Dentoskeletal changes of anterior openbite cases treated by intrusion of maxillary posterior segments via zygomatic miniplates

Introduction: No one can deny that the successful skeletal open bite treatment depends mainly on intrusion of maxillary buccal posterior segment and an anchorage system. So, intrusion of maxillary posterior segment was a magical orthodontic treatment mechanics granting a clock-wise rotation of the mandible, consequently closure of anterior open bite and improvement of facial profile convexity. So, the aim of this study is to evaluate skeletal and dental effects of intrusion of maxillary posterior segment by surgical miniplates. Materials and Methods: The selected sample size was ten patients (4 males and 6 females), ranging from 18 to 29 years of age (22.4 years, SD + 3.20 years), with skeletal anterior open bite were treated by intrusion of maxillary buccal posterior segment with surgical miniplates assisted intrusive device system which composed of zygomatic miniplates (Anchor unit), bonded acrylic maxillary hyrax expander with bite blocks (Reactive unit) and Nickel Titanium closed coil spring. Pre-treatment and Post-treatment lateral cephalograms were compared. Results: Maxillary first molars were intruded significantly by -3.85 mm + 0.82 mm(P<0.004). The lower anterior facial height was reduced statistically by -4.20 mm + 1.13 mm (P<0.005). Conclusion: The skeletal and dentoalveolar changes produced by zygomatic miniplate assisted maxillary buccal posterior segment intrusion were apparently impressive and sufficient for adult anterior open bite correction. The amount of intrusion produced by the current study was efficient to induce counter-clockwise rotation of the mandible. That amount of autorotation was enough to improve the retrognathic chin to be a prognathic one without the risk of orthognathic surgery.