Effects of maxillary protraction with or without expansion on the sagittal pharyngeal dimensions in Class III subjects

Introduction: The aim of this cephalometric study was to analyze the effects of rapid maxillary expansion (RME) and facemask (FM), or FM combined with bite block (BB), on the sagittal pharyngeal dimensions in subjects with Class III malocclusion when compared with an untreated Class III control group. Methods: Thirty-nine subjects (22 girls, 17 boys) were divided into 2 groups: the FM/BB group (22 subjects; mean ages, 8.9 years ± 1.5 before treatment and 10.5 years ± 1.3 after treatment) and the RME/FM group (17 subjects; mean ages, 7.1 years ± 1.8 before treatment and 9.2 years ± 1.8 after treatment). The treated groups were compared with an untreated Class III control group of 20 subjects (mean ages, 8.1 years ± 1.2 at the first observation and 10 years ± 1.7 at the second observation). All subjects were at prepubertal stage of skeletal maturity at both times. Comparisons of these changes between the 3 groups were analyzed with the Kruskal-Wallis 1-way analysis of variance (ANOVA) on ranks with post-hoc tests. Results: The favorable skeletal maxillary and mandibular changes produced by maxillary protraction with or without RME were not associated with significant changes in the sagittal oropharygeal and nasopharyngeal airway dimensions. Conclusions: Orthopedic treatment of Class III malocclusion does not produce a significant increase in airway dimensions in the short term.