated

and lubricated canal.

Clean the instrument directly after use and inspect for the sign of distortion.

ProTaper rotary files should be used at a constant and stable speed between 150 and

350 rpm.

Withdraw the file once the WL is reached.


25

For a better result, RPT shaping files S1, S2 and SX should be used with a brushing

action. RPT files worked with recommended motion clock wise (CW) and very light

apical pressure. Shaping and finishing PT files do not use more than 3-5 seconds

inside canal.

1.6.1.4. Method to use ProTaper system

The ProTaper instruments should be used passively within the canal and their

use may be continued as long as they move easily in an apical direction. To optimize

PT safety, the pencil lead analogy is used to qualify the specific recommended

pressure. The desired pressure on an instrument should be equivalent to the pressure

used when writing with a pencil without breaking the lead. Let the instruments float

like a feather into the canal and allow them to travel apically until they meet light

resistance (Ruddle, 2001).

1.6.2. Mtwo file system

Mtwo rotary NiTi instruments (VDW, Munich, Germany) are another type

of NiTi rotary instruments introduced in the European market since 2003 (Foschi et

al., 2004; Schafer et al., 2006b). These instruments have two cutting edges with

minimal radial contact. Mtwo is the only system with # 10/.04 and # 15/.05 instruments,

and the system has no orifice shaper. Furthermore, in the Mtwo system, the first and

every following instrument is used to full WL, and the ideal speed recommended is

280 rpm (Inan and Gonulol, 2009).

1.6.2.1. Mtwo geometry

The standard set for this system includes four instruments with variable tip

size ranging from # 10 to # 25, and tapers ranging from .04 to .06 (# 10/.04 taper, #

15/.05 taper, # 20/.06 taper, # 25/.06 taper) (Malagnino et al., 2006; Vaudt et al.,

2007).

After this basic sequence, that gives the canal a # 25/.06 shape, the system is

conceived to permit three different approaches to root canal preparation, Table (1-3).


26

The first sequence allows clinicians to achieve enlarged apical diameters using the #

30/.05 taper, 35/.04 taper or 40/.04 taper; the second leads to a .07 taper that can

facilitate vertical condensation of gutta-percha, maintaining a # 25 apical preparation;

and the third implies the use of the Mtwo apical files (Fig. 1-18) (Malagnino et al.,

2006; Vaudt et al., 2007).

Fig. 1-18: Mtwo instruments, basic sequence and additional instruments

(Malagnino et al., 2006).

Table (1-3): Design specifications of rotary Mtwo NiTi instruments (Grande et

al., 2005).

No. of instruments/sets Cross section Tip sizes/tapers Lengths

8 “Italic S” 10/0.04

15/0.05

20/0.06

25/0.06

25/0.07

30/0.05

35/0.04

40/ 0.04

21, 25, 31mm

1.6.2.2. Design features of Mtwo system

A. Tapering:

The colored ring on the handle identifies the size, according to ISO

standards. The No. of grooved rings on the handle identifies the instrument taper; one


27

ring means .04 taper, two rings mean .05 taper, three rings mean .06 taper and four

rings mean .07 taper. The benefit of Mtwo instruments with different tapers

(Malagnino et al., 2006):

1. Early removal of obstructions in the coronal root canal section by using a larger

instrument diameter compared to conventional ISO hand instruments.

2. Fast and efficient preparation of the root canal with only a few instruments.

3. Increased conical shaping for efficient irrigation.

B. Length:

The instruments are available in 21mm, 25 mm, and 31 mm lengths. In the

basic sequence instruments, there are instruments with working part 16mm

(conventional cutting portion of 16 mm) and 21mm (extended cutting portion of 21mm

that don't have any depth markings) as well as the, allowing the instrument to cut in the

coronal portion of the canals, on the cavity access walls, where dentin interferences are

often located, without unnecessarily weakening the tooth substance. Instruments with

a working part of 21 mm do not have any depth markings (Fig. 1-19) (Malagnino et

al, 2006).

Fig. 1-19: Mtwo basic sequence with working part 16mm and 21mm (VDW,

2011).


28

C. Cross section:

The cross-section of Mtwo is an "italic S" with two efficient cutting edges

(Fig. 1-20). In addition, Mtwo is designed with minimum radial contact as well as large

and deep flutes for continuous upwards evacuation of dentine chips. The instrument

core is designed for maximum flexibility, however, without compromising the

instrument's strength. Mtwo instruments with higher ISO size and tapers have a

reduced cross-section (Fig. 1-20). This design ensures the flexibility of the instrument,

facilitates maintenance of the natural canal curvature even for larger apical

preparations (e.g. with an Mtwo 35/.06), no blocking with dentine chips and

instruments (Malagnino et al., 2006; Vaudt et al., 2007).

Fig. 1-20: (A) Reduced cross-section of larger Mtwo instrument (VDW, 2011).

(B) Mtwo instrument cross-section (SEM, x 170) (Plotino et al., 2006).

D. Non-cutting tip end:

The tip of Mtwo instruments is non-cutting allowing the instrument to follow

canal shape (Fig. 1-21) (Malagnino et al., 2006; Schafer et al., 2006a).

Fig. 1-21: SEM image of the non-cutting tip of Mtwo instrument (SEM, x 320)

(Schafer et al., 2006a).


29

E. Helical angle:

The HA of Mtwo instruments is variable and specific for the different files

(Fig. 1-22) (Malagnino et al., 2006; Plotino et al., 2006).

The HA is more open (greater) for the bigger sizes (less flutes for instrument

length), and it decreases for the smaller sizes (more flutes). This determines a greater

cutting efficiency for the bigger sizes and a greater mechanical resistance together with

a tendency to advance in the canal for the smaller ones. The flutes are deeper moving

from the tip to the handle. Moreover, for the bigger file sizes the HA is variable in the

same instruments, it increases from the tip to the handle as does the spiral pitch, while

it is constant for the smaller files, especially for the # 10/.04, the first rotary instrument

that is introduced in the root canal. The variable HA reduces the tendency of the

instrument to be sucked down into the canal (Malagnino et al., 2006; Plotino et al.,

2006).

The tendency to advance spontaneously in the root canal for the smaller

instrument is necessary to progress in the canal during the first phase of the treatment.

The operator should tend towards a pulling-out movement, holding back the instrument

in rotation, enhancing the characteristic of removing debris and the cutting efficiency

(Malagnino et al., 2006).

Fig. 1-22: SEM image of an Mtwo size 25 taper .06 in lateral view; the helical

angle increases from apex to crown (SEM, x 50) (Malagnino et al., 2006).


30

1.6.2.3. Methods to use rotary Mtwo system

A. Motion

Using Mtwo instruments with correct brushing movement, according to the

manufacturer’s instructions, because this helps to reduce stress on the instruments and

leads to optimum preparation results:

1. Insert the rotating instrument into root canal without touching the walls of the canal.

2. Exerting light pressure, allow the instrument to touch the canal wall.

3. Make small, strong/brushing movements (over a few millimeters) in a coronal

direction, without taking the instrument out of the canal (similar to using a

Hedstroem File).

4. Allow the instrument to move apically for few millimeters and then repeat the

movement described under 3. Gradually advance step-by-step towards the apex

with up and down movements. As soon as full WL has been reached, change to the

next instrument in the sequence (Fig. 1-23). Each instrument creates a glide path for

the following instrument.

Fig. 1-23: Mtwo motion ( VDW, 2011).

B. Sequences

The Mtwo NiTi rotary instruments are used at 280-350 rpm. Mtwo

instruments are used in a simultaneous technique without any early coronal

enlargement (Foschi et al., 2004):

1. Glide path has been established with a # 10 K-file.

2. Instruments are each taken to the WL with light apical pressure. As soon as the

clinician feels a binding sensation, clinician pulls the instrument away for 1mm to

http://www.vdw-dental.com/


31

2mm so that it can work passively in a brushing action to selectively remove the

interferences and to advance towards the apex.

3. The instruments are used with a lateral pressing movement in order to obtain a

circumferential cut, and only allowed to rotate at length for few seconds.

The operative sequence suggested for these instruments is a crown down

technique, whereby every NiTi instrument at each step reaches the apex. This means

that this is a technique from the crown to the apex, but it first uses smaller instruments

before using bigger ones, as is done in the step-back technique. The inventor defines

this as a "simultaneous technique" as the entire length of the canal is approached at the

same time (Fig. 1-24) (Foschi et al., 2004; Schafer et al., 2006b). The instrument does

not have to be forced in; as soon as the clinician feels a binding sensation, clinician has

to back the instrument away for 1-2mm so that it can work passively to create the space

necessary to go to the apex. Using the instruments with a lateral pressing movement

(brushing) the tendency to progress automatically in the canal (a sensation of being

"sucked down") increases its efficiency. The high flexibility and fatigue resistance of

the Mtwo instruments permits the use of this approach in severely curved root canals

with an efficient and safe action (Veltri et al., 2005; Schafer et al., 2006b; Grande

et al., 2007).

Fig. 1-24: (A) Mtwo basic sequences (VDW, 2011).

(B) Mtwo additional sequences (VDW, 2011).


32

1.7. Reciprocating NiTi instruments

1.7.1. Rotation VS. Reciprocation

By far, the greatest No. of commercially available files utilized to shape root

canals are manufactured from NiTi and are mechanically driven in continuous rotation.

On the other hand, reciprocation, defined as any repetitive back-and-forth motion, has

been clinically utilized to drive stainless steel files since 1958. Initially, all

reciprocating motors and related handpieces rotated files in large equal angles of 90º

CW and counterclockwise (CCW) rotation. Over time, virtually all reciprocating

systems in the marketplace began to utilize smaller, yet equal, angles of CW/CCW

rotation. Today, the M4 (SybronEndo), Endo-Eze AET (Ultradent), and Endo-Express

(Essential Dental Systems) are examples of reciprocating systems that utilize small,

equal 30º angles of CW/CCW rotation (Ruddle, 2012).

When shaping canals, it should be appreciated that there are both advantages

and disadvantages associated with utilizing continuous rotating vs. a reciprocating

movement. The greater tactile touch and efficiency gained when continuously rotating

NiTi files in smaller-diameter and more curved canals must be balanced with the

inherent risks associated with torque and cyclic fatigue failures. Fortunately, these risks

have been virtually eliminated due to continuous improvement in file designs, NiTi

alloy, and emphasis on sequential glide path management (Berutti et al., 2004).

Compared to reciprocation, continuous rotation utilizing well-designed active NiTi

files requires less inward pressure and improves hauling capacity augering debris out

of a canal (Blum et al., 2003).

On the other hand, a mechanical reciprocating movement has merit because

it somewhat mimics manual movement and reduces the various risks associated with

continuously rotating a file through canal curvatures. However, current motors that

drive reciprocating shaping files through equal forward and reverse angles generally

require multi-file sequences to adequately prepare a canal. Further, systems that utilize

small, equal CW/CCW angles have recognized limitations, including decreased cutting


33

efficiency, more required inward pressure, and a limited capacity to auger debris out

of a canal (Reddy and Hicks, 1998).

Serendipitously, in about 1998, Dr. Ben Johnson and Professor Pierre

Machtou co-discovered the unmistakable advantages of reciprocating NiTi files

utilizing unequal bidirectional movements. Subsequently, in the late 1990s, Machtou

and his endodontic residents extensively analyzed this novel unequal reciprocating

movement using the entire series of not-yet-to market PT files. Dr. Ghassan Yared, a

former student of Professor Machtou, performed exhaustive work to identify the

precise unequal CW/CCW angles that would enable a single reciprocating 25/.08 PT

file to optimally shape virtually any canal (Yared, 2008).

In 2008, a team of 8 international clinicians including Drs. Ben Johnson,

Sergio Kuttler, Pierre Machtou, Wilhelm Pertot, Julian Webber, John West, Ghassan

Yared, and Ruddle, in collaboration with Dentsply International, began the serious

work of developing both a new reciprocating file and motor for shaping canals. In 2011,

following 4 years of research and development, both WaveOne (Dentsply Tulsa Dental

Specialties and Dentsply Maillefer) and RECIPROC (VDW) were internationally

launched as single-file shaping techniques (Ruddle, 2012).

1.7.2. RECIPROC file system

It is a new system for single file reciprocation without prior use of hand files.

It was developed as single-file shaping techniques (VDW GmbH, Munich, Germany).

The system includes three instruments (R25, R40 and R50) (Fig. 1-25). Only one

RECIPROC instrument is used for the canal preparation depending on the initial size

of the canal. The three instruments have regressive taper, which are (Yared, 2012):

1. The R25 has a diameter of 0.25mm at the tip and an 8% (0.08mm / mm) taper over

the first 3mm from the tip. The diameter at D16 is 1.05mm.

2. The R40 has a diameter of 0.40mm at the tip and a 6% (0.06mm / mm) taper over



34

3. The R50 has a diameter of 0.50mm at the tip and a 5% (0.05mm / mm) taper over


Fig. 1-25: RECIPROC instruments (R25, R40 and R50) (Yared, 2012).

VDW. SILVERS® RECIPROC® is battery operated motor (Fig. 1-26) used

with RECIPROC system. The battery is rechargeable and the motor can be used while

the battery is charging. There are preprogrammed settings for reciprocating systems

RECIPROC and WaveOne and for continuous rotary systems Mtwo, FlexMaster, PT,

K3 and Gates. There are 15 further torque/speed continuous rotary settings can be set

and stored for use with other rotary nickel-titanium systems (Yared, 2012).

Fig. 1-26: VDW. SILVER® RECIPROC® (Yared, 2012).

The instruments are used at 10 cycles of reciprocation per second. The motor

is programmed with the angles of reciprocation and speed for the three instruments.

The values of the CW and CCW rotations are different. When the instrument rotates in


35

the cutting direction it will advance in the canal and engage dentine to cut it. When it

rotates in the opposite direction (smaller rotation) the instrument will be immediately

disengaged (Yared, 2012; Yoo and Cho, 2012). The end result, related to the degree

of CW and CCW rotations, is an advancement of the instrument in the canal.

Consequently, only very light apical pressure should be applied on the instrument, as

its advancement would be almost automatic. These angles are specific to the

RECIPROC instruments. They were determined using the torsional properties of the

instruments and are influenced by specific features related to the motor such as torque

(Yared, 2012).

1.7.2.1. Design features of RECIPROC files system

These instruments are made from an M-wire NiTi (Johnson et al., 2008)

that offers greater flexibility and resistance to cyclic fatigue than traditional NiTi (Shen

et al., 2006). The three instruments have non-cutting tips (Fig. 1-27). They have an S-

shaped cross-section (Fig. 1-27), Table (1-4) (Yared, 2012; Vallabhanceni et al.,

2012).

Fig. 1: (A) Non-cutting tip of RECIPROC file (VDW, 2012).

(B) RECIPROC cross-section (Yared, 2012).


36

Table (1-4): Design specifications of RECIPROC NiTi instruments

(Vallabhanceni et al., 2012).

1.7.2.2. Single file / Single use concept

According to the manufacturer’s instructions of RECIPROC file:

1. A RECIPROC instrument is designed for single use in maximum one molar. As

with all nickel titanium instruments, it should be examined during the treatment and

discarded if signs of wear can be seen. If an instrument appears to be bent after

being used in a strongly curved canal, it should be discarded.

2. The RECIPROC system is designed for convenience and safety. The instruments

are delivered ready to use, pre-sterilized in blister packaging and should be simply

discarded after use, making work flow more efficient; eliminating the need to clean

and sterilize instruments, considerably reducing the risk of contamination to office

personnel and eliminating the risk of cross section contamination to patients.

3. The RECIPROC instrument cannot be autoclaved due to its non-autoclavable

handle. This safety feature protects against metal fatigue caused by over use.

1.7.2.3. File selection

Selection of the RECIPROC instrument is based on an adequate pre-

operative radiograph (Fig. 1-28). If the canal is partially or completely invisible on the

radiograph, the canal is considered narrow and the R25 is selected. In the other cases,

where the radiograph shows the canal clearly from the access cavity to the apex, the

canal is considered medium or wide. A # 30 hand instrument is inserted passively (with

a gentle watch winding movement but without filing action) to the WL. If it reaches

the WL, the canal is considered large; the R50 is selected for the canal preparation. If

the # 30 hand file does not passively reach WL, a # 20 hand file is inserted passively


6 S-shaped R25 (25/0.08)

R40 (40/0.06)

R50 (50/0.05)

21, 25, 31mm


37

to the WL. If it reaches WL, the canal is considered medium; the R40 is then selected

for the canal preparation. If the # 20 hand instrument does not reach the WL passively,

the R25 is selected (Yared, 2012).

Fig. 1-28: Selection of the appropriate RECIPROC instrument (Yared, 2012).

1.7.2.4. Shaping technique

The technique is extremely simple. In the majority of canals, only one

RECIPROC instrument is used in reciprocation to complete the canal preparation and

there is no need for hand filing. The access cavity requirements, the straight-line access

to the canals and the irrigation protocol are the same as for standard preparation tech-

niques. It is not necessary to widen the root canal orifice with a GG drill or an orifice

opener (Yared, 2012; Yoo and Cho, 2012).

In reciprocation, clockwise and counterclockwise angles determine the

amplitude of reciprocation, the right and left rotations. These angles are lower than the

angles at which the RECIPROC instrument would usually fracture (if bound). When a

reciprocating file binds in the canal, it will not rotate past its specific angle of fracture.

Therefore, the creation of a glide path to minimize binding is not required for the

RECIPROC instruments. The cutting efficiency of the RECIPROC instruments and the


38

centering ability associated with reciprocation allow the instruments to enlarge

uninstrumented and narrow canals in a safe manner (Yared, 2012).

Before commencing preparation, the length of the root canal is estimated

with the help of an adequately exposed and angulated pre-operative radiograph. The

silicone stopper is set on the RECIPROC instrument at 2/3 of that length. The

RECIPROC instrument is introduced in the canal with a slow in-and-out pecking

motion without pulling the instrument completely out of the canal (Burklein et al.,

2012b; Yared, 2012). The amplitude of the in- and out-movements should not exceed

3-4mm. Only very light pressure should be applied. The instrument will advance easily

in the canal in an apical direction. After three in- and out- movements, or when more

pressure is needed to make the instrument advance further in the canal, or when

resistance is encountered, the instrument is pulled out of the canal to clean the flutes.

(Fig. 1-29) (Yared, 2012; Yared, 2013).

The RECIPROC instrument is used until it has reached 2/3 of the estimated

WL as indicated by the stopper on the instrument. The instrument is then removed from

the canal, the canal is irrigated and a # 10 file is used to determine the length. The

RECIPROC instrument is then reused in the same manner until the WL has been

reached. As soon as the WL has been reached, the RECIPROC instrument is withdrawn

from the canal. The RECIPROC instrument can also be used in a brushing motion

against the lateral walls of wide canals (Yared, 2012; Yared, 2013).

Fig. 1-29: Consequences of root canal preparation with RECIPROC file (left

to right) (VDW, 2012).


39

1.7.3. WaveOne file system

It is a new single-instrument mechanized shaping system (DENTSPLY

Maillefer, Ballaigues, Switzerland). In most instances, the WaveOne concept provides

a single file shaping technique, regardless of the length, diameter, or curvature of any

given canal (Ruddle, 2012; Landwehr, 2013). In fact, it has been shown that a single-

file reciprocating shaping technique utilizing unequal CW/CCW angles is over 4 times

safer and almost 3 times faster than using multiple rotary files to achieve the same final

shape (Grande et al., 2010).

The WaveOne concept represents a solution for any dentist who has concerns

with any of the following (Ruddle, 2012):

Using S.S files for shaping canals.

Breaking mechanically driven files.

Ledging curved canals.

Transporting the prepared foramen.

Using too many shaping files.

Spending too much time preparing canals.

Importantly, the WaveOne single-file technique is the convergence of a

unique file design, advancements in NiTi alloy, and a novel reciprocating movement

(Burklein et al., 2012b; Ruddle, 2012). Strategically, only 1 file is generally utilized

to fully shape virtually any given canal. However, there are 3 WaveOne files available

to effectively address a wide range of endodontic anatomy commonly encountered in

everyday practice (Fig. 1-30) (Kuttler and West, 2012):

Fig. 1-30: The Small, Primary and Large WaveOne files (Ruddle, 2012).


40

1. The WaveOne Small file is used in fine canals. The tip size is ISO 21 with a

continuous taper of 6%.

2. The WaveOne Primary file is used in the majority of canals. The tip size is ISO 25

with an apical taper of 8% that reduces towards the coronal end.

3. The WaveOne Large file is used in large canals. The tip size is ISO 40 with an apical

taper of 8% that reduces towards the coronal end.

1.7.3.1. Design features of WaveOne files system

The WaveOne files have a reverse helix and 2 distinct cross-sections along

the length of their active portions (Fig. 1-31). From D1-D8, the WaveOne files have a

modified convex triangular cross-section, whereas from D9-D16, these files have a

convex triangular cross-section (Ruddle, 2012; Webber et al., 2012).

Fig. 1-31: Two different cross-sections on a single WaveOne file (Ruddle, 2012).

These files are made of a special NiTi alloy called M-wire that is created by

an innovative thermal treatment process (Gutmann and Gao, 2012). The benefits of

this M-wire alloy are increased flexibility and improved resistance to cyclic fatigue of

the instruments (Alapati et al., 2009; Al-Hadlaq et al., 2010).

The WaveOne has two cross-sections that is further enhanced by a changing

pitch and helical angle along their active portions (Fig. 1-32), Table (1-5) (Ruddle,

2012; Webber et al., 2012). The WaveOne files have noncutting modified guiding tips

(Fig. 1-33), which enable these files to safely progress through virtually any secured

canal. Together, these design features enhance safety and efficiency when shaping


41

canals that have a confirmed, smooth, and reproducible glide path (Ruddle, 2012;

Serota, 2012).

Fig. 1-32: The variable pitch flutes along the length of WaveOne instrument

(Webber et al., 2012).

Table (1-5): Design specifications of WaveOne NiTi instruments (Webber et al.,

2012).


3 (D0-D8) modified convex

triangular

(D9-D16) convex triangular

Small (21/0.06)

Primary (25/0.08)

Large (40/0.08)

21, 25,

31mm

Fig. 1-33: Non-cutting modified guiding tip of WaveOne file (Kuttler and West,

2012).

1.7.3.2. Reciprocation movement

The e3 motors (Dentsply Tulsa Dental Specialties) is specially engineered

and programmed to drive the new WaveOne reciprocating files (Fig. 1-34). The

WaveOne motor is rechargeable battery operated with a 6:1 reducing handpiece


42

(Vallabhaneni et al., 2012). This motor produces a feature-specific, unequal

bidirectional file movement. Because of the reverse helix design, the CCW engaging

angle is 5 times the CW disengaging angle. Additionally, it should be noted, this motor

can drive any market version file system in full CW rotation at the desired speed and

torque (Ruddle, 2012; Serota, 2012).

Fig. 1-34: The e3 motor (Ruddle, 2012).

There are 3 critical distinctions with this novel, unequal bidirectional

movement:

1. Compared to continuous rotation, there is a significant improvement in safety, as

the CCW engaging angle has been designed to be smaller than the elastic

metallurgical limit of the file (Ruddle, 2012).

2. Opposed to all other reciprocating systems that utilize equal bidirectional angles,

the WaveOne system utilizes an engaging angle that is 5 times the disengaging

angle. Fortuitously, after three engaging/disengaging cutting cycles, the WaveOne

file will have rotated 360º, or turned one CCW circle. This unique reciprocating

movement enables the file to more readily advance toward the desired WL (Fig. 1-

35) (Ruddle, 2012; Serota, 2012).

3. Compared to an equal bidirectional movement, an unequal bidirectional movement

strategically enhances augering debris out of the canal (De-Deus et al., 2010).

Augering debris in a coronal direction promotes the biological objectives for

preparing canals, 3D disinfection, and filling root canal systems (Ruddle, 2012).


43

Fig. 1-35: Three engaging/disengaging cutting cycles of WaveOne file (Ruddle et

al., 2013).

1.7.3.3. Single file / Single use concept

The WaveOne technique is both a single-file and single-use concept. As

stated, it is a single-file concept given that one single file is able to transition a secured

canal to a well-shaped canal, in most instances. Further, appreciate that a single

WaveOne file is frequently used to prepare multiple canals in a single furcated tooth,

performing a significant amount of work. The WaveOne concept must be considered a

single-use concept due to the obvious stress and wear on the active portion of the file

(Kuttler and West, 2012). This is in line with the growing concern in the dental

community, especially in institutional settings, that all endodontic files be considered

single-use. The rationale behind this legitimate concern is the documentable potential

for cross-contamination between and among patients, regardless of the sterilization

protocol utilized (Letters et al., 2005).

1.7.3.4. File selection

Whilst a good preoperative periapical radiograph will give an indication of

what to expect before the canal is prepared (size and length of the canal, No. of canals,

degree and severity of curvature), only the first hand file into the canal will aid in the

selection of the WaveOne file as follows (Webber et al., 2012):

1. If a # 10 K-file is very resistant to movement, use WaveOne Small file.


44

2. If a # 10 K-file moves to length easily, is loose or very loose, use WaveOne Primary

file.

3. If a # 20 K-file or larger goes to length, use WaveOne Large file.

1.7.3.5. Shaping technique

The WaveOne single-file shaping technique is safe and simplistic. As is

required for any shaping technique, straight line access to each orifice is emphasized.

Attention is directed to flaring, flattening, and finishing the internal axial walls.

Importantly, the orifice(s) should be preenlarged and all internal triangles of dentin

eliminated (Webber et al., 2012).

With an estimated WL and in the presence of a viscous chelator, insert a #

10 file into the orifice and determine if the file will easily move toward the terminus of

the canal. After that, the access cavity is voluminously flushed with a 6% solution of

sodium hypochlorite (NaOCl). Then, shaping can commence, starting with the Primary

25/.08 WaveOne file. Gentle apically directed pressure will typically allow this

instrument to run 2, 3, or 4 mm inward. After every few millimeters of advancement,

or if the Primary 25/.08 WaveOne file will not easily progress, remove this file and

clean and inspect its flutes. Upon removing any mechanical shaping file from any

canal, it is wise to irrigate, recapitulate with a # 10 file, then reirrigate (Burklein et al.,

2012b; Ruddle, 2012).

A brushing motion may be utilized to eliminate interferences, remove

internal triangles of dentin, or to enhance shaping results in canals which exhibit an

irregular cross-section. In one or more passes, continue with the Primary 25/.08 file

through the body of the canal. Removing canyons of restrictive dentin from the coronal

2/3 of a canal creates a more direct path to its apical 1/3, improving accuracy when

determining a precise WL (Ruddle, 2012; Serota, 2012).

When the Primary file will not readily advance in a secured canal, then the

Small 21/.06 WaveOne file may be utilized. This file will typically reach the desired

WL in one or more passes. The Small 21/.06 file may be the only shaping file taken to


45

the full WL. In these instances, the 25/.08 file will generally advance through any

region of a canal where the shape has been previously expanded utilizing the Small

21/.06 bridge file. If the # 30 hand file is loose at length, proceed to the Large 40/.08

WaveOne file to more optimally prepare and finish these larger canals (Ruddle, 2012;

Serota, 2012).

RECIPROC and WaveOne systems are the direct full-sequence counterparts

of the single-file reciprocating systems; these are the new single-file instruments were

well within the range of current rotary full-sequence NiTi systems (Vallabhaneni et

al., 2012). Curved root canals can be instrumented with only minor canal straightening

by only one instrument used in a reciprocating motion (Yared, 2008; Paque et al.,

2011).

A rotary instrument can also fracture if it binds in the canal, especially at its

tip. When using a rotary system the tip of the instrument may bind in the canal; the

motor will keep rotating the instrument while its tip is bound and the instrument will

eventually fracture at a specific angle of rotation. In reciprocation, clockwise and

counterclockwise angles determine the amplitude of reciprocation, the right and left

rotations. These angles, stored in the motor, are significantly lower than the angles at

which the instrument would usually fracture. If the instrument binds in the canal, it will

not fracture because it will never reach the angle at fracture. In this respect, single file

reciprocation is safer than rotary techniques because fracture by binding (fracture by

taper lock or torsional fracture) is eliminated (Yared, 2012).

Working time was four times faster with the single file reciprocation in

comparison with a NiTi rotary preparation technique. RECIPROC was significantly

faster than WaveOne (P < 0.05). The use of RECIPROC decreased the preparation time

by up to 60% (Vallabhaneni et al., 2012). The use of RECIPROC and WaveOne files

resulted in significantly shorter preparation times than Mtwo and PT rotary files

(Burklein et al., 2012a; Burklein et al., 2012b).

Comparing with rotary NiTi systems investigated under a similar

experimental setup, the RECIPROC and WaveOne single-file systems maintained the


46

original canal curvature well (Lim et al., 2013). Both single-file systems showed

relatively good cleaning ability and can be regarded as suitable for cleaning of even

severely curved with only one instrument (Burklein et al., 2012b).

Root canal preparation with both rotary and reciprocating instruments

resulted in dentinal defects. At the apical level of the canals, reciprocating files

produced significantly more incomplete dentinal cracks than full-sequence rotary

systems (Burklein et al., 2013).

1.8. Root canal instrumentation techniques

The preparation of the root canal system is essential for a successful outcome

in root canal treatment (Schilder, 1974). Mechanical debridement of the root canals is

meant to eliminate vital and necrotic tissues from the root canal system, along with

removal of infected dentine. Canal therapy also creates space to facilitate disinfection

by irrigants and medicaments, and an optimal shape for three-dimensional obturation.

An adequate coronal restoration and a microbial-tight root canal filling are necessary

to prevent reinfection. Thus, mechanical preparation and chemical disinfection are

commonly considered together and referred to ‘chemo-mechanical preparation’

(Vaudt et al., 2007).

There are two different principally different approaches: the "apex first" and

the "coronal first" technique. There are several techniques used in root canal

preparation system, the most important ones are (Ingle et al., 2008):

a) Standardized technique.

b) Step-back technique.

c) Step-down technique.

d) Balanced force technique (BF).

e) Anti-curvature filing technique.

f) Crown-down pressure-less technique.

g) Double flare technique.


47

1.8.1. Step-down technique:

A different approach was taken by Goerig et al., in 1982 who advocated

shaping the coronal aspect of a root canal first before apical instrumentation

commenced.

The procedure itself involves the preparation of coronal 2/3 of canal using

Hedstrom files of # 15, 20, and 25. Thereafter, GG drills No. 2 and No. 3, and then

potentially No. 4 are used sequentially shorter, thus flaring the coronal segment of the

main root canal (coronal 1/3 of canal). Then, apical instrumentation is initiated; it

consists of negotiating the remainder of the canal with a small K-file, shaping an apical

2/3 of canal by step-back technique. Copious irrigation and recapitulation will prevent

build up of canal debris. The master apical file (MAF) is usually # 30. After that, the

step back technique is start to complete the apical third preparation, and decreasing the

WL of incrementally larger files. Frequent recapitulation with a # 25 K-file to WL is

advised to prevent blockage of canal (Ingle et al., 2008).

1.8.2. Balanced force technique:

After many years of experimentation, Roane et al., in 1985 introduced the

BF concept of canal preparation. The technique can be described as "positioning and

preloading an instrument through a CW rotation and then shaping the canal with a

CCW rotation".

Balanced Force hand instrumentation begins with the typical triad of

movements: placing, cutting, and removing instruments using only rotary motions.

Insertion is done by a 1/4 (quarter) turn CW rotation while slight or no apical pressure

is applied. Cutting is then accomplished by CCW rotation applying sufficient apical

pressure to the instrument. The amount of apical pressure must be adjusted to match

the file size (i.e., very light for fine instruments to fairly heavy for large instruments).

Pressure should maintain the instrument at or near its clockwise insertion depth (Ingle

et al., 2008).


48

Then counterclockwise rotation and apical pressure act together to enlarge

and shape the canal to the diameter of the instrument. CCW motion should be 120° or

greater. It is important to understand that CW rotation allows the instrument to engage

dentin, and this motion should not exceed 90°. If excess clockwise rotation is used, the

instrument tip can become locked into place and the file may unwind (Ingle et al.,

2008).

Following the cutting rotation, the file is repositioned and the process is

repeated until the corrected WL is reached. The file is then removed from the canal by

a slow CW rotation that loads debris into the flutes and elevates it away from the apical

foramen. Generous irrigation follows each shaping instrument, since residual debris

will cause transportation of the shape (Ingle et al., 2008).

1.9. Apically extruded debris in endodontics

The ultimate object of canal preparation is the elimination of irritant factors

and maintenance of healthy periapical tissues. Some of these irritants, such as necrotic

debris, dentinal particles and irrigating solutions, may extrude from the apical foramen

during canal preparation and induce flare-ups. Therefore, a technique that would

minimize the extrusion of debris would help to reduce the incidence of such flare-ups

(Zarrabi et al., 2006a).

Apical extrusion of infected debris to the periradicular tissues is possibly one

of the principal causes of postoperative pain (Wittgow and Sabiston, 1975). The

causative factors of inter-appointment flare-ups comprise mechanical, chemical and/or

microbial injury to periradicular tissues (Torabinejad et al., 1988). The inter-

appointment flare-up is a true complication characterized by the development of pain,

swelling or both, which commences within a few hours or days after root canal

procedures and is of sufficient severity to require an unscheduled visit for emergency

treatment (Siqueira, 2003).

In asymptomatic chronic periradicular lesions associated with infected teeth,

there is a balance between microbial aggression and host defense in the periradicular


49

tissues. During chemo-mechanical preparation, if the microorganisms are apically

extruded, the host will face a situation in which it will be challenged by a larger No. of

irritants than it before. Consequently, there will be a transient disruption in the balance

between aggression and defense in such a way that the host will mobilize an acute

inflammation to re-establish the equilibrium (Siqueira, 2003).

Moreover, it is well documented in the literature that both uncontaminated

and contaminated dentine and pulp tissue can trigger an inflammatory reaction when

forced periapically during instrumentation (Ruiz-Hubard et al., 1987). The

immunological aspects of postoperative flare-ups were assessed by a No. of researchers

who concluded that antigens originating in the root canal result in the formation of an

antigen-antibody (Ag-Ab) complex when forced beyond the apical foramen, which can

lead to a severe inflammatory response (Naidorf, 1985; Al-Omari and Dummer,

1995; Er et al., 2005). Therefore, it might be assumed that minimizing the amount of

apically extruded material should minimize postoperative reactions (Tasdemir et al.,

2010).

Studies showed that in almost all instrumentation techniques, debris is forced

out apically during root canal preparation. A technique that causes minimal apical

extrusion might reduce periapical inflammation and postoperative flare-ups. Many

factors affect the amount of extruded intracanal materials such as; instrumentation

technique, instrument type, instrument size, instrumentation end point, irrigation

solution, and design of the files (Al-Omari and Dummer, 1995; Beeson et al., 1998;

Reddy and Hicks 1998; Ferraz et al., 2001; Tinaz et al., 2005).

However, the amount of debris extruded apically might vary according to the

technique used; where Martin and Cunningham in 1982 compared the effect of

endosonic and hand manipulation on the amount of root canal material extruded. They

showed that endosonic instrumentation produced less apically extruded material than

did hand filing. Moreover, Fairbourn et al., in 1987 demonstrated that sonic,

ultrasonic and cervical flaring techniques produced less apically extruded debris (AED)

than a conventional filing method. Another study (Reddy and Hicks, 1998) showed


50

that canal preparation in a step-back manner led to increased debris extrusion, in

comparison to canal instrumentation with BF or two rotary techniques (Light Speed

and ProFile 0.04 Taper). It seems that push-pull motions of files during root canal

preparation cause more debris extrusion than techniques that are based on a reaming or

rotational action (Ferraz et al., 2001).

Other studies discussed the effect of different type of instrumentation

technique on AED. The amount of debris forced periapically during root canal

instrumentation using two different techniques (crown-down pressure-less

instrumentation technique, typical step-back technique) was assessed by Ruiz-Hubard

et al., in 1987. They found that a crown-down pressure-less instrumentation technique

had significantly less apical debris extrusion than did a typical step-back technique.

While, Kellow and Al-Hashimi in 2001 compared the amount of debris forced through

the apex by using Flexofile hand instruments in four instrumentation techniques; BF,

step-back filing, step-back reaming and crown down pressure-less techniques. They

found that step-back filing technique produce significantly the largest amount of AED

than others, while BF technique produce significantly the smallest amount of apically

debris compared to others. Canal blockage was also observed and it limited to step-

back techniques.

While McKendry in 1990 compared BF technique with endosonic and step-

back techniques. He concluded that the BF technique extruded less debris apically than

either endosonic or step-back techniques. Also, Al-Omary and Dummer in 1995

showed that among eight hand instrumentation methods, step-back caused the highest

amount of debris compared to BF and crown-down pressure-less technique.

No statistically significant difference was found among NiTi engine driven

instruments (Lightspeed, ProFile 0.04 taper series 29, and NT McXIM) and flex-R files

in BF technique in comparing the amount of AED (Hinrichs and walker, 1998).

Whereas Mangalam et al., in 2002 quantitatively measured the amount of

debris extruded apically in single rooted canals with three different instrumentation

techniques and to quantify the amount of irrigant forced apically. Time taken for each


51

instrumentation was also determined; where group-I was instrumented with K-files by

conventional step back method, group-II with Profile 0.04 series by crown down

technique and group-III using engine driven GG drills and K-files by Hybrid technique.

They found that the extrusion of debris and irrigant in group-I was more than the other

groups. The time taken for group-I was also significantly more.

Engine-driven rotary instruments are suggested to produce less debris than

hand filing techniques since they have a tendency to pull the debris into the flutes of

the instrument, thus leading them out of the root canal in a coronal direction (Martin

and Cunningham, 1982; Siqueira et al., 2002). Moreover, Bidar et al., in 2004

evaluated the amount of AED in conventional and rotary instrumentation techniques.

They mentioned that the differences in the amount of debris produced among rotary

groups (ProFile 0.04 taper series rotary system at three speed: 1000, 2000, and 24000

rpm) was not significant. While, Azar and Ebrahimi in 2005 conducted a comparative

investigation on the amount of AED using the PT, ProFile and hand instrumentation

techniques. They showed that although the mean amount of extrusion with the step-

back technique was higher than the two rotary systems, there were no significant

differences between the three groups.

According to Zarrabi et al., in 2006a, the Race system induces less extruded

debris than the manual technique and the FlexMaster system. Whereas, Kustarci et

al., in 2008 found no significant difference in the amount of debris extruded apically

between manual technique and three rotary systems (K3, Race, FlexMaster).

Whilst Adl et al., in 2009 concluded that both engine driven techniques

(FlexMaster and Mtwo) extruded less apical debris compared to step-back technique

(hand K-file). Also, Mtwo rotary system showed the lowest mean weight of debris

when comparing with FlexMaster rotary system and hand file. While De-Deus et al.,

in 2010 quantitatively evaluated the amount of dentin debris extruded from the apical

foramen by comparing the conventional sequence of the PT Universal NiTi files with

the single-file PT F2 technique. They found that there is no significant difference in

the amount of the debris extruded between the conventional sequence of the PT


52

Universal NiTi files and the single-file PT F2 technique. In contrast, the hand

instrumentation group extruded significantly more debris than both NiTi groups.

Moreover Froughreyhani et al., in 2011 compared the amount of apically

extruded debris using Mtwo instruments with single length technique and RaCe system

using crown-down approach. They found that both instruments tested produced a

considerable debris extrusion. However, the Mtwo system with single length technique

produced significantly more debris extrusion than RaCe system. They suggested that

the non-convex triangular cross section of RaCe system with alternative contact angle

allow the debris to move coronally rather than apically.

Other factor that can affect on AED is the instrument type; where Reddy

and Hicks in 1998 and Ferraz et al., in 2001 investigated the quantity of apical debris

produced in vitro using two hand and different rotary systems. The researchers

concluded that there were no statistical differences between the BF technique and the

engine-driven methods.

While Mehdi et al., in 2009 evaluated the amount of apical debris, using

hand, rotary PT instruments, and rotary ProFile instruments. They found that all

instruments tested caused a measurable apical extrusion of debris. A high significant

difference was observed between the amounts of debris extruded by the PT rotary and

the ProFile, and between the PT hand and ProFile. On the other hand, no significance

difference was found between the PT rotary and the PT hand.

Whilst Tasdemir et al., in 2010 compared the amount of extruded debris

using three rotary NiTi instruments (PT Universal, Mtwo, and BioRaCe). They found

that there were significant differences in the amount of debris extruded among all

groups. The greatest amount of apical debris was extruded by the PT Universal group

and the least by the BioRaCe group. On the other hand, Jindal et al., 2012 found a

non-significant difference between RPT and Mtwo groups.

Whereas Ghivari and Kubasad in 2011 evaluated and compared the amount

of debris and irrigant extruded quantitatively using two rotary (K3, Mtwo) NiTi

instrumentation techniques. They found that K3 system extruded more amount of


53

debris and irrigant compared to Mtwo rotary NiTi system. In Mtwo, because the

distance between the cutting blades increases from the instrument tip to the shaft and

the progressive pitch. Whereas K3 system with asymmetrical cross section and relief

between two radial lands, has a positive rake angle which produces substantial amount

of dentinal debris.

Moreover, Al-Doory and Al-Hashimi in 2012 evaluated the effect of

instrument application frequency on the amount of AED within the same

instrumentation technique, and compared the amounts of AED using three

instrumentation techniques (RPT NiTi file, HPT NiTi file, and Hybrid technique). They

recorded that no significant difference for the effect of instrument application

frequency on the amount of AED.

The instrument size may affect on the amount of AED; where Schilder in

1974 and Weine in 2004 believed that limiting the apical enlargement to # 25 or 30 is

preferable; to minimize the undesirable effect like; ledging or zipping, due to decrease

of the instruments flexibility with increase in its size. While Borges et al., in 2011

studied the influence of apical enlargement on the apical extrusion of debris in canals

with mild and moderate curvatures. They showed that there was no statistically

difference in weights of extruded material between different diameters (P= 0.063).

However, mildly and moderately curved root canals showed significant differences in

the amount of extruded material (P= 0.036) as well as in the interactions between

different curvatures and instruments, 30/.03 and 45/.02 diameters (P= 0.017).

Instrumentation end point is another factor that can affect on amount of AED

by apical foramen; where Martin and Cunningham in 1982 showed that

instrumentation short of the apical foramen decreased the amount of debris extrusion,

with both endosonic instruments and K-files. Myers and Montgomery in 1991 found

that step-back canal preparation short of the apical foramen produced an apical plug

that blocked debris extrusion. Another study showed preparing the canal 1mm short of

WL caused the least debris beyond apical foramen despite the technique used (Beeson

et al., 1998).


54

While Lambrianidis et al., in 2001 reported that greater extrusion was

detected with an intact apical constriction, as opposed to enlargement of the apical

constriction, where an apical plug formation may be present. The incorporation of

apical patency in the enlargement procedure did affect the amount of extruded debris

where apical patency caused in more debris extrusion. This may be due to formation

of apical dentin plug when apical patency was not used, thus decreasing the amount of

extruded material (Hamouda et al., 2011).

Whereas Hamouda et al., in 2011 evaluated the effect of apical patency on

AED during canal enlargement using hand (RT S.S file), or rotary instruments (PT and

HeroShaper NiTi files) and they found that incorporation of apical patency in the

enlargement procedure did affect the amount of extruded debris where apical patency

caused in more debris extrusion, and PT rotary NiTi files extruded higher amount of

debris followed by HeroShaper file, and the lowest amount of debris with RT file.

The presence of irrigation solution and types of it can affect on amount of

AED by apical foramen; where Vande Visse and Brilliant in 1975 first quantified the

amount of debris extruded apically during instrumentation. They found that

instrumentation with irrigant produced extrusion, whereas instrumentation without

irrigant produced no collectible debris; it can be assumed that root canal preparation

without using an irrigant might result in some debris accumulation at the apical end of

the root canal, and this might form an apical plug. This might be a reason for not having

significant AED after instrumentation. Ghivari et al., in 2011 studied the influence of

instrumentation technique on the amount of irrigant extruded apically. They found that

step-back hand instrumentation technique extruded larger amount of irrigant than the

rotary instrumentation technique.

While Parirokh et al., in 2012 compared the amount of debris extruded

apically from root canals when 3 different irrigants; 2.5% NaOCl, 5.25% NaOCl, 2%

chlorhexidine (CHX) were used during canal preparation with rotary instruments; and

they found that the type of irrigant used can affect the amount of AED. The 5.25%

solution of NaOCl had the greatest amount of debris.


55

Sodium hypochlorite was the most popular irrigant and has proved to be one

of the best irrigation solution; however, it affects the accuracy of measurement of the

AED (Mayers and Montogomery, 1991; Bidar et al., 2004; Logani and Shah,

2008). Mckendry in 1990 and Haung et al., in 2007 used NaOCl as irrigating solution;

and they found that dryness of the irrigant resulted in salt crystals, which can't be

separated from the cutting debris.

The design of the files may be affect on debris extrusion; where Elmsallati

et al., in 2009 quantitatively compared the amount of debris extruded apically from

curved canals when using rotary NiTi files with different pitches and sequences of use

under the same preparation technique. They found that there was no significant

difference observed between two sequences. There were significant differences in

sequence 1 between the short pitch group and the others. Also, there were significant

differences between the long pitch and others in sequence 2, except between the short

and medium pitches.

Many of studies used one type of teeth. The mandibular premolars were used

by Zarrabi et al., in 2006a; Kustarci et al., in 2008; Mehdi et al., in 2009; Ghivari

and Kubasad in 2011; Jindal et al., in 2012. While Huang et al., in 2007; Mitchell

et al., in 2011 and Burklein et al., in 2012a used maxillary anterior teeth. De-Deus et

al., in 2010 and Howard et al., in 2011 used mesial roots of mandibular molars;

Hamouda et al., in 2011 used distal roots of mandibular molars; Al-Doory and Al-

Hashimi in 2012 used palatal roots of maxillary molars.

Other researchers used more than one type of teeth. Myers and

Montgomery in 1991 used maxillary lateral incisors and mandibular premolars;

Ferraz et al., in 2001 used maxillary and mandibular central and lateral incisors;

Kellow and Al-Hashimi in 2001 used mesial roots of mandibular and maxillary

molars; Saad et al., in 2007 used anterior teeth and premolars; Elmsallati et al., in

2009 used mesiobuccal root of the maxillary 1st molars and mesiobuccal root canals of

the mandibular 1st molars.

Chapter Two

Materials and

Methods

Materials and Methods Chapter Two

56

2.1. Materials and Equipment

2.1.1. Materials

1. Seventy-five mandibular premolars teeth.

2. Hand ProTaper NiTi endodontic files (Dentsply-Maillefer, Ballaigues,

Switzerland). Lot No. (1113560) (Fig. 2-1).

3. Rotary ProTaper NiTi endodontic files (Dentsply-Maillefer, Ballaigues,

Switzerland). Lot No. (0524560) (Fig. 2-2).

4. Rotary Mtwo NiTi endodontic files (VDW GmbH, Munich, Germany). Lot No.

(010141) (Fig. 2-3).

5. Reciprocating RECIPROC NiTi endodontic R40 files (VDW GmbH, Munich,

Germany). Lot No. (012152) (Fig. 2-4).

6. Reciprocating WaveOne NiTi endodontic Large files (Dentsply-Maillefer,

Ballaigues, Switzerland). Lot No. (1057920) (Fig. 2-5).

7. Stainless steel Barbed Broaches (Dentsply-Maillefer, Switzerland). Lot No.

(Y08.001).

8. Stainless steel K-files size (15-40) kits (Mani-INC, Japan). Lot No. (R101326700).

9. Glass flask (length: 53mm; width: 26mm; capacity: 18ml) (Fig. 2-6).

10. Collecting glass vials (length: 50mm; width: 21mm; capacity: 12ml) (Fig. 2-7).

11. Diamond disc bur (diameter: 0.2mm x 22mm) (Komet, Germany).

12. Distilled water (Parenteral Drugs, India). Expire date (11/2014).

13. Normal saline (Sodium Chloride 0.9%) (Adwic, Egypt).

14. NaOCl solution 5% (Bareket, Chlorine Bleacher, Turkey). Expire date (10/2017).

15. Gauge 25 needles (Medical Jects Company, Syria). Expire date (5/2014).

16. Monoject irrigating syringe with 27-gauge safe-tipped notched needle (United

States). Expire date (2/2016).

17. Dental floss (Freshmint, China).

18. Rubber dam material sheets (Svenska Dental Instrument AB, Sweden).

19. Calcium chloride (CaCl2) crystals (Shandong, China).


57

Fig. 2-1: Hand ProTaper file kit. Fig. 2-2: Rotary ProTaper file kit.

Fig. 2-3: Mtwo file kit.

Fig. 2-4: RECIPROC file kit. Fig. 2-5: WaveOne file kit.


58

2.1.2. Instruments

1. Endodontic ruler (Dentsply-Maillefer, Switzerland).

2. Transfer sponge (Dentsply-Maillefer, Switzerland).

3. Tweezer (Derfla, Germany).

4. Tissue forcep (Eschmann, England).

5. Periodontal curette (Hu-Friedy, USA).

6. Dental forcep (Timesco, England).

7. Rubber stopper puncher (China).

8. Rubber dam puncher (Epoch, Japan).

9. Magnifying eye lens (Dimaron, Germany) (x 15).

2.1.3. Equipment

1. Electric motor Endo-Mate DT (NSK-Nhkanishi Inc®, Japan) (Fig. 2-8).

2. SILVER® RECEPROC® motor (VDW GmbH, Munich, Germany) (Fig. 2-9).

3. WaveOneTM motor (Dentsply-Maillefer, Ballaigues, Switzerland) (Fig. 2-10).

4. Sensitive electronic balance (0.00001g) (Kern-ABT 100-5M, Germany).

5. Engine electric motor (MF-Perfecta/ W&H, Austria)

6. Straight handpiece (NSK, Japan).

7. Desiccator (Shanghai, China).

8. Digital caliper (Whitworth, United States).

9. Rectangular base wood.

10. Hot air oven (Jrad, Syria).

11. Halogen light curing unit (Dentsply, Switzerland).

12. Contra-angle handpiece (NSK Endo-Mate DT, Japan).


59

Fig. 2-6: Glass flask. Fig. 2-7: Collecting glass vial.

Fig. 2-8: Endo-Mate DT motor.

Fig. 2-9: SILVER® RECEPROC® motor. Fig. 2-10: WaveOneTM motor.


60

Fig. 2-11: Some of materials, instruments, and equipment used in the study.

2.2. Methods

2.2.1. Sample selection

Seventy-five freshly extracted sound mandibular premolar teeth (extraction

was done for orthodontically reasons, and patient's age ranged from 20-30 years old)

with straight root were selected for this study. Teeth, which had immature apices,

calcified canals, root fracture, or crack were excluded from the study. The criteria for

roots selection included the following (Mehdi et al., 2009; Kustarci et al., 2012):

1. Straight root.

2. Mature centrally located apical foramen. For all roots, # 20 K-file was inserted

passively to full WL, and couldn’t pass beyond the WL through the apical foramen

(Tasdemir et al., 2010; Burklein et al., 2012a).

3. Patent apical foramen. For all roots, # 10 K-file could pass through the apex without

any resistance; while # 15 K-file could pass through the apex with resistance (Al-

Doory and Al-Hashimi, 2012).

4. Root devoid of any resorption, crack or fracture.

5. The root would be 14mm in length.


61

2.2.2. Sample preparation

After extraction, all selected teeth were cleaned from soft periodontal tissue

by periodontal curette, and immersed in 2.5% NaOCl for one hour. Then, the root

surfaces were verified with a magnifying eye lens and light cure device for any visible

cracks or fractures. Teeth were then stored in normal saline with daily change till the

time of use (Hamouda et al., 2011).

To facilitate instrumentation, and eliminate any variables in access

preparation, all teeth were decoronated by using a diamond disc under copious water

to establish a uniform length of 14mm (Zarrabi et al., 2006a). Then, all roots were

measured using digital caliper (Fig. 2-12).

Fig. 2-12: (A) Determining the length of the root.

(B) Sectioning of the root.

(C) Length of the root with digital caliper.


62

The pulpal tissue was removed by using barbed broach. The exact location

of apical foramen and the patency of the canals were verified by insertion of # 15 K-

file into the canal and advancing until it was visualized at the apical foramen. The WL

was obtained by subtracting 1mm from the length of the root (Tasdemir et al., 2010).

2.2.3. Sample grouping

The specimens were randomly divided into five groups (each group

containing 15 samples) according to the type of instrumentation systems used (Fig. 2-

13):

Fig. 2-13: Sample organization into five groups.

2.2.3. Method of sample fixation and debris collection

All collecting vials were coded numerically and weighed with electronic

balance. This is called the pre-instrumentation weight. The vials were stored in the

desiccator that contained CaCl2 until used (Kellow and Al-Hashimi, 2001).

The method used for debris collection was carried out as described by Myers

and Montgomery in 1991:

Group I

•15 samples were instrumented by hand ProTaper system (Handtechnique).

Group II

•15 samples were instrumented by rotary ProTaper system (fullrotary NiTi technique).

Group III

•15 samples were instrumented by rotary Mtwo system (fullrotary NiTi technique).

Group IV

•15 samples were instrumented by single file RECIPROC system(reciprocating technique).

Group V

•15 samples were instrumented by single file WaveOne system(reciprocating technique).


63

1. A flask was inserted in the hole of a specially designed rectangular wood base that

give fixation to the flask during instrumentation (Fig. 2-14).

Fig. 2-14: Insertion of the flask inside a hole in a rectangular wood base.

2. Each vial was inserted inside the flask to avoid any contamination during

instrumentation (Fig. 2-15).

Fig. 2-15: Insertion of the vial inside flask.

3. The rubber stopper of each vial was punctured with rubber stopper puncher.

4. Each root was inserted inside rubber stopper (in the center) (Fig. 2-16).

Fig. 2-16: Root fixation in the center of rubber stopper.


64

5. The root/ stopper assembly was fitted in the pre-weighed glass vial (where the apex

of the root was inserted inside the vial) (Figs. 2-17, 18).

Fig. 2-17: Root and stopper were fitted in the glass vial.

Fig. 2-18: Glass flask held vial and root (drawing illustration).

A, root. B, glass vial. C, glass flask.

6. The flask was coated from the external surface with rubber dam material and

ligature with floss.

7. A vented needle (25-gauge) was inserted through the rubber stopper to equalize the

pressure inside and outside of vials, where only the vented needle and root appeared

from the top area for working (Fig. 2-19).


65

Fig. 2-19: Coating the flask with rubber dam material, and insertion of the

needle through the rubber stopper.

2.2.5. Preparation of canals

The sequences used in this study were done according to the manufacturer’s

instructions for each system. All canals prepared to MAF # 40.

Disposable plastic syringe 3ml with 27-gauge needle was used for irrigation

in this study. The needle tip was inserted passively and never allowed to bind as the

irrigant was being slowly deposited into the canal and never allowed to reach more

than 2mm from the WL (needle tip wasn’t passed more than 11mm inside canal)

(Kellow and Al-Hashimi, 2001; Al-Doory and Al-Hashimi, 2012; Parirokh et al.,

2012).

After each file size of the (hand and rotary files) or after three pecking motion

of the (reciprocating files), the file was removed from the canal to clean the flutes from

debris to prevent clogging of files during instrumentation and the canal was irrigated

with 1mm of DW. The canal remain patent by insertion # 15 K-file (Hamouda et al.,

2011). When the instrumentation was completed, 1ml of DW was used as final flushing

to clean the remnant debris inside the canal (Zarrabi et al., 2006a; Froughreyhani et

al., 2011; Burklein et al., 2012a).

Collecting vials were carried with tissue forcep at all time (tissue forcep was

used as vial carrier). All instrumentations were done by single operator (Myers and

Montgomery, 1991; Mehdi et al., 2009).


66

1. Group I:

Hand ProTaper instruments were used according to the manufacturer’s

instructions using rotational movement in hour sense exerting sufficient pressure at

apical level. HPT file was engaged dentin lightly by rotating the handle CW until the

file just snug, then disengaged the file by rotating the handle CCW, after that the dentin

was cutted by rotating the handle CW while simultaneously withdrawal of the file.

Handle motion was repeated until desired length was achieved. The canals were

instrumented to MAF # F4/.06. The instrumentation sequence was started as following

(Fig. 2-20):

S1 (shaping file # 1) and Sx (auxiliary file) were used sequentially to 3/4 of WL

(9mm).

S1 was used to full WL.

S2 (shaping file # 2) was used to full WL.

Finishing files (F1, F2, F3, and F4) were used sequentially to full WL. The last file

(F4) was regarded as MAF.

Fig. 2-20: (A) Instrumentation of the canal by hand ProTaper files.

(B) Hand ProTaper set.

2. Group II:

Rotary ProTaper instruments were used according to the manufacturer’s

instructions using (Endo-Mate motor) at constant speed 300 rpm (1.4Ncm). The

instrumentation was completed in crown down manner using gentle in and out motion.

The canals were instrumented to MAF # F4/.06.


67

The instrumentation sequence of rotary PT NiTi files was used as the same

as the sequence of HPT NiTi files (Fig. 2-21).

Fig. 2-21: (A) Instrumentation of the canal by rotary ProTaper files.

(B) Rotary ProTaper set.

3. Group III:

Rotary Mtwo instruments were used according to the manufacturer’s

instructions using (Endo-Mate motor) at constant speed 280 rpm (1.4Ncm). The

instrumentation was completed in full-length technique using gentle in and out motion.

The canals were instrumented to MAF # 40/.06 (Fig. 2-22). When full WL was reached,

the next instrument in the sequence was used. The instrumentation sequence was

started as following:

# 10 file was used to full WL.








68

Fig. 2-22: (A) Instrumentation of the canal by Mtwo files.

(B) Rotary Mtwo set.

4. Group IV:

A R40/.06 RECIPROC file was used in a reciprocating motion according to

the manufacturer’s instructions using (SILVER® RECIPROC® endo motor). The

silicon stopper was set on the RECIPROC file at 2/3 of WL (9mm). Then, the file was

introduced in the canal with a slow in-and-out pecking motion without pulling the

instrument completely out of canal. After three in-and-out movements, the RECIPROC

file was pulled out of the canal to clean the flutes, and the canal was irrigated with 1ml

of DW. The RECIPROC file was used until it had reached 2/3 of the WL (9mm) as

indicated by stopper on the file. Then the file was reused in the same manner until the

WL had been reached (Fig. 2-23).

Fig. 2-23: (A) Instrumentation of the canal by RECEPROC R40 file.

(B) R40 file.


69

5. Group V:

A large WaveOne file (# 40/.08) was used in a reciprocating motion

according to the manufacturer’s instructions using (WaveOneTM endo motor). The

silicon stopper was set on the WaveOne file at 2/3 of WL (9mm). Then, the file was

introduced in the canal with a slow in-and-out pecking motion without pulling the

instrument completely out of canal. After three in-and-out movements, the WaveOne

file was pulled out of the canal to clean the flutes, and the canal was irrigated with 1ml

of DW. The WaveOne file was used until it had reached 2/3 of the WL (9mm) as

indicated by stopper on the file. Then the file was reused in the same manner until the

WL had been reached (Fig. 2-24).

Fig. 2-24: (A) Instrumentation of the canal by large WaveOne file.

(B) Large WaveOne file (size 40).

Each HPT, RPT, and Mtwo instruments were used five times before being

replaced (Azar and Mokhtare, 2011; Carvalho-Sousa et al., 2011). While the

reciprocating RECIPROC and WaveOne instruments were used one time only

(Vallabhaneni et al., 2012).

2.2.6. Collection of debris and storage of vials

On completion of the root canal preparation, the ligature of dental floss was

cutted and removed. Then, the root was separated from collecting vial where the root

apex was washed with 1ml of DW in the collection vial (De-Deus et al., 2010;

Froughreyhani et al., 2011) (Fig. 2-25).


70

Fig. 2-25: Washing the apex of the root with distilled water.

Then the vials were placed in dry-heat oven at 110oc and were checked every

half hour until the vials appeared dry (Kellow and Al-Hashimi, 2001) (Fig. 2-26),

after that the vials were removed from the oven and placed in a dry sealed desiccator

which contains CaCl2 crystals for at least 24 hours before beginning weighing the vials

to absorb the moisture (Kellow and Al-Hashimi, 2001; Zarrabi et al., 2006a;

Zarrabi et al., 2006b) (Figs. 2-27, 28). The vials were removed from desiccator and

weighed daily with an electronic balance with an accuracy of (0.00001g) (Fig. 2-29),

until three consecutive weights with a difference of < 0.00002g were obtained for each

vial, and the mean value was calculated, this is called the mean post-instrumentation

weight (Burklein et al., 2012a; Parirokh et al., 2012).

Fig. 2-26: Samples inside oven.


71

Fig. 2-27: Dry debris collected in Fig. 2-28: Placement of vials

a glass vial. in the desiccator.

Fig. 2-29: Sensitive electronic balance.


72

The pre-instrumentation weight was subtracted from the post-

instrumentation weight of each vial and the difference was recorded as the weight of

the extruded debris (Myers and Montgomery, 1991; Burklein et al., 2012a; Kustarci

et al., 2012).

2.3. Statistical analysis

The following statistical methods were used to analyze the collected data:

A) Descriptive statistics: including mean, standard deviation (SD), minimum (Min.),

maximum (Max.), and graphical presentation by bar chart.

B) Inferential statistics: including:

1. One-way analysis of variance test (ANOVA) to find any statistically significant

difference among the groups.

2. Least significant difference test (LSD) to find any significant difference between

every two groups.

In the above tests, P-values equal to or more than 0.05 (P ≥ 0.05) were

considered as statistically non-significant (NS), and P-values less than 0.05 (P < 0.05)

were considered as statistically significant (*), whereas P-values equal to or less than

0.01 (P ≤ 0.01) were considered as statistically highly significant (**), and P-values

less than 0.001 (P ≤ 0.001) were considered as statistically very highly significant

(***).

Chapter three

Results

Results Chapter Three

73

Results

Data that represent the amount of AED values for all groups were displayed

in the appendices (I, II, III, IV and V).

According to the results of this study, all groups induced extrusion of debris

with different values, Tables (3-1).

Tables (3-1): The amount of apically extruded debris for all samples (in mg).

Sample No. Group I Group II Group III Group IV Group V

1 0.97 0.99 0.89 0.84 0.67

2 0.65 0.67 0.62 1.37 0.86

3 0.63 0.67 0.48 1.38 0.96

4 0.58 0.75 0.89 0.85 0.75

5 0.77 0.57 0.46 1.14 0.85

6 0.64 0.64 0.41 1.30 0.63

7 0.66 0.63 0.63 0.84 1.16

8 0.69 0.65 0.62 0.92 1.10

9 0.68 0.97 0.51 0.79 1.06

10 0.94 0.89 0.69 0.82 0.66

11 1.08 0.69 0.71 0.95 0.72

12 0.59 0.59 0.53 0.93 0.70

13 0.67 0.66 0.52 0.92 1.16

14 0.66 0.57 0.54 0.79 1.15

15 0.85 1.00 0.50 1.15 0.61


74

The results of the descriptive statistics which include Min., Max., mean

values (in mg), and SD of AED for all groups are shown in Table (3-2) and (Fig. 3-1).

Table (3-2): The mean values of apically extruded debris (in mg) and SD for all

groups.

Groups N Mean SD Min. Max.

I 15 0.737 0.152 0.580 1.080

II 15 0.729 0.154 0.570 1.000

III 15 0.600 0.145 0.410 0.890

IV 15 0.999 0.212 0.790 1.380

V 15 0.869 0.210 0.610 1.160

From Table (3-2) and (Fig. 3-1), Mtwo group (III) showed the lowest mean

value of AED in comparison with other groups followed by RPT (II), HPT (I), and

WaveOne (V) groups respectively. While the RECIPROC group (IV) has a highest

mean value.

Analysis of variance (ANOVA) test was performed to identify the presence

of any statistically significant difference among groups, Table (3-3).


75

Fig. 3-1: Bar chart graph for mean of apically extruded debris among five groups.

Table (3-3): ANOVA test for mean of apically extruded debris among groups.

Sum of Squares

(SS)

df Mean

Square (MS)

F-

test

P-value Sig.

Between Groups 1.389 4 0.347

11.067

0.000

*** Within Groups 2.197 70 0.031

Total 3.586 74

P ≤ 0.001 Very High Significant (VHS) * * *

From Table (3-3), ANOVA test showed a very highly significant difference

among groups.


76

The least significance difference test (LSD) was performed for multiple

comparisons between groups, Table (3-4).

Table (3-4): LSD test for multiple comparison between groups.

P ≥ 0.05 Non-Significant (NS) P < 0.05 Significant (S) *

P ≤ 0.01 High Significant (HS) * * P ≤ 0.001 Very High Significant (VHS) * * *

Groups

Mean Difference

(I-J)

SE P-value Sig.

Group I Group II 0.00800 0.06469 0.902 NS

Group III 0.13733 0.06469 0.037 *

Group IV - 0.26200 0.06469 0.000 ***

Group V -0.13200 0.06469 0.045 *

Group II Group III 0.12933 0.06469 0.049 *

Group IV -0.27000 0.06469 0.000 ***

Group V -0.14000 0.06469 0.034 *

Group III Group IV -0.39933 0.06469 0.000 ***

Group V -0.26933 0.06469 0.000 ***

Group IV Group V 0.13000 0.06469 0.048 *


77

The results of the LSD test showed that there were no significant differences

between group I (HPT) and group II (RPT) (P ≥ 0.05). Group I (HPT) showed a

significant difference (P < 0.05) with group III (Mtwo) and group V (WaveOne), and

showed a very highly significant difference (P ≤ 0.001) with group IV (RECIPROC).

Group II (RPT) showed a significant difference (P < 0.05) with group III

(Mtwo) and group V (WaveOne), and showed a very highly significant difference (P

≤ 0.001) with group IV (RECIPROC).

Group III (Mtwo) showed a very highly significant difference (P ≤ 0.001)

with group IV (RECIPROC) and group V (WaveOne).

Group IV (RECIPROC) showed a significant difference (P ≥ 0.05) with

group V (WaveOne).

Chapter Four

Discussion

Discussion Chapter Four

78

Discussion

Root canal instrumentation requires technical knowledge to be applied to the

biological area, so as to obtain a well instrumented and disinfected canal without

damage to its biological structure. Since the root canal includes the space that contains

the pulpal organ, one of its ends is in the pulp chamber and the other(s) corresponds to

the apical foramina. Thus, instrumentation of root canals can cause extrusion of

material through the foramen by virtue of the anatomy of the canal itself (Vansan et

al., 1997).

During root canal treatment, debris and irrigant may extrude from the apical

foramen and cause post-instrumentation pain or flare-up. These debris mostly contain

pulp tissue remnants, dentin chips, microorganisms, necrotic tissue, and root canal

irrigants (Siqueira, 2003). When debris is pushed out of apical foramina, it will result

in an Ag-Ab reaction. This reaction will generate an acute inflammatory reaction in the

periapical tissues, and cause damage to the cell membrane resulting in prostaglandins

release, bone resorption, amplification of the kinin system and ultimately pain for

patient (Ruiz-Hubard, 1987; Al-Omari and Dummer, 1995).

The main objective of this study was to compare the amount of AED in

different root canal instrumentation systems (HPT, RPT, Mtwo, RECIPROC, and

WaveOne).

Freshly extracted, single human straight roots, of mandibular premolars were

used, because using one type of teeth can increase the similarity and standardization

among specimens (Kustarci et al., 2012).

Since the maturity and patency of the root canal will greatly affect the

amount of debris extruded. In this study, # 15 file is the largest file size that could

passed through the apical foramen and considered as the size of the physiological apex.

The crowns of teeth were removed to establish a uniform length of root and

a fixed and reliable reference point. Also, any soft tissue was removed by barbed

broach prior to instrumentation, making sure that the debris extruded was dentinal


79

shaving and not soft tissue remnants (Reddy and Hicks, 1998; Logani and Shah,

2008; Jindal et al., 2012). All roots were instrumented to the same size of MAF (40)

to minimize group disparity (Mangalam et al., 2002; Mehdi et al., 2009; Jindal et

al., 2012).

Dryness of the NaOCl irrigant resulted in salt crystals which cannot be

separated from the cutting debris, so that NaOCl was replaced by DW to avoid such

discrepancy in data collection (Hamouda et al., 2011; Jindal et al., 2012).

Irrigation was conducted in a similar manner, in all five groups. DW was

used after each instrument file or 3 pecks (Burklein et al., 2012a); 1ml of DW was

delivered (Froughreyhani et al., 2011; Jindal et al., 2012). Also, a monoject

irrigating syringe with gauge 27, safe-tipped notched needle was used. The needle tip

inserted passively without resistance and never allowed to bind the walls of the canal

(Al-Doory and Al-Hashimi, 2012; Burklein et al., 2012a).

Instrumentation was confined to 1mm short of the apical foramen

(Hamouda et al., 2011; Burklein et al., 2012a) because WL 1mm short of canal

length contributed to significantly less debris extrusion, also when the instrumentation

is performed to the apical foramen; more debris is forced apically than when

instrumentation is 1mm short of the apical foramen (Myers and Montgomery 1991;

Beeson et al., 1998; Jindal et al., 2012).

In order to minimize the variables through the study, all the canals were

instrumented by one operator (the researcher) (Burklein et al., 2012a). Also, the

researcher was trained to practice all instrumentation techniques before starting the

actual experimental work; which was performed according to manufacturer's

instructions. The operator was shielded from seeing the root apex during the

instrumentation procedure by a rubber dam that obscured the glass flask (Myers and

Montgomery 1991; Mehdi et al., 2009; Tasdemir et al., 2010). During continuation

of the actual experimental work, a sufficient time intervals between each sample was

maintained, to avoid hand fatigue of the operator, which may have an effect on the final

results of the present study.


80

Avoiding contamination of the collecting vials is very crucible through the

study. Using larger outer glass flask and rubber dam sheet will prevent contamination

of collection vial during instrumentation and irrigation procedure. Also, the use of

tweezer and tissue forcep to transfer vials from and to desiccators prevent the

contamination of the vials.

The vials were placed in the hot air oven at 110°C and were checked every

half hour until the vials appeared dry then placed the vials in dry sealed desiccator

contained on CaCl2 to ensure that all moisture was eliminated from debris and prevent

moisture absorption from the surrounding environment that may increase weight of

vials in order to obtain the net weight of the vial. Fluctuation of temperature and

humidity during weighing of the samples greatly affect the results. In order to avoid

this effect, the weighing was done when the temperature between (24°C - 28°C) and

humidity between (48% - 55%).

All works was done in single closed room where all materials, instruments

and equipment were supplied in this room to achieve a standardization in study and

minimize the external effect of environment on the study.

4.1. Apically extruded debris of Mtwo and other groups

The results of this study showed that all instrumentation systems produced

AED with different values, that was in agreement with (Tinaz et al., 2005; Mehdi et

al., 2009; Tasdemir et al., 2010; Burklein et al., 2012a; Al-Doory and Al-Hashimi,

2012), who found that all the instrumentation techniques extruded debris apically.

According to the results of this study, Mtwo system was significantly

extruded the lowest mean of AED in comparing to other groups, and this result is in

agreement with (Burklein et al., 2012a) who showed that Mtwo file produced the

lowest mean of AED.

According to the design features of Mtwo, the space for dentin removal is

deeper at the back of the blade, and this may reduce the risk of apical extrusion

(Ghivari and Kubasad, 2011). Moreover, the No. and depth of the flutes in the Mtwo


81

instruments differ from tip to handle with shallower flutes near the tip (the instruments

have a progressively widening space between blades from the tip toward the handle),

which may increase the capacity to remove debris coronally (Malagnino et al., 2006;

Schafer et al., 2006a; Schafer et al., 2006b).

When comparing the cross section of Mtwo with PT system, Mtwo

instruments possess double-cutting edge and S-shaped geometry with minimum radial

contacts and have a smaller cross-sectional area, which increases their flexibility and

providing maximum space for dentin removal, as well as Mtwo has large and deep

flutes for continuous upwards evacuation of dentine chips (Inan and Gonulol, 2009;

Ghivari and Kubasad, 2011), while PT instruments possess three sharp cutting edges

and convex triangular cross section. So that, the debris space of PT was smaller than

that of Mtwo and this may be lead to more AED from PT file than Mtwo file (Tasdemir

et al., 2008).

The shorter pitch design extruded less debris apically than longer ones,

because the short pitch files have more threads along the same length than long pitch

files. They have more grooves between the cutting edges, to entrap more debris during

preparation, which in turn might reduce the quantity of debris extruded apically

(Elmsallati et al., 2009). Also, Diemer and Calas in 2004 reported that the long pitch

design gives the instrument more ability to cut. However, it may leave larger apical

canals than the short pitch design. The long pitch design could be more efficient than

the short pitch one for cleaning and shaping of canals, even though it extruded more

debris apically. The long pitch design of the PT instruments may cause a greater

amount of debris to be extruded apically (Elmsallati et al., 2009). While in Mtwo, the

increasing pitch from tip to shaft allowed a more delicate cutting action at the apex and

a more aggressive one in the coronal portion, also transportation of debris toward the

apex is reduced (Vaudt et al., 2007; Jabbar and Al-Hashimi, 2010).

Mtwo system has gradual increasing of tapering while PT system has

aggressive increasing of tapering, that result to a faster cutting and more debris in PT

system (Logani and Shaha, 2008). This agrees with the findings of (Tasdemir et al.,


82

2010, Burklein et al., 2012a; Jindal et al., 2012) whose results showed that PT

extruded more debris than Mtwo.

As manufacturer's information of Mtwo, design of it enables each instrument

to prepare a glide path for the following instrument. Each Mtwo instrument is used up

to the full WL without apical pressure; and this leads to decrease the cutting of dentinal

debris by next Mtwo instrument and then decrease the amount of debris extruded

apically by each next Mtwo instrument in comparison with instruments that don’t

prepare a glide path for following instrument. Full length technique (simultaneous

technique) of Mtwo, compared to the coronal enlargement created by crown-down

technique, only removes as much substances as needed without early coronal

enlargement for progression toward apex; this prevents unnecessary weakening of the

tooth. This leads to decrease the cutting action of Mtwo in comparison with other

instruments that used in crown down technique, and thus leads to decrease the amount

of AED of full length technique.

4.2. Apically extruded debris of hand and rotary ProTaper

The results of this study showed that HPT extruded non-significantly more

debris than RPT and significantly more debris than Mtwo. This result agrees with the

result of (Ghivari et al., 2011), but disagrees with (Logani and Shaha, 2008; Mehdi

et al., 2009) whose results showed that RPT extruded more debris than HPT. The time

of contact between the file and the root canal wall and rotational speed and torque may

a factor that affect the amount of AED. The engine-driven rotary file (RPT and Mtwo)

contacted the apical area for a lesser period of time and the rotational speed and torque

is fixed, whereas, the HPT file prepared the apical area for an extended period of time

and the rotational movement of the file was an "operator controlled variable factor"

(Kustarci et al., 2008; Logani and Shaha, 2008).


83

4.3. Apically extruded debris of full rotary and reciprocating systems

According to the results of this study, both reciprocating single-file systems

(RECIPROC and WaveOne) extruded significantly more debris in comparing to all

other groups. These results are in agreement with (Burklein et al., 2012a). Adl et al.,

in 2009 and Jindal et al., in 2012 suggested that reduction of debris extrusion in rotary

preparation techniques is not due to the crown down technique but rather related to

rotational motion of files. A probable explanation for this finding is that rotary motion

tends to pull dentinal debris into the flutes of the file and directs it toward the coronal

aspect of the canal (Beeson et al., 1998; Reddy and Hicks, 1998; Tanalp et al., 2006;

Kustarci et al., 2008).

Ruddle in 2012, concluded from another study of Blum et al., in 2003 that

continuous rotation compared to reciprocation, requires less inward pressure and

improves capacity to auger the debris out of a canal.

Since reciprocating movement is formed by a wider cutting angle and a

smaller releasing angle, while rotating in the releasing angle, the flutes in reciprocating

files will not remove debris but push them apically. Moreover, both WaveOne and

RECIPROC techniques use a single file of greater taper (.06, .08) respectively, which

directly reach the apex. In order to reach the apical WL, reciprocating instruments are

used with force directed apically, which makes an effective piston to propel debris from

a patent apical foramen. Since reciprocating instruments are used without any

preliminary coronal enlargement. This results in a greater engagement of flutes and,

consequently, more torque or applied pressure are needed. Also, the use of NiTi

instruments sequence can be an important factor in reducing the amount of apical

transportation and avoiding to push debris by forcing instruments apically (Gambarini

et al., 2013).

Also, according to the results of study, it can be speculated that a faster,

aggressive reciprocating system has characteristic design features, which removes a

substantial amount of dentin in a shorter period of time which was unable to coronally

displace the debris with the same efficiency as it cuts and hence poses the risk of


84

increased apical extrusion of debris. Logani and Shah in 2008 noted that preparation

with rotary system that have more No. of instruments to complete the shaping of root

canal, and provided a slower, gradual approach to the apex resulted in less AED. Yoo

and Cho in 2012 used rotary instruments (PT, Profile), hand instruments, and

reciprocating instruments (RECIPROC and WaveOne). They found that reciprocating

files remove more dentin from canal wall than rotary and hand.

Although Mtwo file and RECIPROC file have an identical S-shaped cross

sectional design with sharp cutting edges, Mtwo file produce significantly less AED

than RECIPROC file. Also, RPT file and WaveOne file have triangular or modified

triangular cross sectional design (Burklein et al., 2012b), RPT file produce

significantly less AED than WaveOne. An increased cutting ability is usually

associated with an increased cleaning efficacy (Schafer and Vlassis, 2004;

Bonaccorso et al., 2009) but may enhance debris transportation toward the apex when

used in combination with a reciprocal motion. Contrarily, continuous rotation may

improve coronal transportation of dentin chips and debris by acting like a screw

conveyor (Burklein et al., 2012a).

4.4. Apically extruded debris of RECIPROC and WaveOne

When comparing the two reciprocating single files, the RECIPROC file was

extruded significantly higher amount of AED in comparison to WaveOne. This result

is in agreement with (Burklein et al., 2012a). Cross section of WaveOne was

changeable from tip (modified triangular convex with radial land) to (triangular convex

with neutral rake angle) near shift, While the cross section of RECIPROC was one (S-

shaped) with sharp cutting edges. So the instrument with radial land tends to burnish

the cut dentine into the root canal wall, while the instrument with positive cutting edges

seem to cut and remove dentine chips. So this may lead to increase of AED by

RECIPROC more than WaveOne (Young et al., 2007; Burklein et al., 2012b).

It must be emphasized that the result of this study should not be directly

extrapolated to the clinical situation. In keeping with other authors, it may be


85

considered that the persistence of residual pulp tissue in vital cases or the presence of

periodontal tissue or even granulation tissue in chronic periodontitis could act as

natural barriers and limit apical extrusion of debris and irrigant in vivo (Mehdi et al.,

2009; Jindal et al., 2012).

Chapter Five

Conclusions and

Suggestions

Conclusions and Suggestions Chapter Five

86

Conclusions

Under the conditions of this study, the following conclusions were

withdrawn:

1. All instrument types that were used in this study produced a measurable amount of

apically extruded debris with different values.

2. Full rotary and hand instrumentation were associated with less debris extrusion

compared with the use of reciprocating single-file system.

3. The rotary Mtwo nickel–titanium files caused the least extrusion of debris.

4. The Reciprocating RECIPROC files caused the greater extrusion of debris than the

other instruments.

Conclusions and Suggestions Chapter Five

87

Suggestions

1. Evaluate the effect of instruments on the amount of apically extruded debris with

and without apical patency.

2. Evaluate the effect of instruments on the amount of apically extruded debris with

curved roots.

3. Evaluate the amount of apical extrusion debris using other instrumentation

technique.

4. Study the effect of various irrigating solution techniques and concentrations on the

amount of apical extrusion of debris.

5. Evaluate the periapical responses using different instrumentation systems: An in

vivo study.

References

References

88

References

A

Adl A, Sahebi S, Moazami F, Niknam M. Comparison of apical debris extrusion

using a conventional and two rotary techniques. IEJ. 2009; 4(4): 135-138.

Alapati SB, Brantley WA, Iijima M, Clark WA, Kovarik L, Buie C, Liu J, Ben

Johnson W. Metallurgical characterization of a new nickel-titanium wire for rotary

endodontic instruments. J Endod. 2009; 35(11):1589-1593.

Al-Doory ZK, Al-Hashimi M. The influence of instrument application frequency on

the apical extrusion of debris using rotary ProTaper, hand ProTaper and hybrid

technique (An in vitro study). A master thesis, University of Baghdad, 2012.

Al-Hadlaq SM, Aljarbou FA, AlThumairy RI. Evaluation of cyclic flexural fatigue

of M-wire nickel-titanium rotary instruments. J Endod. 2010; 36(2):305–307.

Al-Omari MAO, Dummer PMH. Canal blockage and debris extrusion with eight

preparation techniques. J Endod. 1995; 21(3):154-158.

Ayar L, Love R. Shaping ability of ProFile and K3 rotary NiTi instruments. When

used in a variable tip sequence in simulated curved root canals. Int Endod J. 2004;

37(9):593-601. (www.ivsl.org).

Azar MR, Mokhtare M. Rotary Mtwo system versus manual K-file instruments:

efficacy in preparing primary and permanent molar root canals. IJDR. 2011; 22(2):363-

370.

Azar NG, Ebrahimi G. Apically extruded debris using the ProTaper system. Aust

Endod J. 2005; 31(1):21-23. (www.ivsl.org).

B

Beer R, Baumann MA, Kielbassa AM. Pocket atlas of endodontics, 1st ed. Thieme

Stuttgart, New York, 2006; 113-151.

http://www.ncbi.nlm.nih.gov/pubmed?term=Azar%20MR%5BAuthor%5D&cauthor=true&cauthor_uid=21891918

http://www.ncbi.nlm.nih.gov/pubmed?term=Mokhtare%20M%5BAuthor%5D&cauthor=true&cauthor_uid=21891918

References

89

Beeson TJ, Hartwell GR, Thornton JD, Gunsolley JC. Comparison of debris

extruded apically in straight canals: conventional filling versus Profile 04 Taper series

29. J Endod. 1998; 24(1):18-22.

Bellizzi R, Cruse WP. A historic review of endodontics. 1689–1963, Part III. J Endod.

1980; 6(5):576-580.

Bergenholtz G, Horsted-Bindslev P, Reit C. Textbook of endodontology, 2nd ed.

Wiley-Blackwell, 2010; Ch. 11.

Bergmans L, Van Cleynenbreugel J, Beullens M, Wevers M, Van Meerbeek B,

Lambrechts P. Progressive versus constant tapered shaft design using NiTi rotary

instruments. Int Endod J. 2003; 36(4):288–295. (www.ivsl.org).

Berutti E, Negro AR, Lendini M, Pasqualini D. Influence of manual preflaring and

torque on the failure rate of ProTaper rotary instruments. J Endod. 2004; 30(4):228-

230.

Bidar M, Rastegar AF, Ghaziani P, Namazikhah MS. Evaluation of apically

extruded debris in conventional and rotary instrumentation techniques. Calif Dent

Assoc J. 2004; 32(9):665-671.

Blum JY, Machtou P, Ruddle CJ, Micallef JP. Analysis of mechanical preparations

in extracted teeth using ProTaper rotary instruments; value of the safety quotient. J

Endod. 2003; 29(9):567-575.

Bonaccorso A, Cantatore G, Condorelli GG, Schafer E, Tripi TR. Shaping ability

of four nickel-titanium rotary instruments in simulated S-shaped canals. J Endod.

2009; 35(6):883-886.

Borges MF, Miranda CE, Silva SR, Marchesan M. Influence of apical enlargement

in cleaning and extrusion in canals with mild and moderate curvatures. Braz Dent J.

2011; 22(3):212-217.

References

90

Burklein S, Dent M, Schafer E. Apically extruded debris with reciprocating single-

file and full-sequence rotary instrumentation systems. J Endod. 2012a; 38(6):850-852.

Burklein S, Hinschitza K, Dammaschke T, Schafer E. Shaping ability and cleaning

effectiveness of two single-file systems in severely curved root canals of extracted

teeth: Reciproc and WaveOne versus Mtwo and ProTaper. Int Endod J. 2012b; 45(5):

449-461. (www.ivsl.org).

Burklein S, Tsotsis P, Schafer E. Incidence of dentinal defects after root canal

preparation: reciprocating versus rotary instrumentation. J Endod. 2013; 39(4):501-

504.

C

Carvalho-Sousa B, Costa-Filho JR, Almeida-Gomes F, Maniglia-Ferreira C,

Gurgel-Filho ED, Albuquerque DS. Evaluation of the dentin remaining after flaring

using Gates Glidden drills and Protaper rotary files. RSBO. 2011; 8(2):194-199.

Cheung GSP, Bian Z, Chen Y, Peng B, Daryell BW. Comparison of defects in

Protaper hand operated and engine driven instruments after clinical use. Int Endod J.

2007; 40(3):169-178. (www.ivsl.org).

Clauder T, Baumann MA. Protaper NiTi system. Dent Clin North Am. 2004;

48(1):87-111.

D

De-Deus G, Brandao MC, Barino B, Di Giorgi K, Fedel RA, Luna AS. Assessment

of apically extruded debris produced by the single-file ProTaper F2 technique under

reciprocating movement. Oral Surg Oral Med Oral Pathol Radiol Endod. 2010;

110(3):390-394.

Diemer F, Calas P. Effect of pitch length on the behavior of rotary triple helix root

canal instruments. J Endod. 2004; 30(10):716-718.

References

91

E

Elmsallati EA, Wadachi R, Suda H. Extrusion of debris after use of rotary nickel-

titanium files with different pitch: a pilot study. Aust Endod J. 2009; 35(2):65-69.

(www.ivsl.org).

Er K, Sumer Z, Akpynar KE. Apical extrusion of intracanal bacteria following use

of two engine-driven instrumentation techniques. Int Endod J. 2005; 38(12):871-876.

(www.ivsl.org).

F

Fairbourn DR, McWalter GM, Montgomery S. The effect of four preparation

techniques on the amount of apically extruded debris. J Endod. 1987; 13(13):102-108.

Ferraz CCR, Gomes NV, Gomes BPFA, Zaia AA, Teixeira FB, Souza-Fjlho FJ.

Apical extrusion of debris and irrigants using two hand and three engine-driven

instrumentation techniques. Int Endod J. 2001; 34(5):354-358. (www.ivsl.org).

Foschi R, Nucci C, Montebugnoli L, Marchtonni S, Breschi L, Malagnino VA,

Prati C. SEM evaluation of canal wall dentine following use of Mtwo and ProTaper

NiTi rotary instruments. Int Endod J. 2004; 37(12):832-839. (www.ivsl.org).

Froughreyhani M, Lotfi M, Rahimi S, Shahi S, Milani AS, Mehanfar N.

Evaluation of the amount of apically extruded debris using Mtwo and RaCe systems –

An in vitro study. AJB. 2011; 10(84):19637-19640.

G

Gambarini G. Rationale for the use of low torque endodontic motors in root canal

instrumentation. Endod Dent Traumatol. 2000; 16(3):95-100.

Gambarini G, Testarelli L, De Luca M, Milana V, Plotino G, Grande NM, Rubini

AG, Al Sudani D, Sannino G. The influence of three different instrumentation

techniques on the incidence of postoperative pain after endodontic treatment. Ann

Stomatol. 2013; 4(1):152-155.

http://www.ivsl.org/

References

92

Garge N, Garge A. Textbook of endodontics, 2nd ed. Jaypee Brothers' Medical

publishers (p) Ltd, New Delhi, India, 2010; chapter 12.

Gavini G, Pessoa OF, Barletta FB, Vasconcellos MAZ, Caldeira CL. Cyclic fatigue

resistance of rotary nickel-titanium instruments submitted to nitrogen ion implantation.

J Endod. 2010; 36(7):1183-1186.

Ghivari SB, Kubasad GC. Apical extrusion of debris and irrigant using two rotary

systems –A comparative study. AOSR. 2011; 1(4):185-189.

Ghivari SB, Kubasad GC, Chandak MG, Akarte NR. Apical extrusion of debris

and irrigant using hand and rotary systems: A comparative study. J Conserv Dent.

2011; 14(2):187-190.

Goerig AC, Michelich RI, Schultz HH. Instrumentation of root canals in molar using

the step-down technique. J Endod. 1982; 8(12):550-554.

Grande NM, Plotino G, Butti A, Buono L. Modern endodontic NiTi systems:

morphological and technical characteristics part 1: “new generation” NiTi systems.

Endodontic Therapy. 2005; 5(1):A-E.

Grande NM, Plotino G, Butti A, Messina F, Pameijer CH, Somma R. Cross-

sectional analysis of root canals prepared with NiTi rotary instruments and stainless

steel reciprocating files. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2007;

103(1):120-126.

Grande NM, Plotino G, Testarelli L, Gambarini G. Cyclic fatigue resistance of

nickel-titanium rotary instruments used in reciprocating or continuous motion. J

Endod. 2010; 36(3):563.

Grossman LI. Endodontics 1776–1976: a bicentennial history against the background

of general dentistry. JADA. 1976; 93(1):78-87.

References

93

Gutmann JL, Gao Y. Alteration in the inherent metallic and surface properties of

nickel-titanium root canal instruments to enhance performance, durability and safety:

a focused review. Int Endod J. 2012; 45(2):113-128. (www.ivsl.org).

H

Hamouda MMG, Tawfik HMEE, Abou-Elezz AF, Ibrahim DY. Effect of apical

patency apically extruded debris during canal enlargement using hand or rotary

instruments. Journal of American Science. 2011; 7(9):33-37.

Handysides R. Advances in clinical endodontic instruments. LLU School of

Dentistry. 2010; 22(1):26-28.

Hargreaves KM, Cohen S. Cohen's pathways of the pulp, 10th ed. St. Louis, Missouri,

2011; Ch. 8 & 9.

Hinrichis RE, Walker WA. A comparison of a mounted of apically Extruded debris

using hand piece driven Ni-Ti instrument systems. J Endod. 1998; 24(2):102-106.

Howard RK, Kirkpatrick TC, Rutledge RE, Yaccino JM. Comparison of debris

removal with three different irrigation techniques. J Endod. 2011; 37(9):1301-1305.

Huang X, Ling J, Wei X, Gu L. Quantitative evaluation of debris extruded apically

by using ProTaper Universal Tulsa rotary system in endodontic retreatment. J Endod.

2007; 33(9):1102-1105.

Hulsmann M. On the history of the root canal treatment. Endodontics. 1996; 5:97-

112.

Hulsmann M. Development of a standardized methodology for the verification of

various processing parameters and comparative in vitro study of different systems for

mechanical root canal preparation. Quintessence. 2000.

Hulsmann M, Peters OA, Dummer PMH. Mechanical preparation of root canals:

shaping goals, techniques and means. Endod Top. 2005; 10(1):30-67. (www.ivsl.org).


References

94

I

Inan U, Gonulol N. Deformation and fracture of Mtwo rotary nickel-titanium

instruments after clinical use. J Endod. 2009; 35(10):1396-1399.

Ingle JI, Bakland LK, Baumgartner JC. Endodontics, 6th ed. Be Decker Inc

Hamilton, 2008; Ch. 26.

J

Jabbar AM, AL-Hashimi MK. Shaping ability of three rotary NiTi systems: Mtwo,

K3, ProTaper, in simulated curved canals (Part I). JBCD. 2010; 22(4):1-5.

Jindal R, Singh S, Gupta S, Jindal P. Comparative evaluation of apical extrusion of

debris and irrigant with three rotary instruments using crown down technique - An in

vitro study. Journal of Oral Biology and Craniofacial Research. 2012; 2(2):105-109.

Johnson E, Lloyd A, Kuttler S, Namerow K. Comparison between a novel nickel-

titanium alloy and 508 nitinol on the cyclic fatigue life of ProFile 25/.04 rotary

instruments. J Endod. 2008; 34(11):1406-1409.

K

Karabucak B, Gatan AJ, Hsiao C, Iqbal MK. A comparison of apical transportation

and length control between EndoSequence and Guidance rotary instruments. J Endod.

2010; 36(1):123-125.

Kellow SY, Al-Hashimi WN. Evaluation of the amount of apically extruded dentin

debris using four instrumentation techniques: An in vitro study. A master thesis,

University of Baghdad, 2001.

Kim S. Modern endodontic practice: instruments and techniques. Dent Clin North Am.

2004; 48(1):1-9.

Koch K, Brave D. Real world endo: Design features of rotary files and how they affect

clinical performance. Oral Health. 2002; 92(2):39-49.

References

95

Koch K, Brave D. Endodontic synchronicity. Compend Contin Educ Dent. 2005;

26(3):218-224.

Kurtzman GM. Simplifying endodontics with EndoSequence rotary instrumentation.

JCDA. 2007; 35(9):625-628.

Kustarci A, Akdemir N, Herguner SS, Altunbasa D. Apical extrusion of intracanal

debris using two engine driven and step-back instrumentation techniques: An in vitro

study. EJD. 2008; 2:233-239.

Kustarci A, Altunbas D, Akpinar KE. Comparative study of apically extruded debris

using one manual and two rotary instrumentation techniques for endodontic

retreatment. JDS. 2012; 7(1):1-6.

Kuttler S, West J. Single file system: "the science of simplicity". Dent Today. 2012;

31(3):92-95.

L

Lambrianidis T, Tosounidou E, Tzoanopoulou M. The effect of maintaining apical

patency on periapical extrusion. J Endod. 2001; 27(11): 696-698.

Landwehr DJ. Root canal shaping using a reciprocating file system. Dent Today.

2013; 32(2):94-99.

Larsen CM, Watanabe I, Glickman GN, He J. Cyclic fatigue analysis of a new

generation of nickel titanium rotary instruments. J Endod. 2009; 35(3):401-403.

Leonardo MR, De Toledo R. Endodontic rotary systems: nickel-titanium instruments,

1st ed. Medical Arts Latin, Sao Paulo, 2002; 328.

Letters S, Smith AJ, McHugh S, Bagg J. A study of visual and blood contamination

on reprocessed endodontic files from general dental practice. Braz Dent J. 2005;

199(8):522-525.

Levy G. New instrumentation to achieve mechanically throughout the endodontic

procedure: Canal Finder. Rev Franc Endod. 1984; 3:11-18.

References

96

Li KZ, Gao Y, Zhang R, Hu T, Guo B. The effect of a manual instrumentation

technique on five types of premolar root canal geometry assessed by microcomputed

tomography and three-dimensional reconstruction. BMC Med Imaging. 2011;

11(14):1-9.

Lilley JD. Endodontic instrumentation before 1800. J Br Endod Soc. 1976; 9(2):67-

70.

Lim YJ, Park SJ, Kim HC, Min KS. Comparison of the centering ability of

WaveOne and Reciproc nickel-titanium instruments in simulated curved canals. RDE.

2013; 38(1):21-25.

Logani A, Shah N. Apically extruded debris with three contemporary Ni-Ti

instrumentation systems: An ex vivo comparative study. IJDR. 2008; 19(3):182-185.

Lopez FU, Fachin EV, Camargo Fontanella VR, Barletta FB, So MV, Grecca FS.

Apical transportation: a comparative evaluation of three root canal instrumentation

techniques with three different apical diameters. J Endod. 2008; 34(12):1545-1548.

Lumley P, Tomson P, Pertot WJ, Machtou P. Protaper-hybrid technique. Dent

Update. 2008; 35(2):110-116.

M

Malagnino VA, Grande NM, Plotino G, Somma F. The Mtwo NiTi rotary system

for root canal preparation. Roots. 2006; 3:67-70.

Mangalam S, Rao CVN, Lakshminarayanan L. Evaluation of apically extruded

debris and irrigant using three instrumentation techniques. Endodontology. 2002;

14:19-23.

Martin D, Amor J, Machtou P. Mechanized endodontics: the ProTaper system,

principles and clinical protocol. RevOdont Stomatol. 2002: 31:33-42.

Martin H, Cunningham WT. The effect of endosonic and hand manipulation on the

amount of root canal material extruded. Oral Surg. 1982; 53(6):611-613.

References

97

McKendry DJ. Comparison of balanced forces, endosonic, and step-back filing

instrumentation techniques: quantification of extruded apical debris. J Endod. 1990;

16(1):24-27.

Mehdi JA, Al-Zaka IM, Al-Obiedy A. Evaluation of apically extruded debris by

using hand and rotary Nickel-Titanium instruments. MDJ 2009; 6(4):292-298.

Mitchell RP, Baumgartner JC, Sedgley CM. Apical extrusion of sodium

hypochlorite using different root canal irrigation systems. J Endod. 2011; 37(12):1677-

1681.

Moore J, Fitz-Walter P, Parashos P. A micro-computed tomographic evaluation of

apical root canal preparation using three instrumentation techniques. Int Endod J.

2009; 42(12):1057-1064. (www.ivsl.org).

Mounce RE. The K3 NiTi files system. Dent Clin North Am. 2004; 48(1):137-157.

Myers GL, Montgomery S. A comparison of weights of debris extruded apically by

conventional filing and Canal Master techniques. J Endod. 1991; 17(6):275-279.

N

Naidorf IJ. Endodontic flare-ups: bacteriological and immunological mechanisms. J

Endod. 1985; 11(11): 462-464.

Nazari S, MirMotalebi F. A comparative study on the amount of extruded material

from the apical foramen with NiTi rotary and stainless steel hand instruments. IEJ.

2006; 1(2): 69-72.

O

Ounsi HF, Franciosi G, Paragliola R, Al Huzaimi K, Salameh Z, Tay FR, Ferrari

M, Grandini S. Comparison of two techniques for assessing the shaping efficacy of

repeatedly used nickel-titanium rotary instruments. J Endod. 2011; 37(6):847-850.

References

98

P

Pak JG, White SN. Pain prevalence and severity before, during, and after root canal

treatment: a systematic review. J Endod. 2011; 37(4):429-38.

Paque F, Zehnder M, De-Deus G. Microtomography based comparison of

reciprocating single-file F2 ProTaper technique versus rotary full sequence. J Endod.

2011; 37(10):1394-1397.

Parirokh M, Jalali S, Haghdoost AA, Abbott PV. Comparison of the effect of

various irrigants on apically extruded debris after root canal preparation. J Endod.

2012; 38(2):196-199.

Peters OA, Peters CI, Schonenberger K, Barbakow F. ProTaper rotary root canal

preparation: assessment of torque and force in relation to canal anatomy. Int Endod J.

2003; 36(2):86-92. (www.ivsl.org).

Plotino G, Grande NM, Sorci E, Malagnino VA, Somma F. A comparison of cyclic

fatigue between used and new Mtwo Ni–Ti rotary instruments. Int Endod J. 2006;

39(9):716-723. (www.ivsl.org).

R

Reddy SA, Hicks ML. Apical extrusion of debris using two hand and two rotary

instrumentation techniques. J Endod. 1998; 24(3):180-183.

Roane JB, Sabala CL, Duncanson MG. The "balanced force" concept for

instrumentation of curved canals. J Endod. 1985; 11(5):203-2011.

Ruddle CJ. The Protaper advantage: shaping the future of endodontics. Dent Today.

2001; 20:1-9.

Ruddle CJ. The Protaper technique: shaping the future of endodontic. Endod Top.

2005; 10:187-190. (www.ivsl.org).

Ruddle CJ. Endodontic canal preparation: WaveOne single-file technique. Dent

Today. 2012; 31:1-7.



References

99

Ruddle CJ, Machtou P, West JD. The shaping movement 5th generation technology.

Dent today. 2013; 32:1-8.

Ruiz-Hubard EE, Gutmann JL, Wagner MJ. A quantitative assessment of canal

debris forced periapically during root canal instrumentation using two different

techniques. J Endod. 1987; 13(12):554-558.

Rzhandov EA, Belyaeva TS. Design features of rotary root canal instruments. ENDO.

2012; 6(1):29-39.

S

Saad AY, Al-Hadlaq SM, Al-Katheeri NH. Efficacy of two rotary NiTi instruments

in the removal of gutta-percha during root canal retreatment. J Endod. 2007; 33(1):38-

41.

Schafer E, Erler M, Dammaschke T. Comparative study on the shaping ability and

cleaning efficiency of rotary Mtwo instruments: part 1—shaping ability in simulated

curved canals. Int Endod J. 2006a; 39(3):196-202. (www.ivsl.org).

Schafer E, Erler M, Dammaschke T. Comparative study on the shaping ability and

cleaning efficiency of rotary Mtwo instruments: part 2—cleaning effectiveness and

shaping ability in severely curved root canals of extracted teeth. Int Endod J. 2006b;

39(3):203-212. (www.ivsl.org).

Schafer E, Vlassis M. Comparative investigation of two rotary nickel-titanium

instruments: ProTaper versus RaCe. Part 2. Cleaning effectiveness and shaping ability

in severely curved root canals of extracted teeth. Int Endod J. 2004; 37(4):239-248.

(www.ivsl.org).

Schilder H. Cleaning and shaping the root canal. Dent Clin North Am. 1974;

18(2):269-296.

Seltzer S, Naidorf IJ. Flare-ups in endodontics: I. Etiological factors. J Endod. 1985;

11(11):472-478.

References

100

Serota ES. Seismic Wave (One™): A progressive shift in technical awareness.

Endodontic Solutions. 2012; 1-6.

Shen Y, Cheung GS, Bian Z, Peng B. Comparison of defects in ProFile and ProTaper

systems after clinical use. J Endod. 2006; 32(1):61-65.

Shen Y, Qian W, Abtin H, Gao Y, Haapasalo M. Fatigue testing of controlled

memory wire nickel-titanium rotary instruments. J Endod. 2011; 37(7):997-1001.

Siqueira JF. Microbial causes of endodontic flare-ups. Int Endod J. 2003; 36(7):453-

463. (www.ivsl.org).

Siquiria JF, Rocas IN, Favieria A. Incidence of post operative pain after intracanal

procedures based on an antimicrobial strategy. J Endod. 2004; 28(6):457-460.

Sonntag D, Ott M, Kook K, Stachniss V. Root canal preparation with the NiTi

systems K3, Mtwo and ProTaper. Aust Endod J. 2007; 33(2):73-81. (www.ivsl.org).

T

Tanalp J, Kaptan F, Sert S, Kayahan B, Bayirl G. Quantitative evaluation of the

amount of apically extruded debris using 3 different rotary instrumentation systems.

Oral Surg Oral Med Oral Pathol Oral Radiol Endo. 2006; 101(2):250-257.

Tasdemir T, Er K, Yildirim T, Celik D. Efficacy of three rotary NiTi instruments in

removing gutta-percha from root canals. Int Endod J. 2008; 41(3):191-196.

(www.ivsl.org).

Tasdemir T, Er K, Celik D, Aydemir H. An in vitro comparison of apically extruded

debris using three rotary nickel-titanium instruments. JDS. 2010; 5(3):121-125.

Tinaz AC, Alacam T, Uzun O, Maden M, Kayaoglu G. The effect of disruption of

apical constriction on periapical extrusion. J Endod. 2005; 31(7):533-535.

Torabinejad M, Kettering JD, McGraw JC, Cummings RR, Dwyer TG, Tobias

TS. Factors associated with endodontic interappointment emergencies of teeth with

necrotic pulps. J Endod. 1988; 14(5):261-266.

References

101

V

Vallabhaneni S, More GR, Gogineni R. Single file endodontics. Indian J Dent Adv.

2012; 4(2):822-826.

Vande Visse JE, Brilliant JD. Effect of irrigation on the production of extruded

material at the root apex during instrumentation. J Endod. 1975; 1(7):243-246.

Vansan LP, Pecora JD, Silva RG, Savioli RN. Comparative in vitro study of apically

extruded material after four different root canal instrumentation techniques. Braz Dent

J. 1997; 8(2):79-83.

Vaudt J, Bitter K, Kielbssa AM. Evaluation of rotary canal instruments in vitro: a

review. ENDO. 2007; 1(3):189-203.

Veltri M, Mollo A, Mantovani L, Pini P, Balleri P, Grandini S. A comparative study

of Endoflare-Hero Shaper and Mtwo NiTi instruments in the preparation of curved

root canals. Int Endod J. 2005; 38(9):610-616. (www.ivsl.org).

W

Walia H, Brantley WA, Gerstein H. An initial investigation of bending and torsional

properties of nitinol root canal files. J Endod.1988; 14(7):346-351.

Webber J, Machtou P, Pertot W, Kuttler S, West J. The WaveOne single-file

reciprocating system. International Dentistry – African edition. 2012; 2(1):26-36.

Weine FS. Endodontic Therapy, 6th ed. St. Louis: CV Mosby, 2004.

West J. Progressive taper technology: rationale and clinical technique for the new

Protaper Universal system. Endod Top. 2006; 25(12):64-69 (www.ivsl.org).

Wildey WL, Senia ES. A new root canal instrument and instrumentation technique: a

preliminary report. Oral Surg Oral Med Oral Pathol. 1989; 67(2):198-207.

Wildy WL, Senia S, Montgomery S. Another look at root canal instrumentation. Oral

Surg. 1992; 74(4):499-507.

References

102

Wittgow WC, Sabiston CB. Microorganisms from pulpal chambers of intact teeth

with necrotic pulp. J Endod. 1975; 1(5):168-171.

Wu MK, Fan B, Wesselink PR. Leakage along apical root fillings in curved root

canals. Part I: effects of apical transportation on seal of root fillings. J Endod. 2000;

26(4):210-216.

Y

Yared G. Canal preparation using only one NiTi rotary instrument: preliminary

observations. Int Endod J. 2008; 41(4):339-344. (www.ivsl.org).

Yared G. Canal preparation using one reciprocating instrument without prior hand

filing: A new concept. International Dentistry – African edition. 2012; 2(2):78-87.

Yared G. Canal preparation of the MB2 canal with the R25 RECIPROC® instrument

without prior hand filing or glide path. Endodontic Courses. 2013; 1-8.

Yoo Y, Cho Y. A comparison of the shaping ability of reciprocating NiTi instruments

in simulated curved canals. RDE. 2012; 37(4):220-227.

Young GR, Parashos P, Messer HH. The principles of techniques for cleaning root

canals. Aust Dent J. 2007; 52(1):552-563. (www.ivsl.org).

Z

Zarrabi MH, Bidar M, Jafarzadeh H. An in vitro comparative study of apically

extruded debris resulting from conventional and three rotary (Profile, Race,

FlexMaster) instrumentation techniques. JOS. 2006a; 48(2):85-88.

Zarrabi MH, Bidar M, Jafarzadeh H, Talati A. The influence of instrument

application frequency on apical extrusion of debris in three instrumentation techniques.

JDS. 2006b; 3(2):1-7.

DENTSPLY. ProTaper Universal Brochure. 2006; 1-4. (www.dentsplymea.com).


http://www.dentsplymea.com/sites/default/files/ProTaperUniversal4pp%20Brochure_1.pdf

http://www.dentsplymea.com/

References

103

VDW. Mtwo® -The efficient NiTi system- User information. 2011; 1-28. (www.vdw-

dental.com).

VDW. RECIPROC® one file endo- User information. 2012; 1-32. (www.vdw-

dental.com).



Appendices

104

Appendices

Appendix I: Amount of apically extruded debris for Group I.

Sample No. Pre-

instrumentation

weight (in g)

Post-

instrumentation

weight (in g)

Weight of AED

(in mg)

1-1 9.90093 9.90190 0.97

1-2 10.14389 10.14454 0.65

1-3 9.77645 9.77708 0.63

1-4 9.81704 9.81762 0.58

1-5 9.86767 9.86844 0.77

1-6 9.88684 9.88748 0.64

1-7 9.78178 9.78244 0.66

1-8 10.04208 10.04277 0.69

1-9 9.93164 9.93232 0.68

1-10 9.87196 9.87290 0.94

1-11 10.05428 10.05536 1.08

1-12 9.66351 9.66410 0.59

1-13 9.98976 9.99043 0.67

1-14 9.87983 9.88049 0.66

1-15 10.01496 10.01581 0.85

105

Appendix II: Amount of apically extruded debris for Group II.

Sample No. Pre-

instrumentation

weight (in g)

Post-

instrumentation

weight (in g)

Weight of AED

(in mg)

2-1 9.90124 9.90223 0.99

2-2 9.71149 9.71216 0.67

2-3 10.18977 10.19044 0.67

2-4 9.76331 9.76406 0.75

2-5 9.94655 9.94712 0.57

2-6 9.71774 9.71838 0.64

2-7 10.09565 10.09628 0.63

2-8 9.90095 9.90160 0.65

2-9 9.70065 9.70162 0.97

2-10 10.01051 10.01140 0.89

2-11 9.79537 9.79606 0.69

2-12 9.63045 9.63104 0.59

2-13 9.57844 9.57910 0.66

2-14 9.88625 9.88682 0.57

2-15 9.86268 9.86368 1.00

106

Appendix III: Amount of apically extruded debris for Group III.

Sample No. Pre-

instrumentation

weight (in g)

Post-

instrumentation

weight (in g)

Weight of AED

(in mg)

3-1 10.06335 10.06424 0.89

3-2 9.95190 9.95252 0.62

3-3 9.74292 9.74340 0.48

3-4 9.98319 9.98408 0.89

3-5 10.07026 10.07072 0.46

3-6 9.81865 9.81906 0.41

3-7 9.61474 9.61537 0.63

3-8 9.92468 9.92530 0.62

3-9 9.61553 9.61604 0.51

3-10 9.96507 9.96576 0.69

3-11 9.89826 9.89897 0.71

3-12 9.88334 9.88387 0.53

3-13 9.76285 9.76337 0.52

3-14 9.79720 9.79774 0.54

3-15 10.31039 10.31089 0.50

107

Appendix IV: Amount of apically extruded debris for Group IV.

Sample No. Pre-

instrumentation

weight (in g)

Post-

instrumentation

weight (in g)

Weight of AED

(in mg)

4-1 9.84855 9.84939 0.84

4-2 9.58132 9.58269 1.37

4-3 9.68307 9.68445 1.38

4-4 10.14772 10.14857 0.85

4-5 9.82622 9.82736 1.14

4-6 9.87861 9.87991 1.30

4-7 9.89092 9.89176 0.84

4-8 9.53368 9.53460 0.92

4-9 9.69307 9.69386 0.79

4-10 9.05976 9.06058 0.82

4-11 9.82553 9.82648 0.95

4-12 10.06852 10.06945 0.93

4-13 10.07616 10.07708 0.92

4-14 9.83480 9.83559 0.79

4-15 10.08391 10.08506 1.15

108

Appendix V: Amount of apically extruded debris for Group V.

Sample No. Pre-

instrumentation

weight (in g)

Post-

instrumentation

weight (in g)

Weight of AED

(in mg)

5-1 9.84175 9.84242 0.67

5-2 10.00440 10.00526 0.86

5-3 9.72259 9.72355 0.96

5-4 10.13308 10.13383 0.75

5-5 9.92680 9.92765 0.85

5-6 9.86809 9.86872 0.63

5-7 10.08778 10.08894 1.16

5-8 9.86692 9.86802 1.10

5-9 9.71035 9.71141 1.06

5-10 9.68789 9.68855 0.66

5-11 10.09363 10.09435 0.72

5-12 9.83185 9.83255 0.70

5-13 9.93964 9.94080 1.16

5-14 9.77929 9.78044 1.15

5-15 9.69670 9.69731 0.61

الخالصة

خالل لقناةل الميكانيكي دعدادإلل تستخدم أو الترددية الدوارةو باليد، المحمولة والتقنيات األدوات من مختلفة أنواع

قييملت الدراسة هذه من الغرض. القنوات خارج الحطام دفعتو تنتج قد والتقنيات األدوات هذه .الجذر قناة دعالجات

تيبر )البرو يتانيومت نيكلمصنودعة من الال اللبية األدوات من أنواع خمسة ستخدامإب اقمي مقذوفال الحطام كمية

ون(. الويف ،الرسبروك ،األمتو الدوار ،البروتيبر الدوار ،اليدوي

رت كل األسنان قص .حديثا المقلودعة السفلي الفك واحكمن ض سن بشري نووسبع الدراسة خمسة هذه في ستخدمأ

الجذر دخالإ تم ثم. (قارورة) ةنيثا زجاجة جمع الحطام الموزونة سابقا داخل قنينة إدراجتم ملم. 14إلى طول

مادةب الخارجي سطحال من القارورة تغليف تم ذلك، بعد .جمع الحطام نينةق من( الوسط في) مطاطية سدادة داخل

خمسة إلى دعشوائيا الجذور تقسيم تم .مطاطيةال سدادةلا خالل( 25سايمق) تنفيسال إبرة أدخلت ثم ي،المطاطالسد

:دعينه تحتوي دعلى خمسة دعشر مجمودعة كل مجمودعات،

.)مجمودعة أولى: أدعدت بواسطة نظام البروتيبر اليدوي )تقنية اليد

الدوران الكامل(. : أدعدت بواسطة نظام البروتيبر الدوار )تقنيةةمجمودعة ثاني

.)مجمودعة ثالثة: أدعدت بواسطة نظام األمتو الدوار )تقنية الدوران الكامل

تقنية الترددية(.الالمبرد الواحد ) يذ الرسبروكمجمودعة رابعة: أدعدت بواسطة نظام

تقنية الترددية(.الالمبرد الواحد ) يذ ويف ون: أدعدت بواسطة نظام الخامسةمجمودعة

حركات إدخال ثالثة بعد أو (المبارد اليدوية والدوارة)من مبردحجم كل بعد المقطر الماء من ملم 1 ستخدامإ تم

الحطام جمع تم. 15بواسطة مبرد نوع كي حجم مصونةظلت نفوذية القناة .(المبارد الترددية)ن موإخراج

الحطام معج نينةتم تجفيف ق القناة، إدعداد نهاية في ثم جمع الحطام الزجاجية. قنينة في القمي الثقب من مقذوفال

ضعهاو ثم ومن جافة، القنينة ظهرت حتى سادعة نصف كل القنينة فحص وتم مئوية درجة 111 دعلى الفرن ستخدامإب

الفرق لها. طةالمتوس القيمة حسابتم و قنينة، لكل متتالية أوزان ثالثة دعلى الحصول تم .كامال التجفيفه مجفف في

اد دعدإ خالل القمي الثقب من مقذوفال حطامال من الوزن يمثل( الوزن بعدما و الوزن قبل ما) ينةقنال أوزان بين

.اةالقن

جميع أن النتائج وأظهرت(. (LSDوال (ANOVA) ال ختباراتإ باستخدام إحصائيا البيانات تحليل تم قدل

ن م إحصائيا ةمتوسط قيمة أقل لديها )الثالثة( األمتو الدوار مجمودعةكانت و الحطام، قذفحثت دعلى المجمودعات

وتيبر اليدويثم البر ،البروتيبر الدوار )الثانية(مجاميع ها تتل األخرى، الفئات جميع معمقارنة قميا مقذوفال حطامال

مةقي أدعلى لديهاكانت )الرابعة( الرسبروك مجمودعة أن حين فيدعلى التوالي. )الخامسة( والويف ون ،)األولى(

ل بشك الدوران الكامل واألدوات ذات اليدوية أكثر من األدواتحطاما ة أنتجت األدوات الترددي .إحصائياتوسطة م

.ملحوظ

خارج الجذر قميا قذوفمال حطامالكمية تقييم

لتحضير قناة الجذر مختلفة أنظمة ستخدامإب

الجامعة المستنصرية / سناناأل طب كلية مجلس لىإ مقدمة رسالة

األسنان معالجة في الماجستير درجة نيل متطلبات من كجزء

من قبل

عين حسينهاشم م سنانواأل الفم وجراحة طب لوريوسابك

بأشراف

يمان محمد الزقةإ أ.م الدكتورة

ماجستير معالجة أسنان

م2013 ه4143 أيلول / شوال /

evaluation of the amount of apically extruded debris using different root canal instrumentation...

Documents

university of al

college of dentistry

almustansiriyah university

assistant professor

iman mohammed alzaka

rotary protaper

scientific support

continuous assistance