基于三维重建技术的上颌牙弓性别判定

Sex Determination of Maxillary Arch Based on the Three-dimensional Reconstructed Models

通过测量骨骼进行性别判定是法医人类学的重要内容,而某个时期一个种群的骨骼数据库往往并不适用于另一时期或另一种群。牙齿和颌骨较其他骨骼有较高的稳定性,往往能保存得更完整。而随着医学影像技术的不断提高,利用计算机对骨骼的三维图像进行测量和分析也成为法医人类学研究的趋势。本研究旨在针对中国中部地区个体,建立利用上颌牙弓多个测量指标判定性别的数学模型并对其判定效果进行评价。首先,测量了180例(男性83例,女性97例)来自中国中部地区个体的上颌牙弓锥形束CT样本上的21项指标;然后,使用统计软件SPSS 24.0筛选出具有性别差异的指标;最后,对具有性别差异的指标的测量数据进行单变量及多变量判别分析,得出性别判定数学模型,并计算其用于性别判定的准确性。结果显示,21项指标中,有10项指标在男性和女性之间存在统计学差异(P<0.05),且男性的上颌牙弓变量均值均高于女性均值;对这10项指标进行单变量判别分析,建立10个判别公式,经过交叉验证得出准确率为57.2%~72.2%,其中,上齿槽弓宽变量的准确度最高,达72.2%;进行多变量判别分析,直接法所得判别公式经交叉验证准确率为73.4%,逐步法经筛选变量后,将上齿槽弓长、上齿槽弓宽两个变量纳入判别分析,交叉验证准确率为72.2%,直接法准确率高于逐步法。本研究表明,所选的上颌牙弓测量指标具有一定的性别判定价值。下一步的研究将探索更多的颅骨骨性标志在法医人类学多方面的应用价值。

Sex determination by measuring bones is an important part of forensic anthropology,and a database of bones from one population at one time is often not applicable to another.Teeth and jaws are more stable than other bones and tend to be preserved more intact.With the continuous improvement of medical imaging technology,the use of computer to measure and analyze three-dimensional skeletal images has become a trend of forensic anthropology research.Therefore,for individuals in central China,this study aims to establish a mathematical model for sex determination by using multiple measurement indexes of maxillary arch and evaluate its effect.Firstly,21 indexes of 180 cases(83 males and 97 females)from central China were measured based on the cone beam CT samples of the maxillary arch.Then,the statistical software SPSS 20.0 was used to screen out indexes with gender differences.Finally,we analyzed the measured indexes with gender differences by single variable and multivariable discriminate analysis,and the mathematical model was obtained and the accuracy of the sex determination was calculated.The results showed that there were 10 indexes with statistical difference between male and female(P<0.05)among the 21 indexes,and the average value of male was greater than that of female.Univariate discriminant analysis was carried out on these 10 indexes,10 discriminant formulas were established,and the accuracy rate was 57.2%-72.2%after cross-verification.Through cross validation,the accuracy of the upper dental arch width was the highest,up to 72.2%.The multivariable discriminant analysis showed that the accuracy rate of the discriminant formula obtained by direct method was 73.4%after cross-verification,and the accuracy rate of cross verification was 72.2%after the variables were selected by stepwise method,and the two variables of upper alveolar arch length and upper alveolar arch width were included in the discriminant analysis.The accuracy of direct method was higher than that of stepwise method.The study showed that the upper jaw arch measurement indexes in this study have a certain value for sex determination.In the next research,we will also explore the application value of more skull bone markers in various aspects of forensic anthropology.