A randomized controlled clinical trial will be conducted to address the aim of the study. Thirty-nine growing patients with skeletal Class II malocclusion due to mandibular retrognathism will be recruited. The sample will be randomly allocated to three equal groups, each including thirteen subjects. Group A will be treated by pushing orthopedic force mechanics using fixed functional appliance (Sabbagh Advanced Repositioning Appliance) anchored to four miniplates (two miniplates inserted in the mandibular symphysis and two infrazygomatic miniplates), and Group B, will be treated by pulling orthopedic force mechanics using Class II springs (CS Class II correction device) anchored to four miniplates (two inserted in the mandibular posterior buccal segment and two inserted in the maxillary anterior segment). In both groups, the appliances will be removed after reaching an edge-to-edge incisor relationship or after 9 months, whichever happens first. A similar third group (Group C) will be observed for 9 months to detect the natural growth changes. Skeletal changes will be evaluated using pretreatment and posttreatment cone beam computed tomography scans (CBCT). The treatment changes will be compared with the natural growth changes observed in group C. Other variables will be also examined including, the dentoalveolar effects, the soft tissue profile, and the patient's acceptance to this treatment modality.
Patients with skeletal Class II malocclusion due to mandibular retrognathism will be recruited and randomly allocated to three equal groups. first group will be treated by pushing orthopedic force mechanics, second group will be treated by pulling orthopedic force mechanics, and third group will be observed for 9 months to detect the natural growth changes. Skeletal changes will be evaluated and the treatment changes will be compared with the natural growth changes. The study hypothesis is that use of direct bimaxillary miniplate anchorage in conjunction with fixed functional appliance (pushing orthopedic force) or closed coil spring (pulling orthopedic force) will induce statistically significant skeletal mandibular growth in comparison to natural mandibular growth changes.