Evaluation of possible risk factors for external apical root resorption after orthodontic treatment

Abstract

Objective: this study aimed to review the research related to possible risk factors of external apical root resorption (EARR), associated with orthodontic treatment. Material and Methods: the MEDLINE database was explored, via PubMed, using the advanced search option. The keywords selected from the Medical Subject Headings (MeSH), used in combination with “AND” and “OR,” were: orthodontics, root resorption, incisor, and genetic polymorphism. The research found articles from 1993 to 2016. Results: it was found that the orthodontic treatment can be considered as a risk factor of EARR, mostly affecting the upper incisors. Sex and chronological age, along with other clinical factors and those related to orthodontic treatment, do not seem to influence the degree of EARR, except the prolonged treatment time and heavy forces that are associated with increased amounts of EARR. Studies evaluating treatment with extractions, intermaxillary elastics, and different genetic polymorphisms showed contradictory results, restricting the determination of whether these factors can contribute to EARR. Methodological and population sample differences among the evaluated articles may explain the divergent results found in the literature. Conclusion: although various intrinsic, clinical, orthodontic, and genetic factors were described in the literature, the most common factors associated with increased values of EARR were prolonged treatment time and heavy forces during the orthodontic treatment.