The aim of the study was to evaluate the effectiveness of antibiotic chemotherapy regimens and the dynamics of the nature of microbial associations of the operating area at the surgical stages of treatment of patients using dental implants in conditions of limited bone tissue. The study involved 37 patients (17 m and 20 w, from 32 to 68 years). According to the tactics of the treatment and the type of antibacterial effect, the patients were divided into 3 groups. Per os was prescribed antibiotics as a step therapy: amoxicillin (flemoxin 500 mg 1 tablet 2 per day for 7 days) and amoxicillin / clavulanate (flemoclav 625 mg 1 table 2 per day 7 days), doxycycline (unidox 100 mg 1 table 1 per day 5 days). The 1st group of patients (n1=12; 31.9%) — a multi-stage approach (MA), where the 1st operation is bone grafting (BG) (Flemoxin 500 mg), after 6—9 months, the 2nd dental implantation (DI) (flemoklav 625 mg), after 3—6 months the 3rd — installation of gingival formers (GF) (unidox 100 mg). The 2nd group of patients (n2=14; 36.2%) — a one-stage approach (OA), where the 1st operation is BG with simultaneous DI (flemoxin 500 mg), after 6—9 months — the 2nd — installation of GF (flemoklav 625 mg). 3rd group — narrow/short implants (N/S) without BG were installed (n3=11; 31.9%). The 1st operation — DI (Flemoxin 500 mg), the 2nd — installation of GF (Flemoklav 625 mg). A bacteriological study with the identification of pure cultures of bacteria and determination of sensitivity to antibacterial drugs was performed for all patients before treatment and in dynamics. In MA, there was a suppression of the growth of certain types of bacteria and an increase in the number of species resistant to this antibiotic. In the framework of the OA, when prescribing antibiotics, the results were comparable. With N/S implants, growth inhibition of a number of species present at the beginning of treatment was noted. In multi-stage operations, we consider it reasonable to use beta-lactamase-protected drugs, or drugs of another group that include representatives of parodontopathogenic species and potential carriers of multiple resistance genes in their spectrum of action.