The Carabelli trait in the mixed deciduous and permanent dentitions of five South African populations.

The Carabelli trait in South African negroids, caucasoids, Coloured (Peninsula and Namaqualand) and Indians, classified according to Alvesalo, Nuutila and Portin (1975; Acta odont. scand. 33, 191-197) showed generally peak frequency of expression for dm2 falling into class 3 and for M1 into class 4, that dm2 displays more negative expression (class 2 and 3) and M1 more positive expression (class 4 and 5) and that overall expression in dm2 is higher than in M1. The Indian group was an exception with peak frequencies in class 2 for dm2 and class 1 (right) and class 2 (left) for M1. There was no sex dimorphism and there was a tendency for concordance of expression between sides but not within sides.