Dento-skeletal Effects of Clear Twin Block Treatment at Specific Period in Growing Patients

Aim: To investigate the dento-skeletal effect of clear twin block in patients wearing the appliance at specific period. Methods: A total of 40 patients (regardless patients sex) with an age ranged from 9 to 12 years with class Ⅱ Div1 mal-occlusion and class 2 skeletal pattern will be included in the study. All the essential diagnostic records will be taken (for each patient) including: 1. Pre-operative and post-operative photographs. 2. Pre-operative and post-operative cephalometric radiographs. 3. Pre-operative and post-operative digital models. Another secondary records will be taken include: 1. Pre-operative hand and wrist radiograph. 2. Pre-operative and post-operative cone beam computed tomography (CBCT) Each patient will wear the appliance for 3 months with 16 hours per day wearing time. All patient's parents will assign an informed consent describing the treatment protocol. The following parameters will be assessed: 1. Over bite, over jet, inter-canine width and inter-molar width differences on digital models. 2. SNA, SNB, ANB, AO-BO and A-B Chang differences on lateral cephalometric radiographs. 3. Changes on condylar head and permanent first molar root resorption on CBCT.

Inclusion Criteria: * age ranged from 9 to 12 years * class Ⅱ Div1 mal-occlusion and class 2 skeletal pattern Exclusion Criteria: * Adults (passing the puberty) * Refuse to participate in the study * Uncooperative patients