Doroshenko N. The usage of the movable ramps in the treatment of sagittal malocclusion

The purpose of the dissertation was to increase the efficiency and reduce the number of complications during the sagittal malocclusion treatment in the transitional bite period by the diagnostics improving, developing of movable ramps in orthodontic appliances and indicating cases for their usage. Clinical, anthropometrical, statistical, functional, mechanical, mathematical investigation methods and X-ray were used to achieve the study tasks. Epidemiological examination of 724 children of age 6-12 years revealed that dental apparatus anomalies and deformations were present in 641 cases (88.54 %). Distal occlusion was found in 51.93 % cases, mesial - in 7.32 % cases. To improve functional treatment methods, the removable orthodontic appliances with the movable ramp were created (declarative patent of Ukraine № 99388 from 25.05.2015). The appliance's design includes a plastic basis, vestibular arc, retaining clasps and the movable ramp which is connected with the base via two torsion (club-shaped) springs. To evaluate the effectiveness of the proposed construction in the treatment of sagittal bite pathology in a mixed occlusion period comparing to the standard equipment we've took for the treatment 98 patients - 68 with mesial bite and 30 with distal bite. They were divided into two groups - main group and comparison one. The main group was treated by removable orthodontic appliances with the movable ramp, and the comparison group - with standard orthodontic equipment. The jaws models anthropometric studies were conducted before and after orthodontic treatment by using Nance, Huckaba and Mirhazizov's method. The result data was separated depending on the examination results before the treatment. Also, the Sassouni Рlus analysis with the program RadiocefStudio2 was used. This method includes investigation of linear, angular and radius parameters with a high level of the results individualization. Also, a superimposition of cephalometric images before and after treatment by structural landmarks (supraorbital plane Cl-RO and Si) was performed. Сephalometric analysis was made before and after treatment and revealed that appliance with a movable inclined plane allows improving teeth sagittal relationship in the frontal area among patients with mesial occlusion mainly on the dentoalveolar level but also with upwards movement of the mandible condyles up and their small sagittal retraction. Thus, the appliance with a movable ramp allows to improve the overjet ratio on the dental alveolar level by changing the torque of the upper frontal teeth and allows to move forward the lower jaw while treatment of patients with distal occlusion. The stability and degree of this displacement depend on the duration of treatment and the patient's ability to follow recommended time of usage.