Hereditary Factors and Tooth Dimensions: A Twin Study

Introduction: Determination of the actual level of genetic determinance of occlusal variation could have a significant effect on prognosis and treatment planning. Aim: The objective of this study was to evaluate the hereditary variations occurring among the members within monozygotic and dizygotic twin pairs based on widest mesiodistal measurements in relation to the posterior permanent dentition. Materials and methods: Twenty-eight adult twin pairs (16 monozygotic pairs, 12 dizygotic pairs) in the age group of 14 to 55 years were used for the study. Mesiodistal measurements of maxillary and mandibular permanent posterior teeth at their maximum width were considered. Intrapair differences were calculated, the differences in the two groups were compared and the level of significance was tested. Results: Significant differences between the twin groups was found in relation to all the teeth studied except the maxillary and mandibular second molars. Conclusion: Genetically conditioned variations of highly significant nature were seen in 12 of the 16 posterior teeth studied, thereby confirming the evidence that size of teeth is under genetic control.