[Comparison of coronal microleakage of canals filled with gutta percha and resilon with a glass ionomer coronal barrier]

Coronal seal is as important as the quality of root canal therapy in treatment success. This study aimed to compare the coronal microleakage of canals filled with Resilon and gutta percha with a glass ionomer coronal barrier In this experimental study, the crowns of 64 single-rooted human premolar teeth were cut at the level of CEJ. Root canals were prepared using rotary ProTaper files. The teeth were randomly divided into 4 experimental groups [n=14] and 2 positive and negative control groups [n=8]. Root canals of experimental group specimens were filled with gutta percha [groups 1 and 2] or Resilon [groups 3 and 4] using lateral condensation technique. The roots of negative control specimens were filled and all teeth surfaces were sealed with sticky wax. Root canals of positive controls were filled without the application of sealer. Glass ionomer coronal barrier was placed at the orifices in groups 2 and 4. Microleakage of Streptococcus faecalis was evaluated during 90 days. Data were analyzed using Chi square, Log-Rank and Tukey's tests The degree of microleakage was less in groups with GI coronal barrier. However, this difference was not statistically significant [P>0.05]. Time to microleakage in gutta percha+ coronal barrier and Resilon+ coronal barrier groups was significantly less than that in gutta percha and Resilon groups, respectively [P=0.03]. Within the limitations of this study, microleakage occurred in all groups but glass ionomer acted as an effective barrier

[Comparing the effectiveness of Gutta-Percha and Resilon removal using two different techniques in endodontic retreatment]

Background: The goal of nonsurgical retreatment is the removal of all filling materials to completely disinfect the whole root canal space. Recently Resilon obturating system has been introduced as a root canal filling material

Objective: To compare Gutta-percha and Resilon removal, using ProTaper rotary files with chloroform or heat in endodontic retreatment

Methods: This experimental study was performed on sixty-four human single-canal lower jaw extracted premolars at Dental School, Qazvin University of Medical Sciences during 2010. Following separating teeth crowns from the cementoenamel junction, canals were instrumented using step-back technique with k-files. Later, the extracted teeth were randomly divided into four groups of 16 teeth. Canals were obturated with either gutta-percha/AH26 [groups 1,2] or Resilon/Epiphany [groups 3,4]. Retreatment for groups 1 and 3 was performed with ProTaper system and heat and for groups 2 and 4 with ProTaper system and chloroform using crown-down technique. Once the retreatment procedure was completed and justified, roots were sectioned longitudinally and examined under stereomicroscope. Data were analyzed using T-test, Kruskal- Wallis, and Mann-Whitney tests

Findings: In all groups, some filling materials [core material and sealer] were seen on the canal walls. Although, amount of Gutta-Percha/AH26 and Resilon/Epiphany system residue were similar, the amount of residual materials in group 4 was significantly more than other groups [P<0.05]. Furthermore, the amount of residual materials in group 3 was more than group 1 in the coronal third of canals [P<0.05]. The time required to remove filling material in group 2 was significantly higher than those of other groups [P<0.05]

Conclusion: According to our findings, Resilon, like Gutta-percha, is re-treatable. However, none of these two materials could be completely removed from root canal walls