Evaluation of the long-term effects of the 'twin force bite corrector' use in self-ligating bracket systems on joint position and lateral cephalometric values

The purpose of this study is to evaluate the effects of Twin Force Bite Corrector fixed functional appliance on lateral cephalometric measurements and condyle position by comparing self-ligating (Damon) and conventional (MBT) brackets. The study included 29 subjects (mean age 12,3) which is randomly separated into two groups, self-ligating Damon Brackets (mean age 12,4) and conventional MBT brackets (mean age 12,7). Lateral cephalometric radiographs and centric relation-centric occlusion records, used for establishing condyle position, are analyzed at 3 stages: pretreatment (T0), postreatment (T1), follow-up period after treatment (T3). 87 lateral cephalometric radiographs and 87 centric relation-centric occlusion records are evaluated. The average total follow-up period is 2 years and the duration of follow-up does not show significant diffrerences in two groups. Restraining maxillary growth, improvement of maxillomandibular changes, counterclockwise rotation of the occlusal plane, reduction of overjet and overbite, posterior movement and retroclination of maxillary incisors, proclination, anterior movement and intrusion of mandibular incisors, intrusion and distal movement of maxillary molars are reported on patients who are treated with TFBC appliances in the long term. No statistical significant changes have obtained in vertical facial parameters and mandibular sagittal position. Post-treatment at follow-up, a statistically significant relaps of overjet was observed in the amount of 0,51 mm depending on anterior movement and proclination of maxillary incisors, posterior movement and retroclination of mandibular incisors. While the effects of TFBC appliance is compared in two groups, in the short term, angle of anterior face height increases more in MBT group than Damon group. In the long term angle of FMA increases more in MBT group. While the effect in condyle position of TFBC appiance is evaluated, the amount of condylar displacement was significantly decreased after treatment and follow-up period both vertical and horizontal directions on the patients who diagnosed out of physiologic limits before forsus treatment. There were no significant differences on the patients who diagnosed within physiologic limits before treatment, after treatment and follow-up period.