A comparison of alternate-rapid maxillary expansion and constriction protocol with conventional rapid maxillary expansion in class III malocclusion patients – A systematic review and meta-analysis

Class III malocclusion is a challenging orthodontic condition that can cause functional, esthetic, and psychosocial problems if untreated. Two common protocols – Alternate-Rapid maxillary expansion and constriction (AltRAMEC) and conventional rapid maxillary expansion (RME) – are used to manage it. However, their comparative effectiveness remains debated. The objective of the study is to compare the effectiveness of Alt-RAMEC versus conventional RME in treating Class III malocclusion with a focus on skeletal, dentoalveolar, and soft tissue outcomes. Included studies were randomized controlled trials and cohort studies comparing Alt-RAMEC and conventional RME in English. Excluded studies were without direct comparisons, those in other languages, or with insufficient outcome data. Systematic searches were conducted in PubMed/MEDLINE, Cochrane Library, and DOAJ up to January 2025. Data on study design, sample size, outcome measures, and risk of bias were extracted. Meta-analysis was performed using standard statistical techniques. Eleven studies were included. Alt-RAMEC significantly improved overjet (mean difference = 0.57 [0.18, 0.96]) versus conventional RME. No statistically significant differences were observed for other cephalometric and skeletal outcomes (e.g., Sella-Nasion-A, SellaNasion-B, ANB, Condyle to A, Wits appraisal). Alt-RAMEC may offer better dentoalveolar outcomes (notably overjet correction) than conventional RME, though skeletal and soft tissue changes were comparable. Long-term, high-quality studies are needed to confirm these findings. Registration PROSPERO (CRD42023456789).