Aim: The aim in this study was to treat anterior open bite by intruding the maxillary molars while not adversely affecting the smile with extrusion of the anterior teeth.
Method: The authors selected eight treatment patients (average age 13 years 1 month) and seven control patients (average age 11 years 9 months) to test their new method for anterior open bite correction. A modified full-coverage acrylic cap splint expander, with tubes at the premolar region, was cemented, and the screw was activated twice a day for 7 days. After expansion was achieved, occipital headgear was used with a newly designed facebow. The inner bows of the facebow were inserted in the buccal tubes on the cap splint and the outer bows were bent downward. The tips of the outer bows ended sagittally at the same level, between the root tips of maxillary first and second premolars. The force was directed upward and backward by the occipital headgear. This force design ensured an intrusive force on the maxilla and a clockwise moment, which contributed to the intrusion of the maxillary posterior teeth. The appliance was used for 6 months ± 2 weeks, followed by second-stage orthodontic treatment.
Results: The cephalometric results showed that the SN/MP angle decreased an average of 1.44 degrees (P < .05). The angle between the upper occlusal plane and SN (UOP/SN) increased an average of 6.88 degrees (P < .01) due to the clockwise rotation of the maxillary dentition. The SNB angle increased an average of 0.69 degrees (P < .05). The maxillary incisors were retroclined an average of 6.38 degrees (P < .01) with respect to the SN plane; they did not extrude significantly posttreatment. The maxillary first molars were intruded an average of 2.81 mm (P < .01) and the second molars were intruded an average of 2.13 mm (P < .05). Finally, the overbite was increased an average of 3.75 mm (P < .01) and the overjet was decreased an average of 3.94 mm (P < .01).
Conclusion: This appliance can be effective on patients with anterior open bite and excessive posterior maxillary growth.