正畸治疗前后腭皱的法医同一认定研究

Model analysis of palatal rugae morphology before and after orthodontic treatment in forensic identification

目的利用腭皱模型分析法评价腭皱形态的个体独特性及正畸治疗前后腭皱形态的稳定性,探索腭皱形态在法医齿科学个体识别应用中的可靠性。方法分别收集70例正畸治疗前、后的上颌模型。通过模型测量分析对腭皱形态及个体识别进行检测,包括数量、方向、形状及长度的变化和近、远中侧端点分别在近远中向及前后方向上的位移。同时对正畸治疗前、后及正畸治疗后与其复制后腭皱模型进行配对检测,计算其平均正确配对率(%)。结果 (1)正畸治疗后腭皱数量、方向、形状及长度均有变化,表现为长度变化(28.6%);分裂(4.3%);联合(2.9%);方向变化(1.4%);形状变化(1.4%)。并且治疗后腭皱远中端点的前后向位移变化占45.7%,近远中向位移占40%;而腭皱近中端在在前后向和在近远中向上位移变化分别为32.9%和17.1%。(2)正畸治疗前组及正畸治疗后组不同个体均未发现相同的腭皱模式。(3)正畸治疗前、后模型的腭皱平均正确配对率为92.19%。而治疗后模型与复制后模型的腭皱平均正确配对率是99.05%。结论腭皱形态具有高度的个体特异性,尽管正畸治疗后腭皱的形态有一定变化,但仍可作为一种新的方法应用于法医齿科的同一认定。

Objective To evaluate the palatal rugae individual-specific properties and stability before and after orthodontic treatments for investigating the reliability of palatal rugae for individual identification of forensic dentistry based on the palatal rugae model ananlysis. Methods Maxillary models of 70 patients were obtained before and after orthodontic treatments respectively. Palatal rugae morphologic changes and individual identification were examined by model analysis including changes in number, orientation, shape, and length of palatal rugae, as well as mesial and distal endpoint displacement in the anterioposterior（AP） and mesiodistal（MD） direction. Furthermore, The examination of palatal rugae average match accuracy（%） was performed between the pre-treatment and post-treatment orthodontics models and post-treatment and duplicated post-treatment orthodontics models. Results（1） The palatal rugae morphological changes were found and the incidence of palatal rugae changes were showed in length（28.6%）, segmentation（4.3%）; unification（2.9%）; orientation（1.4%） and shape（1.4%） after orthodontic treatment. Also the displacement of the distal endpoint of palatal rugae was 45.7% for anterioposterior indirection, 40% for mesiodistal indirection after orthodontic treatment, while the anterioposterior displacement of the mesial endpoint of palatal rugae was 32.9% and mesiodistal displacement was 17.1%.（2） The identical palatal rugae patterns were not found both the pre-treatment and post-treatment groups.（3） The palatal rugae average match accuracy was 92.19% between pre-treatment and posttreatment groups, however, the rate had increased by 99.05% when matching the palatal rugae patterns of post-treatment groups to their duplicates. Conclusion Palatal rugae patterns have the high specific properties to each individual. Although there are some changes in morphology of palatal rugae after orthodontic treatment, it still can be used as a novel method for individual identification in forensic dentistry.