Private practice, Belém, Pará, Brazil; Department of Orthodontics, Federal University of Pará, Belém, Pará, Brazil.
Department of Orthodontics, School of Dentistry, Federal University of Goiás, Goiânia, Goiás, Brazil.
Am J Orthod Dentofacial Orthop. 2020 May;157(5):619-630. doi: 10.1016/j.ajodo.2019.05.016.
This study aimed to examine the role of dentofacial morphology in discriminating semi-isolated indigenous groups. These populations present a similar pattern of dietary habits. Studies in human genetics have reported a large intertribal genetic distance and low intratribal variation.
This study was conducted following the Strengthening the Reporting of Observational Studies in Epidemiology guidelines. Face dimensions were measured through facial photogrammetry, and dental arches and tooth size were evaluated using plaster models. A total of 98 subjects in the permanent dentition and belonging to 4 indigenous groups were analyzed: Arara-Iriri (n = 20), Arara-Laranjal (n = 33), Assurini (n = 25), and Xicrin-Kayapó (n = 20). The random and systematic errors were verified using the Dahlberg formula and the intraclass correlation coefficient (ICC), respectively. In order to evaluate the discrimination of the variables to identify the indigenous groups, a discriminant analysis was performed (P <0.05).
A small causal error (Dahlberg, 0.13-1.81) and excellent replicability (ICC, 0.75-0.99) for face dimensions as well as for models (Dahlberg, 0.10-0.68; ICC, 0.94-0.99) were observed. The discriminant analysis allowed the identification of 4 populations by facial and dental arch dimensions and tooth size. Dentofacial biometry revealed an accuracy of 98% for females and 100% for males, which confirms a high intragroup homogeneity and considerable intergroup heterogeneity for dentofacial features.
Biometric measurements of the human face added with tooth size and dental arch dimensions are very useful to identify remote indigenous populations with high accuracy. Supported by previous studies in human genetics, these findings reinforce the role of genetic variation in the determination of dentofacial features.
本研究旨在探讨牙颌面形态在鉴别半孤立土著群体中的作用。这些人群具有相似的饮食习惯模式。人类遗传学研究报告称，各部落之间存在较大的遗传距离，而内部变异较小。
本研究遵循《观察性研究的报告加强规范》进行。通过面部摄影测量法测量面部尺寸，通过石膏模型评估牙弓和牙齿大小。共有 98 名恒牙期的受试者，分为 4 个土著群体：Arara-Iriri（n=20）、Arara-Laranjal（n=33）、Assurini（n=25）和 Xicrin-Kayapó（n=20）。分别使用 Dahlberg 公式和组内相关系数（ICC）验证随机和系统误差。为了评估变量的鉴别能力以识别土著群体，进行了判别分析（P<0.05）。
观察到面部尺寸以及模型的测量值具有较小的因果误差（Dahlberg，0.13-1.81）和极好的可重复性（ICC，0.75-0.99）。判别分析允许通过面部和牙弓尺寸以及牙齿大小来识别 4 个人群。牙颌面生物计量学显示女性的准确率为 98%，男性的准确率为 100%，这证实了牙颌面特征具有高度的组内同质性和相当大的组间异质性。
人类面部的生物测量值加上牙齿大小和牙弓尺寸对于准确识别偏远的土著群体非常有用。这些发现支持人类遗传学的先前研究，强化了遗传变异在确定牙颌面特征中的作用。
