Analysis of root canal system and the consistency between maxillary first and second molars in a Taiwanese population: a CBCT study

Objectives The aim of this study was to use cone-beam computed tomography (CBCT) to analyze the morphology and similarity / symmetry of root canal systems in the maxillary first and second molars in Taiwanese. Materials and methods A total of 519 patients in the dental department of NTUH from January 2014 to December 2014 were enrolled. Overall, CBCT images of 1741 maxillary molars were blindly examined by two endodontists to analyze the correlation of root canal systems between the first molars and second molars as well as the bilateral first or second molars. Results The most common type in Taiwanese maxillary first molars is 3R4C (3 roots/4 canals), whereas in maxillary second molars is 3R3C.The symmetry of root canal system in bilateral maxillary first and second molars were found in 87.36% and 79.85%,respectively. The similarities of root canal system in adjacent maxillary first and second molars were 53.07% in right side and 52.58% in left side. The concurrence of MB2 canal in bilateral maxillary first molars is 77.8%, whereas is 35.97% in maxillary second molars. In the 110 patients MB2 canal in bilateral maxillary second molars, the chances of bilateral MB2 canals in their maxillary first molar is almost 100%. Conclusions Maxillary first molars have higher prevalence of 3R4C root canal system than maxillary second molars. The symmetry and similarity were higher in bilateral maxillary homonym molars than in adjacent maxillary molars. These information and assessing CBCT images in advance provide a totally understandings of the whole root canal system, and improve the endodontic treatment outcome efficiently.