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

The aim of this study was to compare the skeletal and dental changes contri buting 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 yea rs) with Class III incisor relationship and straight or concave facial prof iles, 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. Af ter 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 over jet correction by the 2 x 4 appliance was due to dental changes only. In th e reverse headgear group, 60% of the overjet correction was due to dental c hanges and 40% due to skeletal changes. During the 12 months follow-up peri od, 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 overje t in the reverse headgear group was mainly due to forward growth of the man dible and proclination of lower incisors. The overjet in the 2 x 4 group wa s unchanged due to dental compensation (1.6 mm). To conclude there was a si milar amount of overjet correction in the 2 x 4 and reverse headgear groups . Overjet correction by the simple fixed appliance was produced by dental c hanges whereas in the reverse headgear group, it was produced by both denta l and skeletal changes.