The Metric Features of Teeth in Female-to-Male Transsexuals

The aim of the study was to evaluate the odontometric characteristics of female-to-male transsexuals (FtM) in comparison to control groups of males and females. A total of 48 FtM, aged 20–28 years, were studied. For each tooth, two standard measurements were taken: the mesiodistal (MD) and the buccolingual (BL) diameter of the crown. Significant differences between males and females were found in BL measures of all maxillary teeth as well as mandibular lateral incisor and canine. Within the MD measures, the most distinguishing were maxillary and mandibular canines and the first molars. For seven teeth, there were a total of 14 comparisons of MD (half for the maxilla and half for the mandible) between the control men and women. Of these, the men had larger diameters for 12, of which four were statistically significant. There were also a total of 14 comparisons of BL diameter; of these, the men had larger diameters for 13, of which nine were statistically significant. For seven teeth, there were a total of 14 comparisons of MD between the control men and the FtM. Of these, the men had larger diameters for 12, of which seven were statistically significant. There were also 14 comparisons of BL; of these, the men had larger diameters for 10, of which six were statistically significant. For seven teeth, there were a total of 14 comparisons of MD between the control women and the FtM. Of these, the women had larger diameters for nine, of which three were statistically significant. There were also a total of 14 comparisons of BL; of these, the FtM had larger diameters for 13, of which five were statistically significant. Our study revealed that the shift of values of metric features in teeth of FtM towards males was more frequent in the more sexually dimorphic BL diameters characterized by significantly greater width of the crown of five teeth: maxillary canine, first and second molars, as well as mandibular incisors. The results showed intermediate status of female-to-male transsexuals’ teeth between the males and females, which may suggest a genetic basis of transsexualism.