The paper deals with studying the morphological changes in the tooth germs and surrounding tissues in newborn rats born with experimentally induced macrosomia. The purpose of the study was to detect morphological features of the oral mucous membrane (mucobuccal fold and cheeks); especially the tooth germs, and surrounding tissues in experimentally induced fetal macrosomia in newborn rats. Material and methods. The Wistar Albino Glaxo rats aged 1 day were used in all experiments. Four different experimental models were used for macrosomia formation. The somatometric examination of the rats (weighing, measurement of body length, and tail length) was conducted immediately before withdrawing animals from the experiment. The animals were divided in five groups (6-7 animals in each group) according to their body weight, body length, the Quetelet index at birth and model of macrosomia formation. Results and discussion. We revealed abnormalities in the morphogenesis of the tooth germs and adjacent tissues in all macrosomic rats. However, different weight-height ratios for newborn rats and different ways of macrosomia formation result in some originality of these abnormalities. Macrosomic rats born with large body length and relatively reduced body weight, had a dense network of microcirculatory bed of the oral mucosa (mucobuccal fold). These rats had a thicker layer of enamel being formed, which, however, had the signs of hypoplasia and aplasia. We also detected the thick dentin layer and the signs of odontoblast destruction. In macrosomic rats with well-balanced pre-natal development, the condition of the tooth germs and surrounding tissues was close to that in the control group. But we found a significant decrease in the number of odontoblasts in the peripheral layer of the pulp in the dental papilla. We observed a modified microcirculatory bed of the oral mucosa, thinner than in the control group layers of enamel and dentin, and signs of immaturity of odontoblasts in macrosomic rats born with signs of intrauterine obesity. Conclusion. High weight at birth can be an integral indicator of the presence of various disorders in the morphogenesis of the tooth germ and tissues that surround the tooth germ. The dominance of pre-natal obesity or pre-natal accelerated body growth, or the well-balanced acceleration of body weight and height gain, has its own characteristics in the microscopic picture of tooth development in the newborn period.
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