北京大学学报（医学版）2018，Vol.50Issue(2)：271-278,8.DOI:10.3969/j.issn.1671-167X.2018.02.012
探索成人正畸前后下颌三维数字化模型的重叠方法
Exploring a new method for superimposition of pre-treatment and post-treatment mandibular digital dental casts in adults
摘要
Abstract
Objective:To explore a cone beam computed tomography (CBCT)-independent method for mandibular digital dental cast superimposition to evaluate three-dimensional (3D) mandibular tooth movement after orthodontic treatment in adults,and to evaluate the accuracy of this method.Methods:Fifteen post-extraction orthodontic treatment adults from the Department of Orthodontics,Peking University School and Hospital of Stomatology were included.All the patients had four first premolars extracted,and were treated with straight wire appliance.The pre-and post-treatment plaster dental casts and craniofacial CBCT scans were obtained.The plaster dental casts were transferred to digital dental casts by 3D laser scanning,and lateral cephalograms were created from the craniofacial CBCT scans by orthogonal projection.The lateral cephalogram-based mandibular digital dental cast superimposition was achieved by sequential maxillary dental cast superimposition registered on the palatal stable region,occlusal transfer,and adjustment of mandibular rotation and translation obtained from lateral cephalogram superimposition.The accuracy of the lateral cephalogram-based mandibular digital dental cast superimposition method was evaluated with the CBCT-based mandibular digital dental cast superimposition method as the standard reference.After mandibular digital dental cast superimposition using both methods,3D coordinate system was established,and 3D displacements of the lower bilateral first molars,canines and central incisors were measured.Differences between the two superimposition methods in tooth displacement measurements were assessed using the paired t-test with the level of statistical significance set at P ＜ 0.05.Results:No significant differences were found between the lateral cephalogram-based and CBCT-based mandibular digital dental cast superimposition methods in 3D displacements of the lower first molars,and sagittal and vertical displacements of the canines and central incisors;transverse displacements of the canines and central incisors differed by (0.3 ± 0.5)mm with statistical significance.Conclusion:The lateral cephalogram-based mandibular digital dental cast superimposition method has the similar accuracy as the CBCT-based mandibular digital dental cast superimposition method in 3D evaluation of mandibular orthodontic tooth displacement,except for minor differences for the transverse displacements of anterior teeth.This method is applicable to adult patients with conventional orthodontic treatment records,especially the previous precious orthodontic data in the absence of CBCT scans.关键词
下颌骨/正畸学,矫正/牙移动/牙模型/成像,三维Key words
Mandible/Orthodontics, corrective/Tooth movement/Dental models/Imaging, three-dimensional分类
医药卫生引用本文复制引用
戴帆帆,刘怡,许天民,陈贵..探索成人正畸前后下颌三维数字化模型的重叠方法[J].北京大学学报（医学版）,2018,50(2):271-278,8.基金项目
北京大学医学-信息科学交叉学科种子基金项目(BMU20140438)资助 Supported by the Peking University Seed Fund for Medicine-Information Interdisciplinary Research Project (BMU20140438) （BMU20140438）
