Prevalence of Permanent Three-rooted Mandibular First Molars Using Cone-beam Computed Tomography Imagings in an Iranian Population

Abstract

Having the knowledge of root canal system anatomy is essential for success of endodontic treatment, and lack of such knowledge may lead to treatment failure. Lack of recognition of root canal configuration, improper cleansing and obturation, as well as additional root in mandibular first molar which is caused by super imposition,that is not usually detectable in routine radiographs, and in some cases the dentistEs lack of awareness of the anatomy of teeth leads to failure in endodontic treatment. As a result, it is necessary to pay more attention to the root anatomy of such teeth. The aim of this study is using Cone-Beam Computed Tomography with 3D images, which is an easy and exact way for the analysis of root morphology with regard to common radiographs,to evaluate the prevalence of three rooted mandibular first molar in an Iranian population. Materials and Methods: 384 CBCTs from subjects reffering to oral and maxillofacial radiology department of dental faculty of Tabriz University of Medical Sciences in order to take CBCT as a part of routine examination diagnosis and treatment planning from 2011-2013 were selected for this study and the cases with well-developed permanent mandibular first molar apices were included. The 3D images were reconstructed in axial cross sections and evaluated by two endodontists for the presence of three-rooted mandibular first molar with an extra lingual root (Radix Entomolaris) or an extra buccal root (Radix Paramolaris). Results: The distribution of three-rooted mandibular first molar with an additional distoligual root in an Iranian population is 3%, the incidence of which was 3.53% for women and 2.50% for men. There was not a significant relationship between gender and bilateral occurrence of three-rooted mandibular first molar. Conclusion: CBCT is an effective tool for the detection of additional distolingual roots and it is a valuable aid for dentists performing root canal treatment. The results of this study and similar studies indicate that racial differences play a significant role in the occurrence of three-rooted mandibular first molar.