Three-dimensional evaluation of dentoalveolar and skeletal transverse changes between rapid maxillary expansion and slow maxillary expansion in growing subjects – A systematic review and meta-analysis

To systematically compare dentoalveolar and skeletal changes of RME and SME using same expanders with different activation protocols via 3D radiographs. Pubmed, Scopus, LILACS, Cochrane Library and Google Scholar were searched till April 2022. Randomized control trials (RCTs) were included. Statistical analysis performed with Tau2 test to evaluate heterogeneity in the included studies. Risk of bias (RoB) was evaluated using Cochrane RoB 2.0 tool. 5 RCTs were included. RoB revealed one study have low risk of bias and others have some concerns. Meta-analysis showed that both RME and SME displayed significant intermolar expansion (p>0.05) with RME showing significantly greater molar tipping. Random effects meta-analysis performed for maxillary intermolar distance at cuspal [SMD=0.23(95% CI=-0.50 to 0.95)] and alveolar level [SMD=0.76(95% CI=-0.57 to 2.09)] revealed no significant difference between groups with low reliability. RME showed significantly increased posterior skeletal nasal width [P value=0.007, SMD= 0.95(95% CI= 0.25 to 1.64)] with low heterogeneity (I2=24%) and good reliability. Greater molar tipping, determined using buccolingual inclination can be noted in RME. Increase in effective arch width and greater bodily translation was observed in SME. Utilizing the correct expansion protocol in the relevant clinical scenarios can prevent adverse periodontal complications during expansion and provide greater post-expansion stability.