Aim in order to analyze the effectiveness of orthodontic treatment in 7—9 years old children, dental status in children residents of Moscow was compared with 15—17 years adolescents with completed bite formation. Material and methods. The adolescents were divided into two groups: those who received orthodontic treatment during the mixed dentition period and those who did not receive the treatment. A WHO survey chart was used to assess the dental status of children (WHO, 2013) with additional section «Dentoalveolar anomalies». DMFT and DMFT+dft, OHI-S, CPI, PAR, Little irregularity index and DAI were assessed in all groups. The need for dental and orthodontic treatment was calculated. Results. Dental morbidity in Moscow children during the mixed dentition period was characterized by a high prevalence of caries (92.0%) with an intensity of 1.67±0.03, the 17.0% prevalence of premature teeth loss and dentoalveolar anomalies in 73.9% of children with a combination of anomalies in 60.8% of children. Orthodontic treatment in the mixed dentition period is associated with systematic professional control and by the age of 15 years results in two-fold reduction in the intensity of caries and periodontal disease, proper detection of poor hygiene and the lower prevalence of abnormal positioning of the teeth (crowding and misalignment of teeth) and the improvement of dental arches ratio (completely eliminating cross-bite). At the same time early orthodontic treatment has no significant effect on the prevalence of tooth rotation, interdental spaces, deep, open, distal, mesial occlusion and displacement of dental arches. Conclusion. Orthodontic treatment of children during the mixed dentition period is indicated in cases of crowding and displacement of teeth, as well as cross-bite; with respect to other types of dentoalveolar anomalies, early orthodontic treatment is only justified by the severe impact of dentoalveolar anomalies on psychological and functional indicators.