The aim of the study was to determine the likelihood and frequency of complications, the impact of the use of various types of toothbrushes in the dynamics of orthodontic treatment with fixed appliances in patients with a distal permanent bite. The clinical study was conducted on 63 patients of both sexes, aged 11—18 years. Patients received long-term orthodontic treatment for a close tooth position with a distal permanent bite (K07.2) and cleft palate and lip (Q37.1). Three groups were conditionally distinguished depending on the type of toothbrush used for individual oral hygiene: group 1 (n=21) — an orthodontic manual toothbrush (Professor Persin, Spazzolificio Piave S.p.A, Italy); Group 2 (n=22) — an ultrasonic toothbrush (Emmi-dent, EMAG AG, Germany) and group 3 (n=20) — an electric toothbrush (Oral-B Pro-Expert, Procter & Gamble, USA). According to the Kaplan—Meier method, the probability of developing complications of orthodontic treatment was calculated as patients wear braces, and the impact on the effectiveness of orthodontic treatment of using toothbrushes of various types was evaluated. A frequency analysis of the complications of orthodontic treatment for the entire period of wearing fixed orthodontic structures revealed a difference only in respect to enamel demineralization. In group 1, enamel demineralization was more common (42.9%) compared with 2 (9.1%) and 3 (25%) groups (p=0.039). The likelihood of developing gingivitis was higher in group 1, the timing of the development of inflammatory processes in periodontium was also shortened in group 1 compared with groups 2 and 3. The frequency and timing of the development of gingivitis and enamel demineralization depended on the type of toothbrush used in daily oral hygiene. A marked deterioration in the oral hygiene during orthodontic treatment using a manual brush was accompanied by a more frequent development of gingivitis and enamel demineralization.