Immediate post-treatment crowned Herbst effects in growing patients

OBJECTIVE. The aim of this prospective study was to describe the mechanism of Class II correction in growing patients induced by crown Herbst (cHerbst) appliance as an immediate result of therapy. MATERIALS AND METHODS. Forty patients (mean age 13.6 ± 1.3 years) with stable Class I occlusion 1 year following treatment with the cHerbst appliance were selected from a prospective sample of 180 consecutively treated Class II patients. No other appliances were used during treatment. The immediate dentoskeletal changes after discontinuing cHerbst therapy were compared with a matched sample of untreated Class II subjects (mean age 13.9 ± 1.6 years). Lateral cephalograms were taken before treatment and immediately after one year therapy. RESULTS. Treatment produced significant skeletal changes: increase in mandibular length and SNB angle, decrease of ANB angle, restricted growth of posterior maxilla. Significant dentoalveolar changes: maxillary molars moved backwards and tipped distally, lower first molars moved forward and extruded, lower incisors proclined, upper incisors retroclined, overjet and overbite decreased. CONCLUSIONS. Immediate postreatment results revealed that Class II was mainly corrected due to dentoalveolar changes and only limited skeletal change.