The acrylic-splint Herbst appliance: a cephalometric evaluation.

The purpose of this study was to investigate the skeletal and dental effects of the removable acrylic-splint Herbst appliance cephalometrically. Radiographs of 46 patients were collected, traced, digitized, and analyzed. Cephalometric measurements indicated that the treatment group was Class II before treatment and Class I after treatment, with no change in the vertical skeletal pattern. There was significantly more mandibular growth (Co-Gn) than in an untreated Class II control sample (P < or = 0.001), and less forward maxillary growth (nasion perpendicular to A) (P < 0.05). Molar correction was obtained by 21% more skeletal change and overjet correction by 25% more skeletal change than reported for the banded Herbst. Patients with higher mandibular plane angles had greater correction of Class II indicators than did patients with low angles. There was no significant change in the sagittal position of the condyle.