Longitudinal effects of rapid maxillary expansion

OBJECTIVE: To evaluate the long-term effects of rapid maxillary expansion (RME) via banded expanders in the sagittal and vertical facial planes. MATERIALS AND METHODS: The sample consisted of 25 patients who had undergone RME (with either Haas-type or Hyrax hygienic expanders) followed by standard edgewise orthodontic therapy. This sample was compared with a group of 25 patients who had edgewise treatment only and with a control nontreatment group of 26 subjects, matched by age and gender with the patients of the other two groups. Lateral cephalograms were taken before treatment (T1), at the end of treatment (T2), and at 3 years posttreatment (T3), comprising a 5-year average time of observation. RESULTS: RME treatment, in the long-term, did not influence the sagittal position of the apical jaw bases or the facial vertical dimension. CONCLUSION: Unfavorable cephalometric changes resulting immediately after RME are temporary, and therefore concerns about using RME in patients with vertical growth patterns or an extremely convex facial profile are not substantiated.