FEATURES OF THE STRUCTURE HARD TISSUES OF THE TOOTH IN A REGION WITH HIGH LEVELS OF FLUORIDE IN DRINKING WATER

Petrushanko V. M., Lobach L. M., Lyashenko L. I., Brailko N. M., Tkachenko I. M.

DENTISTRY

Scentific article

Abstract. The problem of diagnosis and treatment of caries, its complications and non-carious lesions remains relevant in dentistry. The development and use of new methods of treatment of hard tissue lesions requires indepth knowledge of the structure of dental tissues, especially in regions with different content of trace elements in water and food. In the Poltava region, the content of fluoride in drinking water is high, and this leads to fluorosis. The increased concentration of fluoride causes its rapid accumulation in the organs of the oral cavity, and as a consequence – the transformation, and subsequently the imbalance of trace elements in the organs of the oral cavity. The basis of tooth enamel is apatite crystals. 75% hydroxyapatite, 19% carbon apatite, 4.4% chlorine apatite, 0.66% fluorine apatite. When the number of trace elements changes, isomorphic substitution occurs and the composition of ideal hydroxyapatite (Ca10 (PO4) 6 (OH) 2 changes, and this is a very unfavourable factor for the course of caries. The study was performed on 40 teeth removed according to surgical indications in the residents of Poltava (fluoride content in drinking water is 1.5-1.8 mg/liter) with a carious process on the background of physiological abrasion (20 teeth), with increased abrasion and carious process (20 teeth). Enamel and dentin of teeth were examined to solve the set tasks. The main morphological changes are found in the surface layer of enamel where the peripheral area looks like a narrow chalk line. Due to the partial resorption of enamel prisms and the interprism substance, the enamel prisms do not fit tightly together. Rows of prisms on the chip fall at different levels and thus the enamel takes on a characteristic appearance reminiscent of a marble pattern. At high concentrations of fluorine areas of enamel decay are observed. They alternate with areas of amorphous structure, where there are crystals of hydroxyapatite of various sizes, including with a normal structure. At the bottom of erosions find coarse grain. The structure of the main substance of dentin is compacted; near the dentinal tubules the zone of hypercalcification is clearly visible. Assessing the differences in the performance of teeth with high abrasion and the presence of a carious process, we can note a significant difference in the performance of sodium, calcium in the enamel and magnesium in the dentin at (p <0,05). Differences were also found in the area of enamel in the preparation area with a probable difference in magnesium between the two groups, at a distance of 5 μm from the preparation area (in the area of the lubricated layer) differences in the amount of strontium, magnesium and carbon. In the area of dentin examination directly in the preparation area, there are significant differences in the amount of silicon, magnesium and zinc. Such changes affect the destruction of the crystal lattice of hydroxyapatite. Fluoride forms a complex with calcium ions, which is excreted from the body, resulting in a decrease in the amount of calcium salts and impaired mineralization. Therefore, such changes must be taken into account both in preventive measures and in the treatment of hard tissue defects. The connection of adhesive systems at different degrees of mineralization will also be different and this should be taken into account when choosing an adhesive system. Given the significant concentration of fluoride in the Poltava region in the teeth there are areas of enamel decay, with areas of amorphous structure and therefore for better fixation it is necessary to use filled adhesive systems that can better integrate into decay areas and thus firmly fix the filling material. To reduce the toxic effects of fluoride, it is necessary to systematically apply magnesium ions, which can be part of toothpastes and rinses, as well as vitamin complexes. Interacting in the small intestine, magnesium reduces the absorption of fluoride, and hence its toxic effects.

enamel, dentin, hydroxyapatite, fluorine, silicon, magnesium, zinc, calcium, adhesive.

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«Bulletin of problems biology and medicine» Issue 2 (160), 2021 year, 315-319 pages, index UDK 616.314:611.018(477)

10.29254/2077-4214-2021-2-160-315-319