X-RAY SPECTRAL ANALYSIS OF DENTAL HARD TISSUE TRACE ELEMENTS (ELECTRON-MICROSCOPIC EXAMINATION).

The role of trace elements (microelements) in maintaining oral health has not been fully investigated and still remains the subject of research and discussion. Some trace elements contribute to the development of caries, while others, on the contrary, prevent formation of this process and accelerate the restoration of dental hard tissues. Penetration of trace elements into human dental structures via saliva, food, water and other routes contributes to the formation of carious diseases, or, conversely, its cessation and/or regression. Analyzing the studies allowed us to conclude that there is very scarce information available in the literature about the layered, zonal distribution of "vital" trace elements in healthy (intact) teeth dentin and enamel. However, to study the distribution of caries-static elements (Ca, F, P) on the enamel surface as well as in para-pulpal dentin is of great importance as well. It was aimed to identify trace elements in human teeth structures (enamel, dentin and cementum), as well as to determine their localization and concentration. To reach this objective, X-ray spectral analysis on 6 intact, extracted teeth has been performed by Scanning Electron Microscopy (SEM). Identification of trace elements was performed on the 6 sites/locations of these teeth: enamel surface layer, enamel thickness, enamel-dentin border, parapulpal dentin, root dentin, and cementum. As a result, it has been found that the distribution of essential trace elements in dental hard tissues is uneven, while such an important element in maintaining healthy teeth as Fluorine has been found in only minimal concentrations in hard tissues.

THE INFLUENCE OF CHRONIC HYPERHOMOCYSTEINEMIA ON PHAGOCYTIC AND METABOLIC ACTIVITY OF PERIPHERAL BLOOD NEUTROPHILS IN CASE OF LIPOPOLYSACCHARIDE-INDUCED PERIODONTITIS.

The aim of the study was to investigate the phagocytic and metabolic activity of peripheral blood neutrophils in rats with lipopolysaccharide (LPS)-induced periodontitis combined with chronic thiolactone hyperhomocysteinemia (HHcy).The experiment included non-linear mature male rats (n=48), which were divided into 4 groups: control; animals with a periodontitis model; animals with a model of chronic thiolactone HHcy; animals with a model of periodontitis in combination with chronic thiolactone HHcy. Phagocytic activity, phagocytic index and phagocytic number were determined as indicators of phagocytosis of peripheral blood neutrophils. The oxygen-dependent bactericidal activity of peripheral blood neutrophils was studied using nitroblue tetrazolium test (NBT-test).Our research has found that LPS-induced periodontitis in rats is accompanied by dysfunction of phagocytosis process (increased phagocytic activity with a simultaneous decrease of absorption capacity) and activation of oxygen-dependent microbicidal mechanisms of peripheral blood neutrophils, as indicated by an increase of indices of spontaneous and activated NBT-test. Chronic thiolactone HHcy adversely affects the functional and metabolic activity of peripheral blood neutrophils in case of periodontitis, which is confirmed by a violation of the process of phagocytosis, a more pronounced decrease in absorption capacity and depletion of metabolic reserves of these cells in rats with comorbid course of LPS-induced periodontitis vs. animals with only LPS-induced periodontitis. The observed disorders in the process of phagocytosis in rats with comorbid course of periodontitis are an important factor in reducing the non-specific organism resistance which contributes to the progression of periodontitis. The obtained results reveal new aspects of the high Hcys plasma level influence on the course of inflammatory process in periodontal tissues, which opens opportunities for improving pathogenetic therapy in patients with periodontal disease combined with chronic HHcy.

CORRELATION BETWEEN CONNECTIVE TISSUE METABOLISM AND THYROID DYSFUNCTION IN RATS WITH PERIODONTITIS.

The aim of the study was to clarify mechanisms of the periodontitis development in rats with thyroid dysfunction based on a comparative analysis of the correlations between the connective tissue metabolism indices and the concentration of thyroid stimulating hormone, free thyroxine and free triiodothyronine in blood serum. 12-14-week-old inbred white male rats (n=48) were included to the experiment. They were randomly divided into the following groups: control; animals with a model of periodontitis; animals with periodontitis in a setting of hyperthyroidism; animals with periodontitis in a setting of hypothyroidism. Concentrations of free thyroxine, free triiodothyronine and thyroid stimulating hormone were assayed with ELISA method. Collagenolytic activity, content of glycosaminoglycans, free hydroxyproline, fucose, unbound with proteins were determined by the spectrophotometric method. The linkages between the studied indices were established on the basis of the results of the correlation analysis using the Pearson correlation coefficient. Our research has found different interconnections between the indices of connective tissue metabolism and free triiodothyronine, free thyroxine and thyroid stimulating hormone concentrations in case of experimental periodontitis combined with thyroid dysfunction, indicating that thyroid gland has regulatory influence on connective tissue metabolism. In hypothyroid rats more correlations have been established compared to the hyperthyroid rats.