Assessment of the periodontal health status and gingival recession during orthodontic treatment with clear aligners and fixed appliances: A systematic review and meta-analysis

Background: The aim was to assess periodontal health maintenance and gingival recessions development in pa-tients undergoing an orthodontic treatment with clear aligners (CA) and fixed appliances (FA).Material and Methods: An electronic search in MEDLINE, Scopus, The Cochrane Library, and Web of Science was performed up to September 2022 to identify all potential articles. Two investigators independently selected the studies according to the inclusion criteria. Prospective and retrospective studies assessing the periodontal health status and gingival recession development during the orthodontic treatment with buccal FA and CA were included. Case series, cross-sectional studies, and studies with less than two months of follow-up were excluded. Two investigators independently extracted the data from included articles and assessed risk of bias across studies using the Cochrane Collaboration tool. Qualitative and quantitative analyses of the data were performed. Pairwise meta-analysis using a random-effects model were used to compare periodontal indices between FA and CA treat-ment in different follow-up periods.Results: From the 129 potential studies, finally 12 studies were included. Only 8 could be included in the quantita-tive analysis. CA seems to slightly maintain better periodontal health indices. Only plaque index in a mid-term follow-up (mean difference (MD):-0.99; 95%; Confidence interval (CI) [-1.94 to-0.03]; P=.04; I2=99%), and pocket probing depth at a long-term follow-up (MD: -0.93mm; 95% CI [-1.16 to 0.7]; P<0.0001) reported statisti-cally significant results favoring CA.Conclusions: Up to the date there is not enough evidence to conclude that CA maintains better periodontal health during an orthodontic treatment than FA.