The effectiveness of alternating rapid maxillary expansion and constriction combined with maxillary protraction in the treatment of patients with a class III malocclusion: a systematic review and meta-analysis

Objectives: To establish the effectiveness of Alternate Rapid Maxillary Expansion and Constriction combined with Protraction Facial Mask (Alt-RAMEC/PFM) approach in treating Class III growing patients compared with PFM combined with conventional Rapid Maxillary Expansion (RME/PFM). Search sources: Unrestricted search in five electronic databases and manual searching were undertaken up to February 2018. Data selection: Randomised clinical trials (RCTs) evaluating the effectiveness of Alt-RAMEC/PFM were selected. Data extraction: Screening of references, data extraction and assessment of bias risk were evaluated independently by two reviewers. Results: Five RCTs comparing the Alt-RAMEC/PFM with RME/PFM met the inclusion criteria. Small but statistically significant mean differences favouring Alt-RAMEC/PFM protocol as measured by SNA angle (1.16 degrees; 95% CI 0.65 to 1.66), SNB angle (0.67 degrees; 95% CI 0.32 to 1.02) and ANB angle (0.66 degrees; 95% CI 0.08 to 1.25) were noted. Alt-RAMEC/PFM exhibited a more favourable overjet correction when compared to RME/PFM, however, differences in other dental changes were insignificant. Conclusion: There is limited evidence with high risk of bias that Alt-RAMEC/PFM can result in a statistically significant increase in maxillary protraction compared with RME/PFM in Chinese subjects over the short-term. High-quality long-term RCTs with inclusion of patient-reported outcomes are required.