Sex Determination from Teeth Size in Thais

Sex determination is a vital step in reconstructing an individual profile from unidentified skeletal remains. Among various skeletal parts, pelvis and skull are traditional sex indicators, but teeth can often be useful when such favor segments are not available. Many studies on sex determination by population’s teeth had been studied and each finding indicated different level of sexual dimorphism. This study aimed to determine the degree of Thais’ sexual dimorphism using univariate statistical methods and develop function applied from discriminant analysis. Mesiodistal (MD) and buccolingual (BL) dimensions of all teeth except the third molars were measured from dental models of 177 individuals (67 males and 110 females), kindly supplied by the Faculty of Dentistry, Mahidol University. The result showed that males’ teeth were statistically significant (p < 0.05) larger than females’ in 45 out of 56 variables by both MD and BL dimensions, mostly from BL. The BL dimension of upper second molars was the most dimorphic variable, followed by the canines. The latter showed the greatest level of sexual dimorphism in many studies. As for stepwise discriminant analysis, groups of function were designed based on possible scenarios which dental remains were found. Besides, for all teeth, BL dimension of lower right canine (C) was the best discriminatory variable followed by lower left second molar (M2) in MD measurement. This function gave 70% accuracy in sexual dimorphism indicated that it is population-specific. Multivariate analysis (Discriminant function) expressed different results from univariate analysis. This re-confirmed the earlier findings that considering teeth as a unit (multivariate) was more reliable than focusing each particular tooth (univariate) since they are correlated with each other. This is the first study on sex determination from teeth size in Thai population.