Comparison of Permanent Mandibular Molar Crown Dimensions between Mongolians and Caucasians

Abstract

The aims of this study were to compare crown dimensions of mandibular first molars (M1) and second molars (M2) between Mongolians (belonging to the Khalkha-Mogol grouping) and Caucasians (Northern European ancestry) and to attempt to explain any observed differences in phylogenetic and ontogenetic terms. Materials in this study comprised dental casts of 48 Mongolian female subjects with a mean age of 20.5 years and 50 Caucasian female subjects with a mean age of 21.5 years. For M1, the buccolingual diameters of both mesial and distal crown components in Mongolians
were significantly larger than in Caucasians. For M2, the mesiodistal and buccolingual diameters of the distal crown components in the Mongolian sample were significantly larger and the mesiodistal and buccolingual diameters of mesial components were significantly smaller compared with those of Caucasians. Common environmental effects, possibly related to the prenatal environment, as well as genetic influences, may be contributing to the differences in buccolingual dimensions of M1 between Mongolians and Caucasians. Given that the M2 develops later and over a longer period of time than the M1, it is reasonable to assume that this tooth may be subject to greater environmental pressures than applied to the M1.