Premature removal of baby teeth is one of the main causes of deformation of the dentition. The loss of the first temporal molars is most often reported (39.9±4.8%), which leads to displacement of the teeth bordering on the defect, narrowing and shortening of the dental arch, which then leads to retention of premolars, cutting out permanent canines outside the dental arch, pathology of cutting out permanent molars. The aim of the study was to evaluate the biomechanics of permanent teeth migration in patients who prematurely lost their first temporal molars. An anthropometric study of jaw models and orthopantomograms was conducted in 25 patients (age 7-12 years) who had premature loss of the first temporal molars of the upper and lower jaws (age 7-12 years). Complications were evaluated, regularity was revealed and the biomechanics of permanent teeth displacement as a result of the prolonged absence of temporary molars were determined.