Study of dental and skeletal disorders in mono- and dizygotic twins.

UNLABELLED The aim of this study was to analyze and to compare the dental and skeletal morphology of mono- and dizygotic twins (MZ and BZ). MATERIAL AND METHODS 10 sets of monozygotic (mean age: 18.5 years) and 10 sets of dizygotic (mean age: 19.7 years) twins were examined, cast analysis, ortopantomography and lateral cephalometric films were analyzed. RESULTS The upper frontal teeth dimension and shape is the same in 99.69% of MZ and 93.91% of the DZ twins. In MZ twins we found different values for transversal arch width and upper intercanine distance. The dental malpositions were different in the DZ sets, especially in tranversal and sagital plan. The same differences were seen in the arch forms. The skeletal pattern was also different between the components of DZ twins. The cephalometric values showed slight differences of the interincisal angle both in MZ and DZ twins. CONCLUSIONS Genetically influenced patterns can be explained by the results of our study.