BACKGROUND: At present, the detection of periodontal pathology is not very difficult, especially in unfolding disease stages. Moreover, determining the clinical course and differentiating the diagnosis of nosological forms, prognosis of disease development, its interrelation with the general condition of the patient and the bone system as a whole are more complicated tasks that require further close study. The bone is an active metabolic system that is constantly self-renewed by the processes of resorption and formation. This study focused on the peculiarities of the course of generalized periodontitis (GP) in 104 patients with differentiated and undifferentiated connective tissue dysplasia (UCTD).
 AIM: To diagnose and study the clinical course of chronic GP (CGP) in patients with CTD.
 MATERIAL AND METHODS: This study analyzed retrospective and prospective data obtained in 20162020 as a result of monitoring patients with different severities of CTD: differentiated CTD (DCTD) + CGP (group 1, n=56), undifferentiated (UCTD) + CGP (group 2, n=48), and control group (CG, n=34) with CGP but without signs of musculoskeletal dysplasia. The study included a total of 137 patients aged 1837 years.
 RESULTS: In group 1, the average caries intensity was 18.20.5; non-carious dental lesions, 9.00.4; periodontal tissue pathology, 90.60.6. In group 2, the corresponding values were 16.70.8, 4.50.3, and 85.50.8, respectively. In CG, the incidence of these pathologies as 20% to two times less. By sex groups, a more severe form of periodontal tissue inflammation was noted in women, and after age 45 years and onset of menopause, it increased to 66.6%. The minimal thickness of the cortical layer was recorded in patients with decreased bone mineral density (BMD) of the jaw bones, with 5.80.4 mm in group 1, 5.20.6 mm (p 0.001) in group 2, and 2.80.3 mm (p 0.001) in СG.
 CONCLUSIONS: Thus, in groups 1 and 2, the state of hard tissues against the background of reduced BMD is characterized by high rates of extracted teeth. In addition, specific changes in periodontal tissues were noted, i.e., aggressive disease course, deterioration of all periodontal indexes, increased attachment loss, and higher degree of bone tissue resorption, which are characteristic of severe periodontal pathologies. In addition, an imbalance in the calcium-regulating hormone system was noted in middle-age adults in groups 1 and 2 of both sexes. In our opinion, the cause was a disorder of the bone remodeling cycle in the presence of an imbalance in calcium-regulating hormones.