Introduction. Cone-beam computed tomography (CBCT) is considered to be the most informative radiographic method for pre- and postoperative analysis of the maxillary anatomy and for avoiding further complication. Canalis sinuosus is one of such structures that damage can go along with bleeding and neurological symptomatology. The aim of the study was to investigate radiological and morphometric features of the canalis sinuosus in Russian population using CBCT technique. Materials and Methods. 150 CBCT scans of 61 males and 89 females aged from 24 to 80 years were retrospectively studied with different slice thickness and evaluated with regards to prevalence and diameter among age and gender groups in Russia. Results. CS prevalence in this study was 67%, and CS was most frequently presented in the lateral incisor region (33.5%). Women showed statistically higher CS prevalence (p<0.01) than the male group, and there was no statistically significant difference observed between occurrence and localization of CS and age groups. Conclusion. CBCT examination demonstrated good diagnostic efficiency in CS visualization, and the CS may have variations on its location and prevalence with statistically significant differences between the gender group and without significant differences among age groups and can depend on the population.

Abstract. The molecular level of physiological processes in the context of studying the pathogenesis of diseases is the basis for their diagnosis and treatment. Thus, the features of the pathogenesis of periodontitis are the direct participation of pro-inflammatory cytokines in the development of alterative inflammation. The study of the cytokine profile is relevant for both diagnostic and therapeutic purposes, since the dynamics of indicators of inflammatory mediators reflects the degree of activity and specificity of pathological reactions present in periodontitis. The purpose of the study Study of cytokine profile indicators in experimental periodontitis. Materials and methods. In an experiment on 50 white non-linear rats weighing 190-280 g, the model of experimental periodontitis proposed by Shkolnaya K.D., Atrushkevich V.G. was reproduced. (Patent RU No. 2625295 dated 07/12/2017). Assessment of the dynamics of the cytokine status of blood serum was carried out by the level of pro-inflammatory (IL-1β, TNF, IL-6, IL-17), anti-inflammatory (IL-4, IL-10) and regulatory (IL-2) cytokines using enzyme-linked immunosorbent assay using reagent kit "Bender MedSystems". Results. The study revealed the presence of an imbalance in the cytokine system, characterized by a violation of the physiological balance between pro-inflammatory and anti-inflammatory cytokines with a predominance of the former. Hyperproduction of cytokines persisted throughout the experiment with an increase in the above uncoupling by day 25, which indicates the formation of an immunoinflammatory process in the periodontium. Conclusion. The data obtained during the study confirm the presence of an imbalance of the cytokine network, which indicates the formation and progression of the inflammatory process of the periodontal complex, and also necessitates the introduction of drugs that inhibit the synthesis of pro-inflammatory mediators into complex therapy.

Lipid peroxidation analysis and identification of the main damage predictors lead to introduction of new diagnostic and treatment technologies into medical practice. The aim of the study was to evaluate the activity of free radical damage processes and identify their association with collagen metabolism disorders in the disease dynamics in experimental periodontitis. Materials and Methods. An experimental study was carried out on 60 white non-linear rats. A rat model of periodontitis was reproduced according to K.D. Shkolnaya and V.G. Atrushkevich method (Patent RU No. 2625295, December 07, 2017). The overall activity of free radical oxidation and antioxidant potential was assessed according to biochemiluminescence parameters. Lipid peroxidation activity was assessed according to the parameters of primary and secondary peroxidation products. Collagen metabolism was assessed by P.N. Sharaev method. Results. The rat model of periodontitis demonstrated a high level of free radical oxidation parameters. At the same time decrease in the antioxidant potential was observed throughout the experiment. It proved a significant inhibition of the antioxidant system ability to neutralize bioradical oxidation reactions. The resulting free radicals caused the collagen destruction, which formed the frame of the periodontal connective tissue structures. It was confirmed by hydroxyproline increase due to its free and peptide-bound fractions throughout the experiment. Finally, an increase in protein-bound hydroxyproline was determined against the background of high levels of free hydroxyproline, which was explained by the formation of pathological granulations and fibrillar collagen with an inferior short-chain structure. Conclusion. Chronic periodontitis is characterized by disturbances in the bioradical balance followed by the oxidative stress development, which induces the dystrophy of periodontal collagen structures. The data obtained substantiate the use of collagen peroxidation and metabolism markers as diagnostic criteria to predict the course of periodontitis, and also prove the importance of antioxidants.

Relevance. The features of the dynamics of free radical processes, as well as the metabolism of collagen structures of the connective tissue matrix against the background of periodontitis will reveal deeper pathogenetic mechanisms and application points for the introduction of new therapeutic and diagnostic technologies into practice. The purpose of the study. Assessment and establishment of interrelations between the intensity of bio-radical processes and collagen metabolism in dynamics in experimental periodontitis. Materials and methods. The study used 45 white nonlinear rats, on which the model of periodontitis proposed by Shkolnaya K. D., Atrushkevich V.G. (Patent RU No. 2625295 dated 12.07.2017) was reproduced. The total activity of free radical oxidation and the antioxidant potential of the body were monitored by the biochemiluminescence method, and markers of collagen metabolism were recorded. Results. The study revealed a sharp predominance of oxidative processes and the inability of the antioxidant potential to suppress free radical peroxidation, as evidenced by the persistently high levels of total luminescence intensity and biohemiluminescence light sum that persist throughout the experiment, despite dynamic changes. Reactive oxygen species in conditions of progressive chronic inflammation have a damaging effect on collagen fibers, which means they lead to the inevitable destruction of the periodontal complex, which is expressed in the growth of CO and PSO. In addition, there is a significant direct correlation between the dynamics of the intensity of free radical oxidation and the indicators of collagen metabolism. Conclusion. Thus, oxidative stress, progressing against the background of periodontitis, leads to disorganization of connective tissue structures of the periodontal. In turn, the study confirms the validity of the use of markers of the intensity of free radical oxidation and collagen metabolism to diagnose the severity of the disease and prognosis, as well as the need for the use of antioxidant drugs as part of complex therapy.