Department of Oral Anatomy, School of Dentistry, Aichi Gakuin University, Nagoya, Japan.
Department of Periodontology, School of Dentistry, Aichi Gakuin University, Nagoya, Japan.
J Periodontal Res. 2020 Oct;55(5):753-761. doi: 10.1111/jre.12764. Epub 2020 May 25.
Little is known about the anatomical characteristics of root morphology in molars lost due to periodontal reason. The aim of this study was to study root morphology in maxillary and mandibular molars lost due to periodontitis by investigating the frequency of root fusion, classifying fusion types, and measuring radicular groove depth by micro-computed tomography.
Ninety-eight posterior teeth were collected from 87 Japanese patients during the study period. Of these, maxillary (N = 36) and mandibular (N = 22) second molars lost most frequently were assessed for root fusion and morphology.
The 36 maxillary second molars included nine (25%) teeth with a single root, 14 (39%) with two roots, and 13 (36%) with three roots. Of the 23 maxillary second molars with fused (1 and 2) roots, there were 11 (48%), 2 (9%), 1 (4%), 1 (4%), 3 (13%), and 5 (22%) teeth with root types 1-6, respectively. The 22 mandibular second molars comprised 14 (64%) teeth with a single root, 7 (32%) with two roots, and one (4%) with three roots. Of the 14 mandibular second molars with a fused (1) root, 12 (86%) had a C-shaped root and two (14%) had a non-C-shaped root.
We observed a higher frequency of root fusion in the present study compared with that reported by previous studies using randomly selected second molars.
关于因牙周原因丧失的磨牙的牙根形态的解剖学特征知之甚少。本研究旨在通过微计算机断层扫描研究因牙周炎丧失的上颌和下颌磨牙的牙根形态,调查牙根融合的频率,对融合类型进行分类,并测量根沟深度。
在研究期间,从 87 名日本患者中收集了 98 颗后牙。其中上颌(N=36)和下颌(N=22)第二磨牙因牙周炎丧失的情况最为常见,用于评估牙根融合和形态。
36 颗上颌第二磨牙中,有 9 颗(25%)为单根牙,14 颗(39%)为双根牙,13 颗(36%)为三根牙。在 23 颗融合(1 和 2 根)的上颌第二磨牙中,分别有 11 颗(48%)、2 颗(9%)、1 颗(4%)、1 颗(4%)、3 颗(13%)和 5 颗(22%)的牙齿属于根型 1-6。22 颗下颌第二磨牙中,有 14 颗(64%)为单根牙,7 颗(32%)为双根牙,1 颗(4%)为三根牙。在 14 颗融合(1 根)的下颌第二磨牙中,有 12 颗(86%)为 C 形根,2 颗(14%)为非 C 形根。
与以往使用随机选择的第二磨牙进行的研究相比,本研究观察到更高频率的牙根融合。