ABSTRACT
Background: One of the main reasons for the failure of root canal treatment is the incomplete knowledge of the root canal system. With respect to the complexity of maxillary molars root canal system, and the possibility of the relationship between the buccolingual width of the mesiobuccal root and root canal morphology in maxillary molars, the aim of this study is to determine this relationship with cone-beam computed tomography (CBCT). Materials and Methods: This in vitro study carried out on 311 CBCT scans. Maxillary first molars (n = 311) were evaluated in three sagittal, axial, and coronal planes. For each tooth the number of canals, presence of second mesiobuccal (MB2), buccolingual width of mesiobuccal root at the cementoenamel junction (CEJ), and mid-root level, and type of canals according to the Vertucci's classification were determined. Results: The results showed that 49.1% of first maxillary molars had 3 and 50.8% had four root canals. The most common canal type in the mesiobuccal root was Vertucci's Type I followed by Types II, IV, and V. The prevalence of MB2 in the Iranian subpopulation was 50.1%. In maxillary first molars with MB2, the buccolingual width of mesiobuccal root at the CEJ and mid-root level (P < 0.001) was significantly greater than the corresponding values in other one without MB2. Conclusion: The results showed that the buccolingual width of mesiobuccal root in maxillary first molars at the CEJ level and mid-root was correlated with the number of root canals.
ABSTRACT
OBJECTIVES: This study aimed to compare the transportation of the mesiobuccal canal of maxillary molars following root canal preparation with HyFlex CM (HCM) and Edge Taper Platinum (ETP) rotary systems and stainless steel (SS) hand files using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: This in-vitro study was performed on 48 maxillary molars in three groups of 16. The teeth were mounted in acrylic blocks, and root canals were prepared using HCM in group 1 (up to #30/0.06), ETP in group 2 (up to F3/0.06), and SS hand files in group 3 (up to #30). CBCT scans were taken before and after root canal preparation. The amount of canal transportation was measured at 0, 3, 6, and 9mm from the apex. Data were analyzed using Kruskal-Wallis and Mann-Whitney tests. RESULTS: The difference in canal transportation at 0 and 6mm from the apex was significant between the HCM and ETP groups (P=0.031 and 0.023) but none of the systems showed any significant difference with hand files at 0-and 6-mm levels (P=0.10, 0.56, 0.22, and 0.50), respectively. At 3mm from the apex, no significant difference was noted among the groups (P=0.30). At the 9-mm level, the amount of canal transportation was not significantly different between HCM and ETP (P=0.83) but they showed significant differences with hand files (P<0.001). CONCLUSION: ETP and HCM caused less canal transportation at the curvature of the mesiobuccal canal of maxillary molars compared to hand files. ETP showed superior efficacy in root canal preparation compared to HCM.
