Comparison of external apical root resorption in orthodontic patients treated with clear aligners, self-ligating with conventional fixed appliance therapy: a CBCT-based systematic review and meta-analysis

Objective To compare the extent of external apical root resorption (EARR) in orthodontic patients treated with clear aligners and self-ligating with conventional fixed appliance, using cone-beam computed tomography (CBCT).Materials and methods A systematic search was conducted in the CENTRAL, Cochrane Database of Systematic Reviews, Scopus, EMBASE and PubMed and Google Scholar along with a manual search of relevant journals. Prospective studies and randomized controlled trials evaluating EARR in patients treated with clear aligners, self-ligating and/or conventional fixed appliances were included. Risk of bias was assessed using RoB 2 and ROBINS-I tools. Meta-analysis was performed using random effects model, and certainty of evidence was assessed using GRADE.Results Ten studies met the inclusion criteria, of which six were included in quantitative synthesis comparing self-ligating and conventional appliances. Meta-analysis demonstrated no statistically significant difference in EARR between self-ligating and conventional appliances across maxillary and mandibular incisors [SMD = 0.07 mm; 95% CI: −0.19 to 0.34; I2 = 0%]. Qualitative synthesis indicated comparable EARR on CBCT across clear aligners, self-ligating and conventional appliances, with overall EARR remaining below clinically relevant thresholds and moderate certainty of evidence due to bias and heterogeneity.Conclusion CBCT-based evidence suggests that clear aligners, self-ligating and conventional brackets are all associated with measurable but clinically acceptable EARR, and appliance type does not appear to be a determining factor for its extent.