Stability of surgical correction of patients with Skeletal III and Skeletal II anterior open bite, with increased maxillary mandibular planes angle.

The surgical correction of eleven Class III patients and 10 Class II patients with a long face, increased maxillary mandibular planes angle and anterior open bite was undertaken using bimaxillary surgical procedures. Lateral skull radiographs were examined pre-operatively, 48 hours, and 1 year post-operatively, to quantify the amount and direction of surgical change achieved and the subsequent stability. There was no consistent pattern in the actual movements achieved in either group of patients in the maxillae or the mandibles. Some of the cases being impacted and continuing to impact, others impacting then relapsing. In the Class III patients some of the mandibular set backs remained stable others relapsing and some continuing to move posteriorly. However, despite these inconsistent patterns, there was a 7-degree reduction in the maxillary mandibular planes angle which relapsed by 1.7 degrees over the first year. The overbite was increased from -6 mm to +3.1 mm post-operatively and this relapsed at the 1 year stage to +2.4 mm. The overjet reduced from -4 to 1.7 mm and continued to improve to -0.9 mm at the 1-year stage. In the Class II patients some of the mandibular advancements remained stable others relapsing and some continuing to advance. However, despite these inconsistent patterns there was a 9-degree reduction in the maxillary mandibular planes angle which reduced by a further degree at the 1 year stage. The overbite was increased from -4.6 to -1.6 mm post-operatively and this remained stable at the 1 year stage.(ABSTRACT TRUNCATED AT 250 WORDS)