Does rapid maxillary expansion induce adverse effects in growing subjects?

Objective: To assess the scientific evidence that rapid maxillary expansion (RME) causes Adverse Effects on the midpalatal suture, vertical dimension, dental and periodontal structures in growing subjects. Materials and Methods: Electronic databases were searched for articles dated through December 2011. The quality of the studies was ranked on a 13-point scale in which 1 was the low end of the scale and 13 was the high end. Results: Thirty relevant articles were identified. The amount of midpalatal suture opening ranged from 1.6 to 4.3 mm in the anterior region and from 1.2 to 4.4 mm in the posterior region. At the end of the active phase, RME resulted in slight inferior movement of the maxilla (SN-PNS +0.9 mm; SN-ANS +1.6 mm), increased tipping of anchored teeth from 3.4° to 9.2°, and bending of the alveolar bone from 5.1° to 11.3°. In the long term, RME did not modify the facial growth patterns, and no significant changes on dentoalveolar structures were observed. Of the 30 studies, 2 were medium-high quality, 8 were medium quality, and 20 were low quality. Conclusions: RME always opened the midpalatal suture in growing subjects. The vertical changes were small and transitory. In the long-term evaluation, an uprighting of anchored teeth was observed and periodontal structures were not compromised.