Introduction: Over the last decades, the problem of formation and circulation of micro-organisms with resistance to antimicrobials has been steadily increasing. Hospital-acquired infections (HAI) are one of the most pressing problems in medicine, urgency of which is associated with high rates of morbidity, mortality, and significant socio-economic losses. Objectives: The aim of the study was to investigate antimicrobial activity of commercial disinfectants on typical and clinical isolates of bacteria of genus Staphylococcus.

Chronic inflammatory-dystrophic lesions of periodontal tissues are widespread in Ukraine and the world diseases with complex etiology and pathogenesis. The purpose of the study: to establish the biochemical and cultural properties of microorganisms in periodontal pockets in patients with acute generalized periodontitis using a bacteriological method. Materials and methods: the contents of the periodontal pocket were taken from 10 patients with subsequent seeding on nutrient and differential diagnostic media in the bacteriological laboratory. Cultural, as well as the biochemical, and enzymatic properties of bacterial isolates were identified. Results: Pathogenic and opportunistic microorganisms (aerobes and facultative anaerobes), which had a wide range of biochemical properties (additional factors of colonization and pathogenic action) were identified. Purulent microflora was detected in 70.00% of cases. Isolates of Streptococcus, Staphylococcus and P. aeruginosa were predominantly β-hemolytic (except for E. faecalis and S. pneumoniae). The identified bacteria of the intestinal group and the Klebsiella family were lactose- and glucose-positive, K. oxytoca was the most enzymatically active microorganism. Conditionally pathogenic microorganisms of periodontal tissues and oral cavity, as well as the human body as a whole, belong to the facultative microbiota. It is shown that the level of inflammatory process varies with the number of associates of opportunistic pathogens isolated from the inflammatory process. In titers of 102–104 CFU / ml, representatives of the facultative microbiota, as a rule, do not show their pathogenic qualities. At the same time, biochemical properties are essential in the potential ability of opportunistic pathogens to acquire signs of pathogenicity. The titer of bacteria, their hemolytic and proteolytic properties significantly affect the level of virulence of microorganisms. The ability to hemolysis of erythrocytes, found in most isolates, allows to attribute the isolated strains to potentially pathogenic. It is established that the persistence of opportunistic pathogens with a high level of virulence determines the course and intensity of the inflammatory process of periodontal tissues. Conclusions: The study of the role of pathogenic and opportunistic microorganisms in the development and maintenance of long-term inflammation of periodontal tissues is a topical issue in medical science and is necessary for the verification of treatment regimens and compliance with infection control

Annotation. The lack of unified approach or algorithm for expert assessment of the endodontic treatment quality is the reason for registration of various prevalence indicators considering unsuccessful outcomes of pulpitis and periodontitis treatment, misinterpretation of the results and occurrence of problematic situations during the process of forensic dental assessment of iatrogenic dental status changes. Objective – to systematize and analyze the existing problematic aspects of expert assessment of the endodontic treatment quality and identify the most reasoned approaches for objectification of the endodontic interventions consequences. During provided research the calculation methodologies of indexes designed for assessing the consequences and results of endodontic treatment were studied. Additionally, a retrospective analysis of publications with described cases of complex and commission forensic medical and forensic dental examinations of dental care defects was provided, including endodontic treatment cases, cases with errors during endodontic interventions, and also relevant expert conclusions. Revealed that following index indicators could be used as the most expedient approaches for the objectification of endodontic interventions consequences: Peri-Apical Index (PAI), CBCT-PAI, Complex Periapical Index (COPI), Endodontically Treated Tooth Index (ETTI) and PESS (Periapical and Endodontic Status Scale); however, such indexes do not fully assess the quality of iatrogenic manipulations in the structure of the endodont. Thus, for a comprehensive assessment of the derived parameters associated with the dental treatment quality, and quality of endodontic interventions in particular, it is advisable to include in the forensic dental evaluation protocol the main domains, such as technical characteristics, level of patient satisfaction, level of service provided, additional components of the treatment process, and also additional ones, such as verification of experience, quantification of quality of life associated with changes in dental status, and stratification of the effectiveness of treatment.

Resume. The prognosis of dental implantаtion success for patients with a history of generalized periodontitis differs from the prognosis for dental implantation in patients with healthy periodontal tissues. The aim of this study was to evaluate the correlations and effects of vitamin D as a possible predictor of dental implantation failure in patients with chronic periodontal disease. Twenty-seven people who underwent dental implantation were selected for this study. Patients were divided into the following groups: control group (patients with GP without peri-implant; n = 22), group 1 (patients with GP and signs of periimplantitis; n = 5); Clinical evaluation of the mucosa around the implants and implant motility was performed. We assessed the presence of bone loss around the implants by X-ray. According to our research, the content of vitamin D in the blood was statistically significantly correlated with the success of osseointegration in patients with GP. Patients with GP and vitamin D deficiency showed higher bleeding by probing (p = 0.002) and bone loss around the implant (p = 0.004) compared with patients without vitamin D deficiency. Key words: dentition defects, chronic periodontitis; dental implantation; periimplantitis.