The thesis is devoted to studying of morphological, immunohistochemical, molecular-genetic and chemical peculiarities of parodontium tissues at inflammation and various kinds of epulis. Parodontium tissues of 94 deceased persons with various somatic pathology were studied, archive of histological blocks from 53 patients, who were histologically diagnosed with epulis, was analyzed; infrared spectrophotometry, Western-blot analysis, comet phoresis, immunohistochemical research, light microscopy, electronic microscopy with chemical analysis, mathematic and statistic data processing were applied. The thesis presents new theoretic substantiation and solution of urgent problem of morphogenesis of various kinds of epulis and shows their inflammatory origin. It is shown that accumulation of chrome and cobalt ions in parodontium leads to development of giant-cell epulis. It is established that during inflammation of DNA, parodontium tissues are methylated. The way of DNA methylation at chronic inflammatory process is established, which is connected with reducing of reparative MGMT enzyme. It is shown that accumulation of chrome and cobalt ions takes place in giant cells of giant-cell epulis, which have macrophagal origin and leads to changes of alveolar bone. The level and disctinctiveness of morhological changes in parodontium tissues depend on bacteria, term of inflammatory process course, influence of cobalt and chrome ions and level of DNA fragmentation. Ig G and IgM promote englobing of microbial cells at parodontium inflammation and form one of the main link in pathogenesis of various kinds of epulis and indirectly stimulate accumulation of different elements in giant cells Cu up to 2.61 ± 1.3 % (P > 0.05), Fe up to 6.69 ± 0.05% (P < 0.01), Co up to 11.7 ± 0.14 % (P < 0.05). During studying of parodontium state in different age groups, it is shown that changes of biocenosis of oral cavity are developed already in childhood. Giant-cell epulis (osteoclastoma) is quite frequent neoplasms of dentofacial system, which also can take place in skeleton bones. Our researches established that diagnosis giant-cell epulis can be verified on the ground of the following immunophenotype of giant cells: positive reaction (+) with markers CD 68, OPN, S100 and negative status (-) of markers Кі-67, CD3. Absence of reactions or positive expression of markers S100, ММР1 and VEGF is the ground for establishing of bone resorptive potential of giant-cell epulis. ММР1 - status is decisive for verification of this potential. VEGF reflects vascularization of giant-cell epulis. In case of negative status of ММР1, VEGF, S100 and absence of coloration, significant resorption potential of alveolar bone is excluded. Diagnostic value of this method consists in possibility of exact verification of diagnosis of giant-cell epulis, making complex evaluation of morphological and immunohistochemical criteria, excluding the most similar researched neoplasms by morphological criteria: giant-cell granuloma, cherubism etc., which is confirmed by own histogenesis of giant-cell epulis. Therefore, offered method of diagnostics of giant-cell epulis is based upon molecular-biological properties of giant cells, enabling to increase the accuracy of diagnostics, as well as information value of final result at pre- and post-surgical stages, that can not only improve the prognosis, but also save the patient's life quality.
