Thus, the aim of the presented study is to increase the effectiveness of fixed dentures by optimizing the method of preparation of supporting teeth in patients with generalized periodontitis.
To realize the aim and tasks, the work was carried out in three stages. At the first stage, for determination of the need for prosthetic treatment and description of the clinical and functional status of supporting teeth in generalized periodontitis, 300 persons under the age of 45 who applied for dental prosthetics were examined. In addition to the clinical examination it was used computer tomography and computer occlusiography.
At the second stage of the work, the peculiarities of movements and stress distribution were studied when covering the lower central incisor with a metal-ceramic crown, considering the conic angle of the preparation and the degree of destruction of the alveolar bone using the finite element method. Computer models were created by means of the calculation software complex "Lira 9.6" to reproduce an intact (before preparation) tooth, prepared tooth and covered with a metal-ceramic crown. The calculation was carried out for different angles of convergence, starting from 2⁰ to the maximum possible, for four types of loads (constant one from own weight; vertical from biting food; at an angle of 30⁰ and 45⁰ to the vertical) and for different degrees of alveolar preservation: 100 %, 75 % and 50 %. Thus, in the process of research, 36 calculation models were obtained, which differed from each other in the presence of the artificial crown, features of tooth preparation, degree of alveolar preservation and type of load.
At the third stage of the work (clinical approbation), the content of pro-inflammatory cytokines and MMP-8 in the gingival fluid and bone metabolism indicators in the blood serum of patients with generalized periodontitis after fixation of dentures were investigated. The metal-ceramic dentures were made for 30 patients with generalized periodontitis of the I-II degree of severity, chronic course, aged 32-45 years, equally women and men. Clinical and laboratory examinations of patients were carried out before dental prosthetics, after preparation of supporting teeth and at the end of prosthetic treatment – in 2-3 days after fixation of dentures (the nearest period of observation) and in 6 and 12 months (the long term). To learn the dynamics of periodontal status, the content of pro-inflammatory cytokines IL-1β, IL-6, TNF-α and MMP-8 in gingival fluid samples was studied. To describe the state of bone tissue, the activity of tartrate-resistant acid phosphatase (TRAP) and bone alkaline phosphatase (BAP), the content of osteocalcin and C-terminal propeptide of type I procollagen, were determined in blood serum.
The obtained results of clinical, functional and biochemical studies were processed using MS Excel 2016 and Statistica 6.1.
Therefore, the conducted clinical and laboratory research proved that dental prosthetics against the background of generalized periodontitis, which involves the rational preparation of supporting teeth, makes it possible to stabilize the periodontal status and inhibit the progression of the inflammatory and destructive process in the periodontal tissues.
