Studying TMJ Changes After Using Twin Block Appliance for the Treatment of Class II Cases

Abstract

Twin block appliance was selected for treating 10 children displaying skeletal class II malocclusion, mandibular deficiency. MRI was then used to study the changes that occurs in the TMJ in response to the treatment. All included subjects were free of any TMJ problems. MRI was performed before starting treatment and after 8 months of using twin block appliance, for each patient. Sagittal concentricity, sagittal disc position and eminence angle were calculated for each patient from the MRIs. Insignificant differences were found for the sagittal concentricity, sagittal disc position and the eminence angle before and after treatment. When comparing sagittal concentricity, sagittal disc position and eminence angle for the right and left TMJs of each patient, significant difference was recorded either before or after treatment for the disc position while the results were insignificant for the rest.