Skeletal and dental effects of surgically assisted rapid palatal expansion: a systematic review of randomized controlled trials

BACKGROUND: Surgically assisted rapid maxillary expansion (SARME) is a surgical technique developed to correct transverse discrepancies in skeletally mature patients. However, there is limited evidence concerning the immediate skeletal and dental changes obtained only due to SARME. OBJECTIVE: The aim of the present systematic review is to investigate the immediate skeletal and dental effects of SARME in adult patients with transverse maxillary hypoplasia. SEARCH METHODS: An electronic search of the literature in MEDLINE, The Cochrane Library, Lilacs and Scopus databases was performed. SELECTION CRITERIA: Only randomized controlled trials (RCTs) studies investigating the skeletal and dental effects of SARME procedures in adult patients were included. DATA COLLECTION AND ANALYSIS: The included studies received a methodological quality scoring according to the revised Cochrane risk-of-bias tool for randomized trials. The quality of evidence was assessed by means of the Grading Recommendation Assessment, Development and Evaluation (GRADE) system. For each included study and for each analysed parameter, the difference in means and 95 per cent confidence interval was calculated between baseline and immediate post-expansion. A meta-analysis of original outcome data, if possible, was conducted. RESULTS: Nine articles were selected. The methodological quality ratings indicated that one study was at low risk of bias, seven presented some concerns and only one was at high risk of bias. In all the included studies, the SARME procedure resulted in a significant expansion of the maxillary transverse dimension. The meta-analysis compared skeletal and dental inter-molar width before and after treatment: the mean difference was of 3.3 mm (2.8-3.9) and 7.0 mm (6.1-7.8), respectively (P-value less than 0.001). The quality of evidence was low-moderate. CONCLUSIONS: SARME is effective in obtaining a significant expansion of the maxillary transverse dimension. However, the immediate SARME effect is mainly a molar expansion rather than a pure bone transverse widening of the maxilla. REGISTRATION: The review protocol was registered at PROSPERO database with the registration number CRD42018117967.