Skeletal Effects of Slow Maxillary Expansion in Mixed Dentition Stage: A Systematic Review and Meta‐Analysis

Objectives Many cases of maxillary arch expansion require skeletal improvement of varying degrees. Therefore, the current systematic review and meta‐analysis aim to evaluate the effectiveness of the most widespread slow maxillary expansion (SME) in achieving the necessary skeletal changes during the mixed dentition stage in addition to dentoalveolar ones. Material and Methods An electronic search of five databases (PubMed, Scopus, Embase, Cochrane Library, and Google Scholar) was followed by manual searches in several journals. Both randomized controlled trials (RCTs) and nonrandomized studies were included, while case reports were excluded. Risk of bias was assessed using the Revised Version of Cochrane Risk‐Of‐Bias (ROB 2.0) tool for randomized studies (high, low, or some concerns) for individual elements from five domains (selection, intervention, missing data, outcome measurement, and reporting) and the ROBINS‐I tool for nonrandomized studies. The certainty of the evidence was evaluated according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Results In total, 108 full texts from 1427 identified articles were screened; 28 studies were included in this review (7 RCTs and 21 non‐RCTs), and 11 were appropriate for quantitative synthesis studies. Outcomes assessed dental and skeletal changes, such as inter‐molar/inter‐canine widths, as well as maxillary width. The study showed different changes related to the expansion device. Whereas, the meta‐analysis revealed that a greater increase in the inter‐molar width was found in the quad–helix (QH) group than in the removable plate (RP) group, and the difference was statistically significant, while the difference was not significant in inter‐canine width. Also, the increase in maxillary width was significant by using QH and RP. Thus, the QH was more effective than the expansion plate. Conclusions It can be concluded that SME during the mixed dentition can lead to different amounts of skeletal changes in addition to the dentoalveolar changes, and this amount is related to the expansion appliance used. The main limitation is that few studies have measured changes in maxillary width.