Long-term effects produced by early treatment of Class III malocclusion with rapid maxillary expansion and facemask followed by fixed appliances: A multicentre retro-prospective controlled study

Objective: To assess the short- and long-term dentoskeletal effects of early Class III treatment with rapid maxillary expansion and facemask (RME/FM) followed by fixed appliances.Materials and Methods: A total of 44 patients (27 females, 17 males) treated consecutively with RME/FM were included from the archives of 3 centres. Three lateral cephalograms were available: T0 (before the start of RME/FM therapy, mean age 8.1 +/- 1.8 years), T1 (immediately after RME/FM, mean age 9.8 +/- 1.6 years), and T2 (long-term observation, mean age 19.5 +/- 1.6 years). A control group of 17 untreated Class III subjects (12 females and 5 males) also was selected. Between-group statistical comparisons were performed with ANCOVA.Results: No statistically significant differences for any of the cephalometric variables were found at T0. In the short term, the treated group showed significant improvements in ANB (+2.9 degrees), Wits appraisal (+2.7 mm), SNA (+1.8 degrees) and SNB (-1.1 degrees). A significant closure of CoGoMe angle (-1.3 degrees) associated with smaller increments along Co-Gn (-2.4 mm) also was found together with a significant increase in intermaxillary divergence (+1.3 degrees). In the long-term, significant improvements in ANB (+2.6 degrees), Wits appraisal (+2.7 mm) and SNB (-1.7 degrees) were recorded together with a significant closure of the CoGoMe angle (-2.9 degrees). No significant long-term changes in vertical skeletal relationships were found.Conclusions: RME/FM therapy was effective in improving Class III dentoskeletal relationships in the short term. These changes remained stable in the long-term due mainly to favourable mandibular changes.