Orthodontically induced inflammatory root resorption in anterior teeth after treatment with clear aligners and fixed appliances, measured with cone-beam computed tomography: A systematic review and meta-analysis

Orthodontically induced inflammatory root resorption (OIIRR) is a common complication of orthodontic treatment. Clear aligners (CA) are thought to deliver lighter, intermittent forces than fixed appliances (FA), potentially reducing the extent of root resorption. However, comparative evidence remains limited, particularly from studies using cone-beam computed tomography (CBCT).This meta-analysis aimed to compare anterior tooth root resorption following treatment with CA vs. FA in patients with similar malocclusions, using CBCT-based linear measurements.A systematic search of MEDLINE/PubMed, Embase and the Cochrane Library was conducted in accordance with the PRISMA guidelines. Studies were eligible if they included patients older than 14 years with fully developed anterior roots and comparable malocclusion severity, and if they used CBCT to assess changes in the root length before and after treatment with either CA or FA. The random-effects meta-regression model was used to estimate the weighted mean difference (WMD) in root resorption. Subgroup analyses were performed according to tooth type and extraction status.Four high-quality cohort studies, comprising a total of 1,204 anterior teeth, met the inclusion criteria. Root resorption was significantly lower in the CA group than in the FA group (WMD: -0.47 mm; 95% CI: -0.55 to -0.40 vs. WMD: -0.54 mm; 95% CI: -0.75 to -0.33; p < 0.01). The difference was most pronounced in non-extraction cases involving the maxillary central incisors.Clear aligners are associated with significantly less anterior root resorption than FA in patients with comparable malocclusions. Although the absolute difference is modest, CA may represent a favorable treatment option for patients at increased risk of OIIRR.