Evaluation of the effects of the twin force bite corrector using with self-ligating brackets on condylar position and lateral cephalometric measurements

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 32 subjects (mean age 13,6) which is randomly separated into two groups, self-ligating Damon Brackets (mean age 12,7) and conventional MBT brackets (mean age 12,6). Lateral cephalometric radiographs and centric relation-centric occlusion records, used for establishing condyle position, are analyzed at 4 stages: pretreatment (T0), before TFBC (T1), after TFBC (T2) and postreatment (T3). 128 lateral cephalometric radiographs and 128 centric relation-centric occlusion records are evaluated. The average total treatment time is 16 months and the duration of treatment does not show significant diffrerences in two groups. Restraining maxillary growth, improvement of maxillomandibular changes, clockwise 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. No statistical significant changes have obtained in vertical facial parameters and mandibular sagittal position. While the effects of TFBC appliance is compared in two groups, angles of SNA, ANB, IMPA and Wits appraisal and lower face height decreases more and occlusal plane clock-wise rotate more in Damon group than MBT group. While the effect in condyle position of TFBC appiance is evaluated, it is discovered that the shift of centric relation and centric occlusion ratio is %40 in initial phase and then this ratio decreases to %21 at the end of the treatment. The amount of sagittal discrepancy of right and left condyle is greater in pretreatment than postreatment phase. Key Words: Condyle position, Conventional brackets, Self-ligating brackets, Twin Force Bite Corrector, Centric relation, Centric discrepancy