RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES,

KARNATAKA, BANGALORE.

PROFORMA FOR REGISTRATION OF SUBJECTS FOR DISSERTATION.

1. NAME OF THE CANDIDATE & ADDRESS:

DR. VINNY SARA VARGHESE M.S. RAMAIAH DENTAL COLLEGE AND HOSPITAL, BANGALOREBANGALORE - 560054MOBILE NO:- 9945673604

2. NAME OF THE INSTITUTION: M.S. RAMAIAH DENTAL COLLEGE AND HOSPITAL, BANGALORE.

3. COURSE OF STUDY & SUBJECT:

MASTER OF DENTAL SURGERY CONSERVATIVE DENTISTRY AND ENDODONTICS

4. DATE OF ADMISSION TO COURSE:

10 TH MAY 2010

5. TITLE OF THE TOPIC:

COMPUTED TOMOGRAPHIC EVALUATION OF TWO ACCESS CAVITY LOCATIONS ON THE PERI-CERVICAL DENTIN AND ITS EFFECT ON INSTRUMENTATION IN MANDIBULAR ANTERIOR TEETH.

6. BRIEF RESUME OF THE INTENDED WORK

NEED FOR THE STUDY :

The conventional endodontic access cavity preparation on mandibular anterior teeth located near the cingulum of the crown requires the removal of much of the central part of the tooth, which compromises the Peri- Cervical dentin, greatly reducing the resistance of the tooth to stress. The Peri-Cervical dentin lies near the alveolar crest and extends roughly 4 mm above the crestal bone and 4 mm apical to crestal bone.

This has led to a debate about the merits of the straight line access in mandibular anterior teeth, with a new dimension being added by the greater importance being given to the conservation of Peri-Cervical dentin and there is very little literature available on the same.

Hence the purpose of this study is to evaluate the effect of access cavity location & its design on the distribution of Peri-Cervical dentin & instrumented root canal surface in mandibular anterior teeth using CT.

6.2REVIEW OF LITERATURE:

In a study done on the effect of access cavity location & design on degree &

distribution of instrumented root canal surface in maxillary anterior teeth, 30 teeth

were divided into 3 groups and were prepared using the different access cavity

designs ( lingual cingulum, lingual conventional, incisal straight line) ,and it was

seen that the incisal access cavity allowed better instrumentation1.

A radiographic study done on 279 mandibular incisor , to find an ideal endodontic

access in mandibular incisors, showed that the ideal access of most of the

mandibular incisors was not obtained with a lingual approach but an incisal straight

line access2.

In the study done on the influence of different access cavity designs on the fracture

strength in endodontically treated mandibular anterior teeth ,about 36 teeth were

taken and divided into 3 groups. The teeth were prepared using the different access

cavity designs ( lingual cingulum, lingual conventional, incisal straight line),

obturated and tested for fracture resistance in the universal testing machine and it

was seen that the incisal access cavity design allowed for better tooth conservation

and reduced the risk for fracture3.

In a study in which CT evaluation of canal preparation was done , about 30 teeth

were instrumented using rotary & hand Ni Ti instruments ( An in vitro study),

remaining dentin thickness was assessed & it was concluded that Pro Taper should

be used judiciously as it causes thinning of root dentin in coronal and middle third

of the tooth4.

The article on different access cavity preparation designs titled, modern molar

endodontic access and directed dentin conservation, the importance of the

Peri -Cervical dentin in the conservation of the tooth structure & its preservation

was been stressed upon5.

6.3 OBJECTIVE OF THE STUDY:

1. To determine the effect of access cavity design & location on the amount of Peri-Cervical dentin using CT.

2. To determine the effect of access cavity design and location on the distribution of instrumented root canal using CT.

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7.1

7.2

MATERIALS & METHODS:

SOURCE OF THE DATA :

Materials:

30 freshly extracted human permanent mandibular incisors with mature

apices 10%formalin

Dentsply Endodontic access cavity preparation burs

Micro motor

Endodontic explorer

Size 10 K file

Protaper universal instrument system

3% NaOCl

26 gauge needle

RC Prep

Acrylic blocks

METHOD OF COLLECTION OF DATA:

SAMPLE SIZE:

30 human mandibular anterior teeth that have been freshly

extracted for therapeutic reasons will be taken.

Exclusion criteria:

Teeth with cervical abrasion, immature apices, previous restorations or endodontic

manipulation, calcifications, fractures or crack, internal or external resorption and

dilacerations are excluded.

The selected teeth will be divided into two groups:

GROUP A: Conventional access cavity preparation-15 teeth

GROUP B: Incisal access cavity preparation -15 teeth

SCANNING & IMAGING:

Tissue fragments and calcified debris will be removed from the

teeth and they will be stored in 10% formalin solution. The teeth will be then split

into two groups and stored as group A & group B with 15 teeth in each group.

Both the groups will be scanned using CT, pre operatively before

instrumentation. Levels will be chosen for evaluation in the CT. Sectioning will be

started at 1 mm from the apex up to coronal orifice. The images will be stored in the

computer's hard disk for further comparison between pre instrumentation and post

instrumentation data.

Group A : The initial point of entry with the bur will be in the centre of the lingual

surface of the crown , just coronal to the cingulum. The bur will be held at right

angles to the long axis of the teeth, the opening will be enlarged until the cavity is

extended minimally to remove the entire pulp chamber roof cervico-incisally and

mesio-distally.

Group B: The initial point of entry with the bur will be short of the incisal edge in

the lingual surface of the crown , with the bur being held parallel to the long axis of

the tooth. The opening will be enlarged holding the bur parallel to the long axis of

the tooth.

Then the Group 1 & Group 2 teeth will be prepared using a set of

ProTaper instruments (Dentsply Maillefer). Canals will be prepared using torque

control endodontic hand piece (X smart rotational speed 250 r.p.m.). The entire

specimens will be prepared according to the manufacturer's recommendation. The

canals will be considered to be finished when F1 reaches the full WL (D1 diameter

0.25 mm). Canals will be irrigated with3% NaOCl after each instrument, delivered

by means of a 26 gauge needle, allowing for adequate back flow. RC prep lubricant

7.3

7.4

will be used throughout the procedure.

Post instrumentation, the teeth will be then scanned under the same

conditions as the initial scan. Data will be stored. Following instrumentation, the pre

operative and postoperative CT reconstructions will be superimposed for each group

at all the levels and the canal circumferences will be traced. Narrow

communications between canals will be excluded. The canal centre is to be

determined by the pixel measures & then the images will be superimposed using the

canal center as reference.

STATISTICAL ANALYSIS:

Descriptive statistics for continuous data will be expressed in mean standard

deviation or a median and quarter range.

Normality of the data will be tested using Shapiro Wilk test. If the data is normal

student ‘t’ test will be used to compare the two groups. Otherwise non parametric

Mann Whitney U test will be used.

Does the Study require any investigation or intervention to be conducted on

patients or other human or animal? If so, please describe briefly.

No, the study does not require any investigation or intervention on humans, as it is

an ex vivo study.

Has Ethical clearance been obtained from your institution in case of above?

Not applicable.

8. REFERENCES:

1. G. Mannan, E. R. Smallwood& K Gulabivala .Effect of access cavity location &

design on degree & distribution of instrumented root canal surface in maxillary

anterior teeth. International Endodontic Journal 2001; 34: 176-83.

2. Michael J. Mauger, Rodney M. Ware, Joel B. Alexander and William G.

Schindler. Ideal Endodontic Access in Mandibular Incisors.

Journal of Endodontics 1999; 25-3: 206-07.

3. Young-Gyun Lee, Hye-Jin Shin, Se-Hee Park, Kyung-Mo Cho, Jin-Woo Kim .

The influence of different access cavity designs on the fracture strength in

endodontically treated mandibular anterior teeth.

Journal of Korean Academy of Conservative Dentistry 2004; 29(6): 515-19.

4. Shruthi Nagaraja , B.V.Sreenivasa Murthy. CT evaluation of canal preparation

using rotary & hand Ni Ti instruments: An in vitro study. Journal of

Conservative Dentistry 2010;13-1: 16-22 .

5. David Clark, John Khademi. Modern Molar Endodontic Access and Directed

Dentin Conservation. Dental Clinics of North America 2010; 54: 249–73.

6. Ingle’s Text book of Endodontics 6th edition, 2009.

9. SIGNATURE OF THE CANDIDATE:

10.

REMARKS OF THE GUIDE:

11.

NAME AND DESIGNATION OF:

11. (1) GUIDE:

11. (2) SIGNATURE:

DR. JOHN V. GEORGEPROFESSOR,DEPARTMENT OF CONSERVATIVE DENTISTRY AND ENDODONTICS.

11. (3) CO-GUIDE:

11. (4) SIGNATURE:

11. (5) HEAD OF THE DEPARTMENT:

11. (6) SIGNATURE:

DR. B.V. SREENIVASA MURTHYPROFESSOR AND HOD,DEPARTMENT OF CONSERVATIVE DENTISTRY AND ENDODONTICS.

12.

12. (1) REMARKS OF THE CHAIRMAN AND PRINCIPAL

12. (2) SIGNATURE: