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Background: Teeth changes after chemotherapy are of clinical importance, but no morphological studies were conducted on microscopic level., Aim: To assess morphological changes in teeth developing under chemotherapy., Materials and Methods: Twenty-nine adolescents aged 13-16 years that received chemotherapy at the age of 2-13 were included in the study. Teeth morphology was evaluated by means of clinical and radiological data as well as microscopy of extracted teeth (n=13). Thirty healthy children aged 13-16 and 8 teeth extracted for orthodontic reasons served as a control., Results: Chemotherapy has arresting impact on teeth development confirmed by aplasia of germs when influenced on stages I-II (p=0.0001), preliminary apexogenesis resulting in shortened roots in teeth at the later stages of growth and development (p=0.01). Enamel and dentine defects usually located in cervical area are also a specific feature, while caries incidence was not higher when compared to control group., Conclusion: Children receiving chemotherapy have high risk of secondary teeth loss because of germs aplasia and extraction of severely decayed teeth. Early diagnostics helps to prevent secondary deformations of dental arches by prompt prosthetic rehabilitation. Root morphology changes should be considered by root canal treatment.

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.

Morphogenetic causes of the origin of true hypsodonty and transformation of bunodont teeth pattern to lophodont one in the rodent evolution are discussed. Wide distribution of these processes in different rodent groups and many other mammals can be explained by the universality of morphogenetic mechanisms of teeth development and by scantiness of their possible transformation pathways.

Effects of an intrauterine streptococcal infection induced at different stages of pregnancy on the developing fetus and newborn were studied in non-inbred white rats. The course of denture development was found changed in both fetuses and newborns. A number of functional shifts in the central nervous system and physical status, presenting in the postnatal period, were detected in the experimental animals.

By means of the computer a multiple regrouping of 1090 caucasians and 1035 Mongoloids at the age of 17-21 years and 98 (corpses) caucasian ++ men at the age of 17-38 years has been performed with a subsequent inter- and ++intra-grouping analysis of 27 variants of the structure of the maxillodental system separately for the lower and upper jaws. A certain regularity between enlargement of the teeth size, increasing angle of the lower jaw and decreasing size of the longitudinal and expressive dimensions of the jaws (in accordance with decreasing size of the spongy substance and its cells) has been revealed. It is accompanied with increasing caries and vice versa within all the groups studied. There are certain borders for individual variants in every group (race, sex, wide-, middle- and ++steno-osseous). The morphotypes of the maxillo-dental system revealed are constitutional. They are marker for ontogenic rates and help to explain peculiarities++ of its individual specific reactions to caries liability.