External Root Resorption In Orthodontic Treatment With Different Types Of Rapid Maxillary Expansion(RME): A Systematic Review And Meta-analysis

Objective: As rapidly opening the middle palatal suture to expand the transverse width of the maxilla,RME has the risk of leading to root resorption.The purpose of this study was to systematically evaluate the external root resorption in participants receiving RME and to compare external root resorption in participants treated with different types of RME.Methods: A systematic search of eight electronic databases were conducted through 11 December,2019.Additionally,manual searches of reference lists of relevant articles were completed to identify additional publications not identified by electronic searches.The lowest levels of evidence accepted for inclusion were before-and-after study.Specific inclusion and exclusion criteria were used.Data extraction and analysis were conducted by two investigators independently.The quality of studies was assessed by Cochrane collaboration's tool for assessing of bias or methodological index for non-randomized studies.The original outcome underwent statistical pooling by Review Manager 5.3.Results: A total of 656 original articles were identified from the electronic database.A total of 8 studies were included for qualitative analysis,and 7 of them were statistically pooled in meta-analysis.The results of meta-analysis were as follows:1.The external root resorption in treatment with tooth-borne RME at the end of the active expansion phase was 1.00mm(MD = 1.00 mm,95% CI [0.41,1.60],P<0.00001).2.The external root resorption in treatment with tooth-borne RME after the retention period was 0.38mm(MD = 0.38 mm,95% CI [0.26,0.51],P<0.00001).3.The external root resorption in treatment with bone-borne RME was 0.28mm(MD = 0.28 mm,95% CI [0.03,0.52],P = 0.03).4.No significant differences were observed in external root resorption between tooth-tissue-borne RME group and tooth-borne RME group(SMD =-0.23,95% CI [-0.47,0.02],P=0.08).5.The external root resorption in treatment with bone-borne RME was significantly lower than that with tooth-borne RME(MD =-0.08 mm,95% CI [-0.12,-0.04],P<0.0001).Conclusion: Current evidences suggest that significant external root resorption might occur after receiving all kinds of RME.Compared with tooth-borne RME,tooth-tissue-borne RME could not significantly reduce external root resorption,while bone-borne RME might have more advantages in causing less root resorption.However,due to the limited number of existing studies and problems in conducting or reporting,it is not possible to draw clear conclusions.