[Analysis of the interaction of genotypic and paratypic factors in the development of maxillo-dental anomalies in ontogeny]. / Analiz vzaimodeistviia geno- i paratipicheskikh faktorov v formirovanii zubocheliustnykh anomalii v ontogeneticheskom aspekte.

Component analysis of total phenotypic variance was used to analyze data on 80 pairs of twins aged 3 to 18 years, examined in the Stupino outpatient dental clinic, Moscow oblast. Genotypic and environmental factors are shown to play different roles in the development of abnormalities of teeth, dental arches, and occlusion at different ontogenetic periods of deciduous, mixed, and permanent dentition. Periods when paratypic factors prevailed were revealed. This made it possible to identity periods when prophylaxis and orthodontic treatment are the most advisable.

[The relative role of hereditary and environmental factors in the formation of the maxillodental system]. / Sootnositel'naia rol' nasledstvennykh i sredovykh faktorov v formirovanii zubocheliustnoi sistemy.

The contribution of hereditary and environmental factors to the formation of maxillodental abnormalities in the ontogenetic aspect was analyzed using a twin model. A total of 80 twin pairs aged 3 to 18 were examined. The results permitted the authors define the age periods favorable for therapeutic and prophylactic measures in children with abnormalities of the teeth, dentition, and occlusion. Effects of sex dimorphism on the parameters of the maxillodental system at various stages of ontogenesis were studied. Sex-specific differences were found to augment with age; all the analyzed parameters in boys were superior to those in girls at the age when sex-specific factors completely exerted their effects on the maxillodental system at the period of permanent teeth occlusion.