Stepwise advancement Herbst appliance versus mandibular sagittal split osteotomy. Treatment effects and long-term stability of adult Class II patients.

OBJECTIVE To compare the treatment effects and long-term stability of the stepwise Herbst appliance and mandibular sagittal split osteotomy in skeletal Class II adult patients. MATERIALS AND METHODS Subjects comprised 16 patients in the Herbst group and another 16 patients in the surgery (mandibular sagittal split osteotomy) group. Lateral head films were taken before treatment (T0), after removal of the Herbst appliance/surgery (T1), after the fixed appliance treatment (T2), and 3 years after treatment (T3). All films were analyzed by standard cephalometrics and SO-analysis (analysis of changes in sagittal occlusion). RESULTS All Herbst and surgery patients were treated successfully to Class I occlusal relationships with normal overjet and overbite. Both groups showed a significant change in mandibular base advancement (SNB, SNPg, Pg/OLp), which resulted in a decrease in the ANB angle, the Wits appraisal, and facial convexity. However, the surgery group showed larger changes in the parameters mentioned above. In terms of long-term stability, both groups achieved stable results, and no significant difference occurred over time. CONCLUSION Stepwise advancement Herbst appliance therapy can be used to treat borderline skeletal Class II adult patients with long-term stability.