Prevalence of Torus Palatinus and association with dental arch shape in a multi-ethnic cohort.

Torus Palatinus (TP) is a bony projection located on the oral surface of the hard palate. The trait is typically benign, has an unknown etiology, and varies widely in phenotypic expression. Prior studies suggest differences in TP prevalence by sex and ancestry, but the reported rates vary, even within a single ancestral group. We assessed the prevalence of TP and its association with palatal shape in a large multi-ethnic cohort of normal individuals. 1102 adults were included (625 with European ancestry, 377 with West African anscestry, and 100 with East Asian ancestry). 3D digital dental casts were obtained and rated. TP frequencies were compared between sexes and/or ethnicities using Chi-squared tests. Dental cast models were then landmarked, and canonical variates analysis was performed to test for shape differences between those with and without TP. Females had a significantly higher rate of TP than males across all three ancestral groups (p≤0.004). In males, no significant differences were found among ethnicities. Ancestral differences in TP frequency were driven by females, with East Asians having the highest rate (34.69%), followed by Europeans (24.88%) and West Africans (15.22%). Shape differences were found only in Asians and Africans, indicated a shorter and wider palate in presence of TP. Ethnic differences in TP frequency were present only in females. Further, females have considerably higher rates of TP than males in each population tested. Further studies of TP at earlier time-points and in connection to other aspects of craniofacial growth may shed light on these sex and ethnic differences.