Object. Causes of failure of endodontic treatment and causes of tooth extraction with a diagnosis of chronic apical periodontitis. Purpose ― to analyze the causes of failure of endodontic treatment and the causes of tooth extraction with a diagnosis of chronic apical periodontitis to determine ways to improve the effectiveness of conservative treatment. Methodology. A retrospective analysis of 864 medical records of a dental patient and 532 results of x-ray examinations of patients who underwent tooth extraction was carried out. 198 dentists-therapists of the city of Tyumen and the South of the Tyumen region were interviewed to determine the shortcomings of endodontic treatment. During the survey, doctors expressed their subjective opinion about the main reasons for the failure of therapeutic treatment of teeth with apical periodontitis and the reasons for their subsequent tooth extraction. Results. According to the survey, the failure of conservative treatment is most often associated with non-compliance with treatment protocols and the complexity of the anatomical structure of the root canals, as well as the inability to adequately clean the root canal system. A retrospective analysis of the data related to tooth extraction revealed that the main cause of tooth extraction is chronic apical periodontitis, which accounts for 69 %. The main reason for the removal of teeth diagnosed with chronic apical periodontitis was a significant destruction of the crown. Summary. In the course of this work, we justified the need to improve existing methods of conservative treatment of apical periodontitis. Improvement of endodontic treatment should be aimed at the development and implementation of effective methods of root canal cleaning and irrigation solution activation. In order to improve the prognosis of endodontic treatment and reduce the proportion of tooth extractions for periodontitis, it is necessary to improve the quality of the final restoration and to monitor its tightness.

Subject: Inflammatory periodontal diseases are one of the most common dental diseases in the world. To ensure successful treatment and a stable period of remission, it is necessary to take into account the etiopathogenesis of the disease. One of the main roles in the development of inflammatory periodontal diseases is played by the immune response of the body to the action of periodontal-pathogenic micro-organisms. Objective ― to study the current literature indicates about the role of immunological processes in the development of inflammatory periodontal diseases, as well as the possibility of their correction Material and methodologies: Data from the scientific literature on the etiopathogenesis of inflammatory periodontal diseases was used in the study. To achieve this objective the databases of the Tyumen State Medical University Library, electronic libraries (eLibrary, Cyberleninka, PubMed, Googl.Scholar), official sites of scientific publications were used. Results: the review of the literature presents information on the immunological processes developing in inflammatory periodontal diseases. The role of cellular and humoral elements in pathogenesis, the role of pro and anti-inflammatory cytokines in the chronization of the inflammatory process is described. The possibilities of local immunological correction in the treatment of inflammatory periodontal diseases are considered. Conclusions: The concept of cytokine development of inflammatory periodontal diseases has been formed and substantiated in modern scientific literature. The evaluation of the cytokine profile of the oral and gingival fluid allows to establish the activity and severity of the disease. The established immunological and molecular genetic mechanisms of the development of inflammatory periodontal diseases associated with the influence of cytokines make it possible to adjust the complex treatment of inflammatory periodontal diseases, determine the direction of personalized therapy of patient, determine the effectiveness of the treatment and the prognosis of the disease.

The lack of information on the relationship between the indicators of micro, macronutrient and dental status of adolescents living in Yamal was the basis for analyzing these indicators. A comprehensive dental examination of 112 adolescents aged 12 and 15 years, from among the indigenous peoples living in the territory of the Yamalo-Nenets Autonomous District, an assessment of the actual nutrition and elemental composition of blood serum was carried out. The analysis of the data showed that the prevalence of dental caries among the examined exceeds 99 %. The CPI index ranged from 4,6-7,7. The imbalance of micro- and macroelements involved in ontogenesis and providing the processes of remineralization of hard tooth tissues was revealed. Correction of the elemental status should be included in the complex of therapeutic and preventive measures that increase caries resistance.