Adelaide Dental School, The University of Adelaide, Adelaide, Australia.
Eur J Orthod. 2023 Nov 30;45(6):868-874. doi: 10.1093/ejo/cjad054.
The objective of this study was to examine the relative contributions of genetic and environmental influences on variation in dental arch form in individuals who have largely completed their craniofacial growth.
The subjects of this study comprised dental casts of 50 monozygotic twins and 24 dizygotic twins from the collection of records of twins housed at the Adelaide Dental School, Australia. The subjects were of Western European descent, with an average age of 20.93 ± 5.58 years. Dental casts were scanned using a 3D scanner to analyse the dental arch form. Landmark-based inter-arch and intra-arch measurements were performed. Structural equation modelling was employed to analyse the quantitative data using the normal assumptions of the twin model.
Genetic modelling revealed that additive genetic and unique environmental factors best explained the observed variation for all occlusal traits measured, except for mandibular intercanine width. High heritability was observed for most intra-arch occlusal variables (0.61-0.85) including the maxillary and mandibular intercanine and intermolar widths, arch depth and perimeter. In contrast, moderate heritability was found for inter-arch occlusal variables (0.52-0.59) such as overjet and overbite. Sexual dimorphism was evident, with males displaying larger posterior arch width than females (P < 0.05).
Our sample was limited to individuals of Western European ancestry.
The predominant source of occlusal variation within this group of Australian twins of Western European descent was controlled by genetic effects, and most were highly heritable. Generally, intra-arch occlusal variables showed greater heritability compared with inter-arch occlusal variables.
本研究旨在探讨遗传和环境因素对颅面生长基本完成的个体牙弓形态变异的相对贡献。
本研究的对象为澳大利亚阿德莱德牙科学院记录双胞胎收藏中的 50 对同卵双胞胎和 24 对异卵双胞胎的牙模。研究对象为西欧血统，平均年龄为 20.93±5.58 岁。使用 3D 扫描仪扫描牙模，以分析牙弓形态。进行基于标志点的牙弓间和牙弓内测量。采用结构方程模型，根据 twin 模型的正态假设分析定量数据。
遗传建模显示，加性遗传和独特环境因素最佳解释了所测量的所有咬合特征的观察到的变异，除了下颌间牙宽度。大多数牙弓内咬合变量（0.61-0.85）具有高度遗传性，包括上颌和下颌间牙和磨牙宽度、牙弓深度和周长。相比之下，牙弓间咬合变量（0.52-0.59）的遗传度适中，如覆颌和覆盖。存在性别二态性，男性的后牙弓宽度大于女性（P<0.05）。
我们的样本仅限于西欧血统的个体。
在这群具有西欧血统的澳大利亚双胞胎中，牙弓内的咬合变异主要受遗传因素控制，且大多数具有高度遗传性。总体而言，牙弓内的咬合变量比牙弓间的咬合变量具有更高的遗传性。
