Acharya Ashith B, Mainali Sneedha
Department of Forensic Odontology, S.D.M. College of Dental Sciences & Hospital, Sattur, Dharwad 580009, India.
Forensic Sci Int. 2007 Nov 15;173(1):47-56. doi: 10.1016/j.forsciint.2007.01.024. Epub 2007 Feb 21.
Sex dimorphism in the Nepalese dentition is described using univariate and discriminant analyses. Canines showed the greatest univariate sex dimorphism, followed by the buccolingual (BL) dimension of maxillary first and second molars. Overall, the maxillary teeth and BL dimensions showed greater univariate sex differences. However, less than half of the measured variables (46.4%) showed statistically significant differences between the sexes and the magnitude of sex dimorphism was reduced when compared to other populations. Moreover, reverse dimorphism--where females showed larger teeth than males--was observed in the mesiodistal dimension of mandibular second premolars. This reflects reduction in sexual dimorphism observed through human evolution and the consequent overlap of tooth dimensions in modern males and females. A specific purpose of the study was to develop discriminant functions to facilitate sex classification. A group of functions were developed considering the possibility of missing teeth and/or jaws in forensic scenarios. The functions permitted moderate to high classification accuracy in sexing (67.9% using maxillary posterior teeth; 92.5% using teeth from both jaws). The superior expression of sex dimorphism by means of discriminant functions is in contrast to the univariate results. This is due to discriminant analysis utilising the inter-relationship between all teeth within a dentition--these tooth correlations are not utilised in univariate analysis which results in a loss of information. It is inferred that large-scale statistically significant univariate differences are not a prerequisite for sex assessment.
利用单变量分析和判别分析描述了尼泊尔人牙齿的性别二态性。犬齿表现出最大的单变量性别二态性，其次是上颌第一和第二磨牙的颊舌径（BL）。总体而言，上颌牙齿和BL径表现出更大的单变量性别差异。然而，不到一半的测量变量（46.4%）在性别之间表现出统计学上的显著差异，并且与其他人群相比，性别二态性的程度有所降低。此外，在下颌第二前磨牙的近远中径中观察到了反向二态性——女性牙齿比男性大。这反映了在人类进化过程中观察到的性别二态性的减少以及现代男性和女性牙齿尺寸的重叠。该研究的一个特定目的是开发判别函数以促进性别分类。考虑到法医场景中牙齿和/或颌骨缺失的可能性，开发了一组函数。这些函数在性别鉴定中允许中等至高的分类准确率（使用上颌后牙为67.9%；使用上下颌牙齿为92.5%）。通过判别函数表现出的性别二态性优势与单变量结果形成对比。这是因为判别分析利用了牙列中所有牙齿之间的相互关系——这些牙齿相关性在单变量分析中未被利用，从而导致信息丢失。据推断，大规模具有统计学意义的单变量差异不是性别评估的先决条件。
