PRINCIPLES OF ORTHODONTIC TREATMENT OF PATIENTS WITH CONGENITAL UNILATERAL CLEFT UPPER LIP AND PALATE: BIOMECHANICAL JUSTIFICATION

Background. Treatment of children with congenital cleft lip and palate (CLP) begins at birth and continues until adulthood, requiring a multidisciplinary approach. Each of the stages of orthodontic interventions has certain features. Aim: to conduct a biomechanical substantiation of the principles of orthodontic treatment of patients with unilateral CLP. Material and methods. An interdisciplinary approach was analyzed and a biomechanical justification of the principles of orthodontic treatment of 137 children (average age 9.3±4.2 years) was given, using the example of patient Р., who applied to the clinic at the age of 5 with a diagnosis of congenital left-sided cleft upper lip, alveolar process, hard and soft palate after cheilorhinoplasty and veloplasty. Results. A complex diagnostic examination of patients with CLP included collection of anamnesis, clinical subjective and objective methods. A simulated and discrete model was created to simulate the movements of parts of the biomechanical system, which included the orthodontic appliance and the upper jaw, from 360° angular movements. At the same time, calculated force vectors with an amplitude of 50 N were used. The X-ray density of the compact layer of bone tissue under the influence of loads was determined. Characteristic features of the formation of dentognathic deformities in patients with CLP and the dynamics of their orthodontic treatment were revealed using morphometric and anthropometric measurements of scanned models of jaws. Conclusion. In the treatment of children with CLP, it is important to follow a coordinated rehabilitation algorithm; success depends on timely and topographically and functionally prepared surgical interventions and consistent orthodontic correction with the determination of patterns of changes in the stress-strain state and the magnitude of deformation displacements of unfused fragments of the upper jaw.