Clinical observation of 15-year-old children who lived and studied in conditions of iodine deficiency was carried out. In order to assess the cariogenic situation in the oral cavity of children, the hygienic index (OHI-S), caries index (KPV), mineralizing potential of saliva (MPS), tooth enamel resistance (TER-test according to V.R. Okushko) were studied; the quantitative composition of total calcium and inorganic phosphorus, acid phosphatase activity, pH, as well as viscosity, saliva secretion rate were determined in the oral fluid. The peculiarities of the food diet and behavioral factors were analyzed according to the data of the children's questionnaire. Changes in the biochemical and biophysical characteristics of oral fluid depending on the dental status of 15-year-old children who lived in areas with insufficient iodine content in environmental objects were studied. In children with caries-affected teeth, compared to children with intact teeth, we noted a decrease in the level of total calcium (from 1.23±0.01 mmol/l to 1.06±0.01 mmol/l, p˂0.05) and calcium - phosphorus coefficient (from 0.33±0.005 to 0.28±0.005, p˂0.05), increase in the content of phosphate ions (from 3.75±0.03 mmol/l to 3.87±0.04 mmol /l, p˂0.05) and acid phosphatase enzymatic activity (from 50.71±2.70 U/l to 67.22±1.13 U/l, p˂0.05), decrease in the rate of salivation ( from 0.54±0.01 ml/min to 0.41±0.01 ml/min, p˂0.05), a shift in the level of hydrogen ions to the acidic side (from 7.21±0.07 units to 6 .76±0.06 units, p˂0.05) and an increase in the viscosity of oral fluid (from 1.88±0.03 relative units to 2.48±0.03 relative units, p˂ 0.05). Violations of calcium homeostasis in the oral cavity, acid-alkaline balance and rheological properties of the oral fluid caused a decrease in the mineralizing potential of the oral fluid (from 3.47±0.22 points to 2.42±0.07 points, p˂0.05), which indicated a violation of its mineralizing properties. The mineralizing ability of the oral fluid affected the acid resistance of the enamel, which was evidenced by the increase in the TER-test index (from 1.42±0.14 points to 4.49±0.15 points, p˂0.05). A decrease in the resistance of tooth enamel in children led to the demineralization of hard tissues with the emergence and further progression of the carious process. Such violations of the qualitative and quantitative properties of oral fluid, which increased with increasing anxiety level, caused a decrease in the indicator of the mineralizing potential of saliva in children with a high level of anxiety by 1.5 times more compared to children with a low level (1.89±0.08 points vs. 2.87±0.09 points, p˂0.05). Since the remineralizing properties of the oral fluid determine the degree of mineralization and the structural completeness of the hard tissues of the tooth, a decrease in the mineralizing potential of saliva led to a 2.3-fold increase in the TER test score in children with a high level of anxiety (from 2.77±0.18 points to 6. 28±0.12 points, p˂0.05). A decrease in the resistance of enamel to the damaging action of acids contributed to the initiation of the demineralization process and caused carious damage to the teeth, which was confirmed by a significantly higher KPV index of teeth in children with a high level of anxiety (8.18±0.16 permanent teeth) compared to children with a low level (2, 85±0.17 permanent teeth) (р˂0.05). Children with high levels of anxiety preferred sweets and chips/crackers over fruit and dairy products. High frequency of sugary snacks, regular consumption of sweets and sugary drinks, and preference for taste over nutritional value of foods were higher among children with high levels of anxiety. The pathogenetic mechanisms of the occurrence of caries in children as a result of the interaction of such generally recognized cariogenic factors as the microbial factor, the carbohydrate factor, the resistance of tooth enamel against the background of the violation of the physicochemical properties of oral fluid, which depended on the level of anxiety of children and their adherence to the principles of a healthy lifestyle, were investigated. Key words: dental morbidity, adverse environmental factors, dental caries, prevalence, intensity, children, psychoemotional state, iodine deficiency, mineralizing potential, enamel resistance, oral fluid, prevention, treatment. Branch-Medicine.
