A Comparative Study Between Resilon and Gutta-Percha as a Secondary Root Canal Filling Materials: An In Vitro Study

INTRODUCTION: Adequate root canal seal following retreatment is essential for a successful outcome. Resilon/Epiphany (R/E) obturation system has been introduced as a substitute for conventional gutta-percha/sealer method. This in vitro study compared the amount of apical microleakage of R/E with gutta-percha/AH26 (GP/AH26) sealer as secondary root canal filling following retreatment in human teeth. MATERIALS AND METHODS: Fifty human single-rooted lower premolar teeth were selected. After preparing them with ProTaper rotary NiTi instruments, all the canals were obturated using GP/AH26 sealer. After 10 days, all the samples were retreated using the same rotary NiTi instruments. The samples were divided randomly into two experimental groups A and B (n=20) and positive and negative control groups (n=5). In group A, all canals were obturated using GP/AH26 sealer and in group B all canals were obturated using R/E. After one week incubation in 37˚C with 100% humidity, the amount of apical microleakage was evaluated with fluid filtration model. All the apical microleakage data were analyzed with Mann-Whitney U test.  RESULTS: The mean amounts of apical microleakage were 0.317 ± 0.287 and 0.307 ± 0.281 µL/8min (fluid pressure=30 cm H2O) in experimental group A and B respectively; the difference was not statistically significant (P>0.05). CONCLUSION: R/E seems to be a good alternative for retreatment as a secondary root canal filling material. However, Resilon/Epiphany obturation system does not completely avert microleakage

Anatomy of Permanent‎ ‎Mandibular‎ First‎ Molars in a Selected Iranian Population Using ‎Cone-beam Computed Tomography

Introduction: Knowledge of radicular anatomy has a crucial impact on endodontic practices. Since some anatomic features such as modifications of Vertucci are not evaluated adequately, this study was conducted. Methods and Materials: In this in vivo study, cone-beam computed tomography (CBCT) images of‎ 312‎ intact bilateral first‎ molars‎ from‎ 156‎ patients‎ (‎79‎ ‎males‎ and‎ 77‎ females with an average age of ‎35.58‎±‎11.17‎ years‎)‎ were‎ investigated by a trained dentist in terms of number‎ of‎ roots,‎ number‎ of‎ canals‎ in‎ each‎ root‎ and‎ in‎ ‎each‎ tooth,‎ and shapes‎ of‎ canals‎ according‎ to‎ Vertucci’s‎ classification‎ and‎ its‎ modifications.‎ Groups were compared using the Chi-square test. The level of significance was set at 0.05. Results: Of all teeth, 5.2%‎ had‎ 3‎ roots.‎‎ ‎Mesial‎ roots‎ had‎ mostly‎ 2‎ canals‎ while distal roots had a similar frequency of 1 and 2 canals.‎ ‎Of‎ all‎ teeth,‎ ‎‎39.7%‎ had‎ 3‎ canals,‎ 45.2%‎ had‎ 4‎ canals,‎ 13.8%‎ had‎ 5‎ canals,‎ and‎ 1.3%‎ had‎ 6‎ canals.‎ There were no significant differences between males and females, ‎in terms of number of roots (P=0.137), number of canals in mesial (P=0.453) or distal roots (P‎‎=0.328), and total number of canals (P=0.138).‎ The most frequent Vertucci classes in mesial and distal roots were IV ‎‎followed‎ by‎ II and I‎, respectively. There were no significant differences between males and females in terms of Vertucci classes of mesial (P=0.211) or distal (P=0.205) roots. Conclusion: In this population, there were 3 to 6 canals per tooth (mostly 4 and 3 canals).‎ Males and female’s ‎might be similar regarding the number of roots, or number of canals in each root, number of ‎canals in each tooth, or the predominant canal shape in each root.Keywords: Anatomy;‎ Cone-beam Computed Tomography; Endodontics;‎ Root Anatom