Evaluation of Dento-craniofacial Characteristics in Monozygotic Twins - Case Study

Introduction: Monozygotic twins are a valuable sample for the study of human craniofacial growth and development. Aims: The aim of the present study was to analyze the dento-craniofacial characteristics in monozygotic twins and to discuss the genetic, epigenetic and environmental influences in the twin’s phenotypic features. Material and Methods: Two 21-year-old female twins attended the Dental Service of Universidade Federal dos Vales do Jequitinhonha e Mucuri were analyzed. For validation of this study, a genetic test of zygosity was performed to confirm the individuals' monozygosity. Intraoral buccal examination revealed occlusal differences as well as disagreement in the eruption of the third molars. Results: The analysis of models showed differences in the mesio-distal diameter of the teeth of both arches, as well as disagreement in the perimeter of the mandibular arches between the two individuals. The cephalometric analysis showed remarkable differences in the vertical and horizontal parameters of the craniofacial structure. The SNA, SNB and LAFH showed differences of 10º, 9º and 3mm respectively. Additionally, the components related to the dentition also showed discrepant results. Conclusion: It can be suggested that the dento-craniofacial characteristics present a genetic component; however, the interaction of epigenetic and environmental factors can lead to different phenotypes in univiteline twins.