Effect Of Modified Twin Block Appliance On Incisor Torque

To study the effect of the modified twin block activator on incisor torque in the treatment of distoclusion. In the study 55 patients with skeletal distoclusion were examined. Of these, 28 orthodontically treated patients formed the study group, while 27 untreated patients served as the control group. Patients were aged 10-14 years (mean: 11.78±0.91), with treatment lasting 1.5–2 years (mean: 1.82±0.43). To evaluate changes in the incisor torque, cephalometric analysis was performed pre- and post-treatment in the study group and at a two-year interval in the control group. In the study group, the upper incisors showed a retrusion of -7.25±4.97 degrees, while in the control group, a protrusion of 0.95±2.02 degrees was observed. The upper incisor/PL angle showed a retrusion of 6.54±5.42 degrees. The lower incisors exhibited a protrusion of 4.95±3.41 degrees in the study group, and 1.92±2.55 degrees in the control group due to natural growth. Based on the lower incisor/A-Pg distance, the study group had a protrusion of 0.97±1.53mm, while the control group had 0.59±0.87mm. We believe that retrusion of upper incisors occurs due to the effect of the vestibular arch of the proposed appliance. Although lower incisor protrusion is undesirable, it occurs as a side effect. To minimize this, adding a vestibular arch to the lower section of the activator is recommended.