Stability of rapid maxillary expansion in adolescence: A long-term evaluation following fixed appliances
Lazzara, David B.
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Background: Despite the popularity of rapid maxillary expansion (RME) in orthodontics, its long-term stability in adolescence remains controversial. Purpose: To investigate the long-term dental stability of adolescents treated with RME followed by fixed appliances. Research Design: Digital models were obtained from two groups of patients: a treated group with Hyrax RME followed by fixed appliances (TG) and a comparison group with fixed appliances only (CG). Maxillary and mandibular arch width, depth, palatal depth and molar tipping were measured at three time points: pretreatment (T1), completion of fixed appliance therapy (T2), and long-term recall (T3). Results: 126 Total models were obtained from 21 subjects with a mean follow-up of 3.4 ± 1 years. While the RME group had significantly narrower maxillary posterior widths pretreatment, no statistical differences were detected between groups at T2 or T3. Intermolar width long-term increased 4.24 ± 2.14 mm for TG, a significant increase over fixed appliances only (CG) 1.26 ± 1.99 mm. Maxillary intermolar width was found to relapse only 12% long-term (-0.61 ± 0.72 mm) with no clinical relapse detected between molars in CG. Relapse in arch depth, palatal depth and molar tipping were not significant. Conclusions: Hyrax RME in adolescence followed by fixed appliances is stable in the long-term and relapse is comparable to fixed appliances only.