Apical Extrusion of Thermoplasticized Obturating Material in Canals Instrumented with Profile 0.06 or Profile GT

Non-surgical Endodontic Management of Multiple Mishaps: A Case Report

The description of non-surgical retreatment is to eliminate all previous filling materials and correct any mishaps. An adequate understanding of root and canal morphology is a fundamental requirement for obtaining a favorable outcome in endodontic treatment. The endodontic diagnosis was previously treated through therapy with symptomatic apical periodontitis. Treatment was performed under a dental operative microscope. Gates Glidden (GG) drills size 2 and 3 were used to remove the coronal part of gutta-percha for all canals. A braiding technique with a Hedstrom file size 15 without a solvent was used to remove gutta-percha and separate the file together for the palatal canal whereas the mesiobuccal canal was retreated by ProTaper Retreatment Kit. Proper understanding of root canal morphology and using an endodontic armamentarium could reduce endodontic mishaps. This case report described the successful management of overextended gutta-percha, a separated file, and a missed canal.

The effect of canal preparation on fill length in straight root canals obturated with GuttaCore

INTRODUCTION

A common critique of using thermoplasticized carrier-based obturators is the incidence of overextension. It would be of benefit to clinicians to have a technique for canal preparation that would allow for predictable length control. This study compared straight canals instrumented to a size 40 file using a 0.04 standardized taper preparation (STP) and a varied taper preparation (VTP) by evaluating the extension of GuttaCore (GC) obturators (Dentsply Tulsa Dental, Tulsa, OK).

METHODS

Eighty extracted mature human premolars with single straight canals were randomly divided into 2 experimental groups (n = 40). The STP group was instrumented to size 40/.04 at the working length (WL). The VTP group was instrumented to size 40/.02 at the WL. Both groups were obturated with a size 40 GC obturator. Extension of the material, in relation to the WL, was evaluated and assessed ordinally. Statistically significant differences were determined by a 2-group chi-square test with a 2-sided P value set at P = .05 and a Fisher exact test of equal proportions.

RESULTS

Significant differences in extrusion existed between the STP and VTP groups when controlling for the type of apical preparation (P = .0005). The STP group resulted in a 47.2% incidence of overextension, whereas the VTP group resulted in 10.5% overextension of obturating material.

CONCLUSIONS

The results indicate that when filling straight canals with GC obturators the canal can be instrumented using a varied tapered canal preparation with a low likelihood of overextension.

Lack of correlation between obturation limits and apical leakage

The aim of this paper was to evaluate a possible correlation between obturation limits and leakage. Thirty-six extracted human mandibular incisors were used, characterized by straight and single canals, non-anatomical complexities, absence of previous endodontic treatment, complete root formation and patent foramen. For standardization of the specimens for the leakage analysis, foraminal instrumentation was performed up to a Flexofile #25 (Dentsply-Maillefer, Ballaigues, Switzerland). All specimens were instrumented and filled following the same protocol, and the obturation limits were measured using Axiovision 4.5 Software (Carl Zeiss Vision, Hallbergmoos, Germany). The specimens were then separated into three groups (n=12) according to the following variables: Group I--obturation limits ranging from 0 mm to 0.76 mm of the main apical foramen. Group II--obturation limits ranging from 0.77 mm to 0.98 mm of the main apical foramen. Group III--obturation limits ranging from 0.99 mm to 1.68 mm of the main apical foramen. Apical leakage was quantified by fluid filtration. The analyses were confronted using Pearson's test (p>0.05). Groups I, II and III showed Pearson correlation values (r2) of -0.152, -0.186 and 0.058, respectively. No correlation was found between the obturation limits and apical leakage.

A 1-year follow-up study on leakage of single-cone fillings with RoekoRSA sealer

OBJECTIVE

The aim of this study was to measure long-term leakage along single cone (SC) fillings.

STUDY DESIGN

Two groups of canines (n = 30) were prepared and a size 55 file was the apical master file. Step-back was performed using files of sizes 60, 70, and 80. The canals were filled by the single cone technique using RoekoRSA as sealer. To place sealer into each canal, a bidirectional spiral was used in 1 group, whereas a gutta-percha cone was used in the other group. Immediately after root filling, the coronal portion of root filling was removed by postspace preparation. Leakage along the 4 mm remaining apical root filling was measured after 1 week and again after 1 year using a fluid transport model. Ten additional canine roots were prepared and filled with gutta-percha cones without sealer, serving as positive controls. Occurrence of apical extrusion of materials was recorded.

RESULTS

The apical root filling in all 60 canine roots did not show leakage either at 1 week or at 1 year. All 10 positive controls showed gross leakage (>20 muL/h). In no case gutta-percha extruded through the apical foramen. Sealer extruded apically in 88% of the roots where a gutta-percha cone was used to introduce sealer, whereas in 28% of the roots where a bidirectional spiral was used to introduce sealer (by chi-square test, P < .05).

CONCLUSION

In wide and straight canals, SC fillings with RoekoRSA sealer prevented fluid transport for 1 year. Using bidirectional spiral to place sealer reduced sealer extrusion under the conditions of this experiment.