Topicality. Dental morbidity continues to remain at a high level, the complication of which is partial loss of teeth. Orthopedic patient treatment after the manufacture of fixed dentures requires a special approach, since each orthopedic construction has certain retention elements for food residues and, thus, contributes to the violation of the hygienic condition of the oral cavity, the active formation of a biofilm with the phenomenon of «Quorum Sensing». One of the methods of optimizing the condition of the oral cavity and the periodontal tissues of supporting teeth is the use of photodynamic therapy. At the same time, the issue of using photodynamic therapy in the presence of dental prostheses in the oral cavity remains insufficiently studied, which determines the relevance of our research. The purpose of the study is to increase the effectiveness of orthopedic replacement of tooth row defects and prolong the period of use of fixed dental prostheses by using supportive photodynamic periodontal therapy of abutment teeth. Materials and methods. The research was conducted at the Department of Dentistry of the Institute of Postgraduate Education of the O.O. Bogomolets National Medical University, the Department of Dentistry of the National University of Health Protection of Ukraine named after P. L. Shupyk, and «Academic Dentistry» LLC, Kyiv. We observed 58 people of three age groups: 30–44 years, 45–59 years, and 60 years and older, including 22 men and 36 women with included dental defects, who were made bridge-shaped prostheses. The control group (III group) included 22 people of the same age groups with intact dentitions and physiological forms of bite, who had intact dentitions without clinically diagnosed periodontal tissue diseases and teeth affected by the carious process. 25 people (group I) underwent prosthetics after traditional therapeutic training and professional oral hygiene prior to prosthetics, and, according to clinical indications, periodontal treatment. 22 persons of the II group, were additionally prescribed photodynamic therapy of the periodontal tissues of the abutment teeth, which was applied before applying and during the period of use of orthopedic construction. For photodynamic therapy, the «Lika-Therapeut-M» dental system was used, which includes a laser with a wavelength of 660 nm and a toluidine blue preparation. To ensure the therapeutic photobiological effect directly in the periodontal tissues, before starting the photodynamic therapy procedure, professional oral hygiene was performed. The results. Prosthetics of a group of patients with the appointment of sessions of photodynamic therapy, which is applied before applying and during the period of use of orthopedic constructions in comparison with the results of prosthetics without any supporting periodontological therapy of supporting teeth, indicate an improvement in the hygienic state of the oral cavity, a reduction in inflammatory-dystrophic changes in the periodontal tissues supporting teeth during the period of use of orthopedic constructions, which allows to avoid recession of the gingival edge of teeth covered with artificial crowns and, accordingly, prolong the period of use of fixed orthopedic constructions. Conclusions. The use of fixed dentures due to the retentive properties of the intermediate part of the bridge-like dentures contributes to the deterioration of oral cavity hygiene and, accordingly, biofilm with the phenomenon of "Quorum Sensing", which requires the use of professional oral hygiene and effective oral hygiene lessons. In case of using artificial crowns, inflammatory and destructive changes in the marginal edge of the gums occur, for the prevention of which it is advisable to use photodynamic maintenance therapy of the periodontium of supporting teeth. The appointment of sessions of photodynamic maintenance therapy, which is used before applying and during the period of use of orthopedic constructions, contributes to the improvement of the hygienic condition of the oral cavity, the reduction of inflammatory and dystrophic changes in the periodontal tissues of supporting teeth during the period of use of orthopedic constructions, which allows to avoid recession of the gingival margin of teeth covered with artificial crowns and , respectively, to prolong the period of use of fixed orthopedic constructions. Keywords: bridge fixed dentures, prevention of complications, photodynamic therapy, periodontal tissues.