Comparison of orthodontic root resorption of root-filled and vital teeth: A meta-analysis

In this systematic review, the authors aimed to answer the following question: Do vital teeth differ in the level of external root resorption induced by means of orthodontic treatment compared with root-filled teeth?

The search strategy was performed in 6 electronic databases and in gray literature for articles published until July 29, 2021. Two reviewers independently assessed potentially eligible studies according to the following criteria: studies that evaluated patients undergoing fixed orthodontic therapy and compared the mean difference in millimeters of orthodontically induced external root resorption in endodontically treated teeth with the vital contralateral tooth. Only randomized, quasi-randomized, nonrandomized, cohort, case-control, or cross-sectional studies were considered eligible. There were no restrictions on language or publication time. Two reviewers also independently extracted data on the characteristics of the included studies, methods, and results, and performed risk-of-bias analysis using the Meta-Analysis of Statistics Assessment and Review instrument. Estimates of interest were calculated using random-effects meta-analyses. The certainty of the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation tool.

Eleven studies were included in the quantitative synthesis. Endodontically treated teeth had a lower level of root resorption (mean difference, 0.45 mm; 95% CI, -0.69 to -0.21 mm). However, the level of certainty of the evidence was considered very low owing to confounding factors.

Endodontically treated teeth may have a lower level of orthodontically induced root resorption than vital teeth, but the evidence is still uncertain about this outcome. Furthermore, owing to the small effect size, this difference might not be clinically significant (up to 1 mm).