Objective: The aim of this study was to analyze the available evidence on external apical root resorption (EARR) due to orthodontic movement to identify clinical and molecular factors associated to this condition.
Methods: An umbrella review was conducted, encompassing systematic reviews and meta-analyses. Four databases—PubMed, ScienceDirect, Scopus, and Cochrane—were searched. The reviews were critically evaluated according to PRISMA and AMSTAR-2 guidelines. The study protocol was registered with PROSPERO (CRD42020198971).
Results: Totally, 124 papers were considered eligible for this investigation. Following title and abstract screening, 10 papers (4 systematic reviews and 6 meta-analyses) were included. The AMSTAR-2 guideline was applied, and the evaluation was conducted in accordance with PRISMA guidelines. Factors such as female gender, adulthood, conventional fixed orthodontic treatment, heavy, continuous and prolonged loads, intrusive movements and anterior superior teeth with abnormal roots increased the risk of developing this condition. At the molecular level, biomarkers such as IL-1β, IL-6, IL-4, and dentin phosphoprotein (DPP) were considered crucial for early diagnosis of external root resorption (ERR). Notably, the IL-1β (+3954) gene polymorphism was the most significant predictor of this condition in patients undergoing orthodontic treatment.
Conclusions: Clinical and molecular factors, which are influenced by individual characteristics, must be identified to assess the risk of developing EARR. Prolonged treatments should be avoided, and immunoassays to analyze proteins in gingival crevicular fluid (GCF) should be utilized for early diagnosis.