Effects of conventional and modified facemask therapies on dentofacial structures

Abstract

Objective: The purpose of this prospective study was to evaluate the dentofacial effects of conventional and modified facemask therapies with rapid maxillary expansion, in a group of Class III patients; and compared with an untreated control group. Methods: The conventional facemask group (Group 1) comprised of 24 patients, 13 girls and 11 boys (mean age, 9.2 ± 1.4 years); the modified facemask treatment group (Group 2) comprised of 24 patients, 12 girls and 12 boys (mean age, 9.3 ± 1.6 years); and the control group (Group 3) comprised of 21 subjects, 11 girls and 10 boys (mean age, 9.8 ± 1.9 years). Treatment and control changes within the groups and the differences between the groups were analyzed statistically. Intra-group comparisons were evaluated using the non-parametric Wilcoxons test and intergroup changes were analyzed using the Kruskal-Wallis test. The statistical significance of intergroup differences was further assessed with the Mann-Whitney test for independent samples and applying Bonferronis correction (p ＜ 0.016). Results: In group 1, SNB changes were less than the control. There were increases in SNA, ANB, SN-MP, A to N perp and Upper lip to E plane. In group 2, SNB, U1-NA (mm) U1-NA (o) and Pog to N perp (mm) changes were less than the control. There were increases in SNA, ANB, SN-MP, A to N perp and Upper lip to E plane. Conclusions: Modified facemask appliance can be used effectively in Class III patients with a retrognathic maxilla. Facemask therapies with expansion resulted in an anterior advancement and translation of maxilla without rotation; and the mandible moved downward and backward in both treatment groups. (Korean J Orthod 2010;40(6):432-443)