obturation of the root canal systems

Obturation of the root canal systems

Assoc.Prof.Dr. Siriwan Suebnukarn D.D.S., Ph.D.

Grad.Dip.Clin.Sci. (Endodontics)

Faculty of Dentistry, Thammasat University

[email protected]

Outline

Part I

1. Need for obturation

2. Timing of obturation

3. Evaluation of obturation

Part II

4. Methods of obturation

5. Procedural errors

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Obturation and treatment outcome

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Outline

Part I

1. Need for obturation2.1 Bacterial infection in pulpal and periradicular disease2.2 Healing of periapical lesion after cleaning and shaping2.3 Bacteria remaining after cleaning and shaping2.4 Creating bacteria-tight seal of the root canal



Part II


5. Procedural errors6

1.1 Bacterial infection in pulpal and periradicular disease

The primary etiology of pulpal and periradicularpathosis is bacteria. Kakehashi S, Stanley HR, Fitzgerald RJ. The effects of

surgical exposures of dental pulps in germ-free and conventional laboratory rats. Oral Surg Oral Med Oral Pathol. 1965;20:340-349.

Möller AJ, Fabricius L, Dahlén G, Ohman AE, Heyden G. Influence on periapical tissues of indigenous oral bacteria and necrotic pulp tissue in monkeys. Scand J Dent Res. 1981 Dec;89(6):475-84.

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1.1 Bacterial infection in pulpal and periradicular disease (Kakehashi et al., 1965)

Germ-free rats

Pulp exposure

Reparative response

No devitalized pulp

No apical granuloma

No abscess formation

Conventional rats

Pulp exposure

No evidence of repair

Severe pulpal inflammation

Complete pulp necrosis

Granuloma

Abscess formation

Aim: To observe the pathologic changes resulting from untreated experimental pulp exposures in germ-free rats as compared with conventional rats with a normally complex microflora.

Methods: The pulp tissues of these rats were exposed by drilling through the occlusal surface of the maxillary right first molar with a carbide round bur. After varying postoperative time intervals (1 to 42 days), the animals were killed and the appropriate tissues were serially sectioned.

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Results: By the eighth day, vital pulp tissue remained only in the apical half of the roots in the conventional animals. Complete pulpal necrosis with granulomas and abscess formation occurred in all older specimens. In contrast, no devitalized pulps, apical granulomas, or abscesses were found in the germ-free animals.

Conclusions: These results, even in the face of gross food impactions, indicate that the presence or absence of a microbial flora is the major determinant in the healing of exposed rodent pulps.

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1.1 Bacterial infection in pulpal and periradicular disease (Möller et al., 1981)

Aseptically necrotized teeth

Immediately sealed

No inflammatory reaction in the apical tissue clinically, radiographically, and

histologically

Aseptically necrotized teeth

Sealed after 6-7 days

Inflammatory reaction in the apical tissue clinically, radiographically, and

histologically

Aim: To study the influence on periapical tissues of indigenous oral bacteria and necrotic pulp tissue in monkeys

Methods: In nine monkeys (Macaca fascicularis) the pulps of 78 teeth were aseptically necrotized. Twenty-six of the pulp chambers were kept bacteria-free by sealing, while 52 were infected by the indigenous oral flora.

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Results: The results were recorded clinically, radiographically and microbiologically at the beginning of the experiment and after 6-7 months. The final examination also included histologic recordings.

Conclusions: It was shown that noninfected necrotic pulp tissue did not induce inflammatory reactions in the apical tissues. By contrast, teeth with infected pulp tissue showed inflammatory reactions clinically and radiographically.

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1.2 Healing of periapical lesion after cleaning and shaping

14Weine, 2003

15Jumpita, 2013

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1.3 Bacteria remaining after cleaning and shaping

3-D image shows the enamel, dentin, and root canal with surface rendering from Micro-CT (Li et al., 2011).

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Pre-preparation canal systems are in green.Post-preparation canal systems are in red (Li et al., 2011).

Images of unshaped (A) and prepared (B) systems reconstructed from micro computed tomography data (Peters et al., 2003)


Prepared canal areas indicated by green colour (Peters et al., 2003).



Bacteria and bacterial byproducts remaining in the inaccessible areas of a cleaned and shaped canal system could initiate a lesion because the host defense mechanisms are unable to remove them.

This may lead to a recurrence of the lesion.

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21Weine, 2003

1.4 Creating bacteria-tight seal

To create bacteria-tight seal from coronal canal orifice to the apical part of the root canal.

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Original WL, LT TMC FRC

FRC Restoration Recall1 Recall2

1.4 Creating bacteria-tight seal

One of the main principles for successful root canal treatment is the prevention of microorganisms and toxins from the oral flora penetrating through the root canal system into the periapical tissues.

This is achieved by obturating the root canal system completely, including the coronal and apical ends.

A number of studies have indicated that leakage, whether from a coronal or apical direction, adversely affects the success of root canal treatment (Wu et al., 2000; Torabinejad et al., 1990).

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Apical leakage - Wu et al., 2000

Ledge 2 mm from apex 3 mm from apexleakage no leakage

Coronal leakage - Torabinejad et al., 1990 Forty-five root canals were cleaned, shaped, and then obturated with gutta-percha and root canal sealer, using a lateral condensation technique in vitro.

The coronal portions of the root filling materials were placed in contact with Staphylococcus epidermidis and Proteus vulgaris.

Over 50% of the root canals were completely contaminated after 19-day exposure to S. epidermidis, and after 42-day exposure to P. vulgaris.

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Outline

Part I



2.1 Vital pulp

2.2 Necrotic pulp

2.3 Single- versus multiple-visit endodontic treatment


Part II



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Timing of obturation

Factors influencing the appropriate time to obturatea tooth are;

1. The pulp and periapical status1. Vital pulp

2. Necrotic pulp

2. The degree of difficulty and patient management

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Root canal treatment procedure

http://www.youtube.com/watch?v=jHHn52KhBkQ

2.1 Vital pulp

One-visit root canal treatment is acceptable in cases where the patient exhibits a vital pulp.

Removal of the normal or inflamed pulp tissue and performance of the procedure under aseptic conditions should result in a successful outcome because of the absent or small amount of bacteria contamination.

Obturation at the initial visit also prevent contamination as a result of leakage during the period between patient visits (multiple-visit root canal treatment).

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2.1 Vital pulp

Symptomatic (painful) irreversible pulpitis needs removal of the inflamed pulp (which is the pain source). Obturation may be completed at the same appointment.

However, treatment of these problem requires caution because of difficulties in management of a patient in pain.

If the patient presents with severe symptoms and the diagnosis is symptomatic apical periodontitis or abscess, obturation is contraindicated. Emergency treatment is needed.

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2.1 Vital pulp

2.2 Necrotic pulp

Patients who present with pulp necrosis with or without asymptomatic periapical pathosis (chronic apical periodontitis, chronic apical abscess, condensing osteitis) may be treated in one visit.

When patients present with acute symptoms caused by pulp necrosis and acute periapicalabscess, obturation is delayed until the patient is asymptomatic.

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2.3 Single- versus multiple-visit endodontic treatment Mechanical debridement combined with antibacterial

irrigation (0.5% sodium hypochlorite) can render 40–60% of the treated teeth bacteria-negative (Bystrom & Sundqvist 1983, Sjogren et al. 1997).

In addition to mechanical debridement and antibacterial irrigation, dressing the canal for 1 week with calcium hydroxide has been shown to increase the percentage of bacteria-negative teeth to around 70% (Law & Messer 2004).

Thus, the healing rate of multiple-visit treatment should be higher than single-visit treatment (without calcium hydroxide dressing).

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Study Sample

size

S1

(%)

S2

(%)

S3

(%)

Orstavik et al., 1991 23 95.7 56.7 34.8

Sjogren et al., 1991 18 100 50 0

Yared & Bou Dagher, 1994 60 100 100 31.7

Shuping et al., 2000 40 97.5 40 7.5

Peters et al., 2002 21 100 14.3 71.4

Kvist et al., 2004 44 95.5 63.6 36.4

McGurkin-Smith et al., 2005 27 92.6 51.9 18.5

Waltimore et al., 2005 18 100 100 33.3

Positive culture


Sathorn C, Parashos P, Messer HH. Effectiveness of single- versus multiple-visit endodontic treatment of teeth with apical periodontitis: a systematic review and meta-analysis. Int Endod J. 2005 Jun;38(6):347-55.

Figini L, Lodi G, Gorni F, Gagliani M. Single versus multiple visits for endodontic treatment of permanent teeth: a Cochrane systematic review. J Endod. 2008 Sep;34(9):1041-7.

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Sathorn et al., 2005

AIM: Does single-visit root canal treatment without calcium hydroxide dressing, compared to multiple-visit treatment with calcium hydroxide dressing for 1 week or more, result in a lower healing (success) rate (as measured by clinical and radiographic interpretation)?

REVIEW METHODS: The included studies were randomized controlled clinical trials (RCTs) comparing healing rate of single- and multiple-visit root canal treatment in humans. The outcome measured was healing of radiographically detectable lesions. 38

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Based on the current best available evidence, single-visit root canal treatment appeared to be slightly more effective than multiple visit, i.e. 6.3% higher healing rate. However, the difference in healing rate between these two treatment regimens was not statistically significant (p = 0.3809).

Sathorn et al., 2005

Figini et al., 2008

OBJECTIVES: To assess the difference in short- and long-term complications between single- and multiple-visit RCT.

SELECTION CRITERIA: Randomized controlled trials of patients needing RCT were included. The outcomes considered were the number of teeth extracted for endodontic problems; radiological success after at least 1 year, that is, absence of any periapical radiolucency; postoperative pain; painkiller use; swelling; or sinus track formation.

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Figini et al., 2008

MAIN RESULTS:

Twelve randomized controlled trials were included in the review.

The frequency of radiological success and immediate postoperative pain were not significantly different between single- and multiple-visit RCT.

Patients undergoing single-visit RCT reported a higher frequency of painkiller use and swelling, but the results for swelling were not significantly different between the two groups.

We found no study that included tooth loss and sinus track formation among its primary outcomes.

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Outline

Part I



3. Evaluation of obturation3.1 Post-obturation evaluation

3.2 Evaluation of the treatment outcome

Part II



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3.1 Post-obturation evaluation

The presence of signs and symptoms for a few days after obturation is common due to tissue irritation from the procedure.

Radiographic findings Uniform density from coronal to apical aspect

Extension of the material to the prepared length

Continuous tapering from coronal to apical regions

Proper permanent or temporary restoration

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Criteria for endodontic success Clinical

No abnormal signs and symptoms

Radiographic Normal contour and width of PDL

Intact lamina dura

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Dynamic of healing

Healed (Success)

Healing

Persistence

Function

Disease (Failure)

45Friedman and Mor, 2004

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HealingHealed

A. Immediate post-operative radiograph of two maxillary incisors with apical periodontitis.

B. At 9 months, both teeth demonstrate reduced radiolucencies. Termination of a study at this end-point would result in both teeth being recorded as showing signs of healing.

C. At 18 months, both teeth are healed. Termination of a study at this end-point would result in both teeth being recorded as completely healed.

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HealingHealed

A. Immediate post-operative radiograph of mandibular first molar with extensive apical periodontitis.

B. At 18 months, most of the original lesion has healed, but a small radiolucency remained about the mesial root tip. The tooth was recorded as ‘‘incomplete healing’’.

C. Two years later (at 3.5 years) the entire lesion has completely healed. If the follow-up period were extended to 4 years, this tooth would have been recorded as healed.

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Healed

A. Mandibular lateral incisor with apical periodontitis and associated apical external resorption.

B. At one year, the radiolucency is completely resolved and the tooth is symptom free, indicating it has healed.

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Persistence

A. Maxillary lateral incisor with apical periodontitis.

B. Immediate post-operative radiograph.

C. At 1 year, the tooth is symptom free but the radiolucency has not been reduced, indicating persistence of the original disease.

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Function

A. Mandibular first molar with extensive apical periodontitis.

B. Clinical view of gingival recession, coupled with probing depth apical to the root tips, suggests total loss of the buccalbone plate. Prognosis is poor.

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Function

D and E. Immediate post-operative radiograph after root canal therapy, followed by placement of a resorbable guided tissue regeneration membrane.

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Function

F and G. At 6 months, the radiolucency is considerably reduced and the gingival tissue appears to be healed. Although the prognosis remains poor, the tooth being functional achieves the goals of therapy as set by the patient.

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A. Immediate post-operative radiograph of mandibular first premolar with apical periodontitis.

B. At 7 months, the clearly reduced radiolucency is indicative of the healing in progress.

C. At 2 years, the radiolucency has grown larger again beyond its original size, indicative of reversal of the healing process and subsequent regression.

DiseaseFailure

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DiseaseFailure

Outline

Part I




Part II



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Rationale for using gutta percha

1. Lateral condensation

2. Vertical condensation

3. Thermoplasticized gutta percha Injection technique

4. Thermoplasticized gutta percha carried on a solid core

5. Thermocompaction technique

6. Solvent technique

7. Others 56

GuttaPercha

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Rationale for using gutta percha

Effect of original shape of the canal and canal preparation Some canals are irregular in shape

Oval canals of mandibular anterior teeth

Figure-eight canals of single-rooted maxillary premolars

Kidney-bean canals of distal root of mandibular molars

The different types of instruments used in canal preparation produce different general shapes.

Reaming will result in a circular shape.

Filing gives an elliptical shape when viewed in cross section.

Semisolid materials can be compacted and forced into an irregularly shaped of the prepared cavity.

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Gutta percha-Advantages

Becomes plastic when warmed and compactabiliy After heating, gutta-percha could be packed with

pluggers, and injected using thermoplastic techniques.

Inertness Almost the least reactive of all the materials used in

clinical dentistry

Tissue tolerance Embedding gutta-percha in the rat periodontium

Dimensional stability Almost no dimensional change after condensation

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Gutta percha-Advantages

Radiopacity Gutta-percha is radiopaque and therefore is easily

recognizable on a dental x-ray film

Has solvents Gutta-percha can be dissolved by Chloroform and

xylene to allow for re-treatment or solvent obturation technique.

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Gutta percha-Disadvantages

Lack of rigidity Gutta-percha will bend easily makes it difficult to use in

the smaller sizes (i.e., less than 30).

Lack of length control

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Methods of obturation

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4.1 Lateral Condensation

Applicable to most root canals which have a continuously tapered funnel canal preparation with an apical matrix in sound dentin.

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A standard gutta-percha master cone was fitted to the working length and exhibited a “tug back” sensation.

The sealer was mixed according to the manufacturer’s instructions and introduced into the canal by using a K-file operated by hand in a counterclockwise rotation.

The tip of the master cone was coated with the sealer and seated into position.

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Lateral compaction was accomplished using a spreader that was able to reach within 1 mm of the working length.

Accessory gutta-percha cones were added and similarly compacted.

The process was completed when the spreader could not penetrate more than 3 mm into the canal.

Finally, excess gutta-percha was removed with a hot plugger.


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Ref:Pathway of the pulp

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4.2 Vertical Condensation

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Down packing

A plugger with a rubber stop was selected to fit 3-mm short of the working length without binding. Other pluggers were chosen for the middle and coronal portions of the canal.


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Down packing

A non-standardized tapered gutta-percha cone exhibiting a “short, crisp” tug-back sensation at 0.5 mm short of the working length was chosen.

A thin coat of sealer was applied to the root canal walls to the approximate depth of the master cone by using a file.

The master cone was lightly coated with sealer at its apical one third and placed into the root canal.


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The tip of an activated heat carrier, Touch’n Heat (Analytic Technology, Redmond, WA), was introduced to sear off the gutta-percha at the orifice; the material was then compressed vertically with a prefitted (cold) plugger.

The process was repeated with the compaction being done more apically with a prefitted smaller plugger each time.


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Back packing

After packing of gutta-percha was done with the last plugger (completion of the down pack),

back-filling of the canal was achieved by a 2-3 mm segment of gutta-percha without sealer or,

injection of thermoplasticized gutta-percha, each time injecting a 3- to 4-mm segment and compacting the increment with a prefitted plugger.


4.3 Thermoplasticized gutta perchainjection technique

Obtura II - High temperature 185-200oC

Ultrafil - Low temperature 70-90oC77

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Prepare the prefitted pluggers

Lightly coat the walls of the root canal system with a small amount of root canal sealer.

Needle tip is inserted to the junction of middle third and apical third.

Passively inject guttapercha

Compact gutta percha with the prefitted pluggers


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4.4 Thermoplasticized gutta perchacarried on a solid core

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Select the appropriate size of Thermafil obturator to correspond with the size of the MAF file.

Lightly coat the walls of the root canal system with a small amount of root canal sealer.

Set the silicone stop on the Thermafil point to the correct working length. Heat the Thermafil in the oven.

Take the obturator from the oven and insert to the working length without twisting or rotation.

Use the bur to separate the handle from the carrier.

4.4 Thermoplasticized gutta perchacarried on a solid core

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4.5 Thermocompaction

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4.5 Thermocompaction

Rotary compactor using low speed and low temp alpha-phase gutta percha (Quickfill)

Rapid frictional heat softens the gutta-percha and causes it to flow into the space the carrier occupied. Select Quickfill 2 sizes smaller than MAF

Position rotary compactor short of WL

Start clockwise rotation and press apically using light pressure

4.6 Solvent technique

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4.6 Solvent technique

Solvent techniques involve the total or partial dissolution of gutta-percha in solvents, primarily chloroform or eucalyptol. Chloropercha Eucapercha

Chloropercha is used as a sealer

The master cone is dipped into the chloroperchaand then vertically condensed into the canal apex.

The problem is that gutta-percha shrinks away from the walls as the solvents evaporate. Extensive leakage is generally seen with these techniques.

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Resilon and Epiphany

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Resilon and Epiphany

Recent studies have shown that the new obturation system was able to create a monoblock that prevents bacterial leakage in vitro and in vivo, and it increases the fracture resistance of the filled roots.

Resilon (Resilon Research LLC, Madison, CT), and Epiphany root canal sealant (Pentron Clinical Technologies, Wallingford, CT)

Jia WT, Trope M, Alpert B. Dental filling material. United States Patent & Trademark Office. United States Patent Application 20050069836, March 31, 2005.

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Resilon master cone was fitted to the working length of with tug back.

The Epiphany self-etching primer was placed into the root canal with a microbrush, and the excess primer was removed with paper points.

The Resilon master cone was coated with Epiphany sealer and placed into the canal.

The material was down packed by using the continuous wave condensation technique with the System B heat source at a temperature of 150°C and a power setting of 10.

Backfilling was performed with a Resilon pellet in an Obtura II unit at a temperature of 140°C. After backfilling, the coronal surface of the root filling was light cured for 40 seconds.

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Mineral Trioxide Aggregate

Mineral Trioxide Aggregate

Immature teeth necrosis exhibiting pulp necrosis were treated with calcium hydroxide to establish an apical barrier before obturation.

Mineral Trioxide Aggregate (Pro Root, Dentsply-Tulsa Dental) can be used as an apical barrier material before obturation.

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Outline

Part I




Part II


5. Procedural errors5.1 Vertical root fracture

5.2 Extrusion of filling material

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5.1 Vertical root fracture

The roots of 54 extracted human mandibular incisors were instrumented, measured, and then filled with gutta-percha by lateral condensation on an Instron testing machine until vertical root fracture occurred.

A spreader load as smallas 1.5 kg (3.3 lb) produceda fracture, and 13% of thesample fractured at a loadof 3.5 kg (7.7 lb) or less (Holcomb et al., 1987).

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5.1 Vertical root fracture

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The defense resources of the periapical tissues are apparently capable of overcoming the effects of instrumentation, but cements and root canal filling materials in the periapical tissues cause persistence of inflammation (Seltzer et al., 1973).



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obturation of the root canal systems

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