Odontometric variations of permanent crown in Punjabi and U.S. twins.

The study reports odontometric variations within and between Punjabi and U.S. twins. The data are based on 23 MZ and 35 DZ Punjabi twin pairs and 32 MZ and 43 DZ U.S. pairs. None of the t' tests indicates differences between MZ and DZ mean dental dimensions in either sample. Mean tooth dimensions of Punjabi twins are in general greater than those of U.S. twins with significant differences for about 25% of the traits. Coefficient of variation is highest in lateral incisors and canines and lowest in first molars in both samples. The two samples differ more in their variances than in their means. The results indicate that buccolingual dimensions of mandibular traits are under relatively greater selection pressure.