The headgear effect of the Herbst appliance: a cephalometric long-term study.

The short- and long-term effects of the Herbst appliance on the maxillary complex were evaluated in 45 patients who had Class II malocclusions. The patients were followed for 6.4 years (5 to 10 years) after treatment. Lateral cephalograms from before and after 7 months of treatment, 6 months, and 6.4 years after treatment were analyzed. During Herbst treatment the upper molars were distalized in 96% of the subjects (maximum 4.5 mm), and the upper molars were intruded in 69% of the subjects (maximum 3.5 mm). The maxillary occlusal plane was opened in 82% of the subjects (maximum 7.5 degrees). Sagittal maxillary jaw base position seemed unaffected by therapy. A downward tipping of the palatal plane was noted in 47% of the subjects (maximum 2 degrees). During the first 6 months after therapy most of the treatment changes reverted. During the following 5.9 years after treatment, normal growth developmental changes prevailed: the upper molars moved mesially, and the teeth extruded, the occlusal plane closed, the maxilla grew anteriorly, and the palatal plane tipped downward. In conclusion the Herbst appliance exhibited a pronounced high-pull headgear effect on the maxillary complex. Without proper retention, however, the effect seemed to be of a temporary nature.