Treatment effects of simple fixed appliance and reverse headgear in correction of anterior crossbites.

Abstract

The aim of this study was to compare the skeletal and dental changes contributing to the correction of Class III malocclusion using a 2 x 4 appliance and reverse headgear in the mixed dentition. Seventeen consecutive patients (mean age, 9.7 years) with pseudo-Class III malocclusions and an anterior functional shift and straight or concave facial profile were treated with a simple fixed appliance. Another 20 consecutive patients (mean age, 8.5 years) with Class III incisor relationship and straight or concave facial profiles, were treated with reverse headgear. Lateral cephalometric films taken at the beginning of treatment, the end of the treatment, and 1 year after the active treatment, were analyzed with the modified Pancherz analysis. After active treatment, the overjet correction, 5.2 mm and 6.5 mm on average, respectively, were achieved using the 2 x 4 and reverse headgear. The overjet correction by the 2 x 4 appliance was due to dental changes only. In the reverse headgear group, 60% of the overjet correction was due to dental changes and 40% due to skeletal changes. During the 12 months follow-up period, the overjet was unchanged in the 2 x 4 group (1.6 mm) and decreased in the reverse headgear group, the difference being statistically significant (P <.05). The change of jaw relationship was similar between the 2 x 4 and reverse headgear groups. During the follow-up period, a decrease in overjet in the reverse headgear group was mainly due to forward growth of the mandible and proclination of lower incisors. The overjet in the 2 x 4 group was unchanged due to dental compensation (1.6 mm). To conclude there was a similar amount of overjet correction in the 2 x 4 and reverse headgear groups. Overjet correction by the simple fixed appliance was produced by dental changes whereas in the reverse headgear group, it was produced by both dental and skeletal changes.