Methods: 30 non extraction Class II division I patients with a mean age 12.01 ± 1.24 years were treated with Twin Force Bite Corrector (TFBC) appliance. Lateral cephalograms were taken before orthodontic treatment (T1), before appliance placement (T2), at appliance removal (T3), and at the end of treatment (T4). All cases were treated with a Straight-Wire Appliance (0.022-inch slot appliance) MBT prescription with -6 degrees torque for lower incisors. Linear and angular measurements were made to determine the skeletal and dental effects. Statistical analyses were performed using dependent analysis of variance (ANOVA).
Results: On comparison of the changes between appliance effects (T3 –T2) and overall treatment (T4 – T1) significant (P˂0.05) differences were observed for SNA = -0.31& -1.22 degrees, ANB = -0.87 & -2.28 degrees and occlusal plane rotation = 5.34 & -2.01 degrees. Dentally significant difference (P˂0.05) was observed for upper incisor A-P= -1.67& -0.67mm, upper molar A-P= -1.16 & 0.78mm, upper molar vertically= -1.09 & 1.80mm and lower molar vertically= 1.17 & 3.09mm.
Conclusions: It was concluded that the findings suggested that the distal and intrusive effect of a fixed functional appliance on the upper incisors and upper molars were not stable during the course of the overall treatment. The distalization effect on the maxilla was stable and even continued after the appliance was removed.
Keywords: Class II and Orthodontics