RETENTION AND POST EXPANSION STABILITY AFTER MARPE : A SYSTEMATIC REVIEW

Abstract

Background: Miniscrew-Assisted Rapid Palatal Expansion (MARPE) has emerged as an effective alternative to conventional rapid palatal expansion (RPE) and surgically assisted rapid palatal expansion (SARPE) for correcting transverse maxillary deficiencies in skeletally mature patients. Although numerous studies have reported favorable skeletal outcomes, evidence regarding long-term retention protocols and post-expansion stability remains limited. Objective: To systematically evaluate the available evidence on retention protocols and post-expansion stability following MARPE in adolescent and adult patients. Methods: A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines, with protocol registration in PROSPERO (CRD42025642633). Electronic searches were performed in MEDLINE (PubMed), Embase, Scopus, Web of Science, Cochrane Library, and Google Scholar. Studies involving patients aged ≥13 years treated with MARPE that reported retention protocols and/or post-expansion stability were included. Data regarding study characteristics, intervention details, retention methods, and stability outcomes were extracted. Risk of bias was assessed using the ROBINS-I tool. Results: Six observational studies met the inclusion criteria. Across the included studies, MARPE demonstrated favorable long term skeletal stability, with skeletal expansion being maintained more consistently than dentoalveolar expansion. Mild to moderate relapse was reported in all studies, with dental relapse consistently exceeding skeletal relapse. Periodontal changes, including slight reductions in buccal bone thickness and alveolar bone height, were generally minimal and clinically acceptable. Longer retention periods and appropriate retention protocols were associated with improved post-expansion stability. However, the overall quality of evidence was limited because most studies were retrospective and demonstrated moderate to serious risk of bias. Conclusion: Current evidence suggests that MARPE provides predictable and stable skeletal expansion with acceptable long-term outcomes in adolescents and adults. Although some dentoalveolar relapse is expected, skeletal relapse remains minimal when appropriate retention protocols are followed. Well-designed prospective randomized clinical trials with standardized retention protocols and longer follow-up periods are needed to strengthen the available evidence.