A Study of Anatomic Characteristics of Distolingual Root of Permanent Mandibular Molars in Taiwanese Population

Abstract

＂Background＂: There are some morphological variants that may have a negative impact on the periodontal disease progression and treatment outcome. However, parts of these variants were found with racial predilection. The purpose of this study was to investigate the prevalence and anatomic characteristic of the distolingual root in the mandibular molar area in Taiwanese population through computed tomography images. ＂Material and Methods＂: Subjects were patients receiving mandibular computed tomography between 2011 and 2013 at Chi-Mei medical center. Those with missing teeth on both sides or with prosthesis with were excluded. Total 261 patients with computed tomography images of the mandibular molar teeth were included in the study. With 3-D image reconstruction software, the prevalence of the distolingual root, the roots length and the root trunks length of bilateral mandibular molar were measured and analyzed. ＂Results＂: The prevalence rate of disto-lingual root was 13.96% for the mandibular first molar and 0.77% for the mandibular second molar; the prevalence rate in the first molar was significantly higher than that in the second molar (p＜0.0001). Concurrent incidence on both sides of the first molar accounted for 7.35%. The distal root trunk was significantly longer than buccal and lingual root trunks (p＜0.0001). The disto-buccal root was significantly longer than the disto-lingual root (p＜0.05). The distal furcation was closer to the lingual side (p＜0.05). ＂Conclusion＂: The prevalence rate of disto-lingual rootof the mandibular first molar was obviously higher in the Taiwan population than in other regions and it helped with the understanding of anatomic morphological variants. The importance should not be ignored in the clinical setting.