Treatment and posttreatment effects of mandibular cervical headgear followed by fixed appliances in Class III malocclusion

Abstract

In this cephalometric investigation, we compared the treatment and posttreatment effects on patients undergoing an initial phase of mandibular cervical headgear (MCH) therapy followed later by comprehensive edgewise therapy with untreated Class III controls. The treated sample consisted of 21 patients treated consecutively with MCH before the pubertal growth spurt (average age, 10 years 2 months at the beginning of treatment). At the final observation period (average age, 15 years 3 months), all patients were in decelerative growth phases as determined by the cervical vertebral maturation method. Active treatment and posttreatment effects were evaluated in the treated group with nonparametric statistical analysis for paired samples. The treated sample was compared with a nonparametric statistical test for independent samples with 20 untreated Class III subjects who were matched for malocclusion, sex, and stage of cervical vertebral maturation to the treatment group. MCH therapy followed by fixed appliances was shown to be an effective treatment for the correction of skeletal Class III malocclusion at postpubertal observation. The favorable skeletal effects consisted mainly of smaller increases in mandibular length and advancement with respect to the controls, with the final outcome of significant improvements in the sagittal skeletal (+4 mm for the Wits appraisal) and dental (+2.7 mm for overjet, -4.4 mm for molar relationship) parameters. This treatment protocol also induced significant downward rotation of the mandible (2.8 degrees ).