What does headgear add to Herbst treatment and to retention?

Abstract

This study was designed to investigate the effect of adding headgear to the Herbst appliance and the retainer, respectively. The material comprised 2 samples of consecutively treated patients with skeletal Class II malocclusions. The first sample of 22 patients (mean age, 13.2 years) was treated with high-pull headgear Herbst appliance followed by a headgear activator as a retainer, and the second sample of 14 patients (mean age, 12.9 years) was treated with Herbst appliance and an Andresen activator for retention. In both groups, the Herbst appliance was a cast silver splint type with step-by-step advancement of the mandible. Before treatment, there were no significant differences in dentofacial morphology between the groups. Changes during treatment and retention were assessed from lateral cephalograms obtained at start of treatment, after 6 months of treatment, end of treatment (12 months of treatment), and after 6 months of retention. The results showed that the maxillary forward growth was more restrained after 6 months and increasingly more during the 12 months of treatment in the headgear Herbst group, resulting in greater improvement of the jaw-base relationship in that group. The maxilla tilted in the Herbst group but not in the headgear Herbst group. During retention, the positive skeletal changes achieved during active treatment were maintained with the headgear activator, whereas with the Andresen activator there was partial relapse. The overjet correction was similar in both groups, being 9.0 and 9.7 mm, respectively. With the combined headgear concept, 70% of the overjet correction was caused by skeletal changes, whereas in the other group the skeletal contribution was less than 30%. In conclusion, adding headgear to the Herbst resulted in increased orthopedic effect on the maxilla and larger improvement of the jaw-base relationship. The choice of the retention device was critical; the headgear activator maintained the treatment results, whereas the Andresen activator had a negative effect and should not be used as a retainer after Herbst treatment.