Effects of photobiomodulation therapy on orthodontically induced inflammatory root resorption: a systematic review...

Orthodontically induced inflammatory root resorption (OIIRR) is a common complication of orthodontic treatment that may compromise tooth health and treatment outcomes. Photobiomodulation (PBM) therapy has emerged as a potential modality to mitigate against OIIRR. However, clinical studies have shown inconsistent efficacy and there is a lack of consensus on functional parameters, underscoring the need for evidence-based reviews.

Randomized controlled trials (RCTs) investigating PBM for OIIRR mitigation with quantitative root resorption assessment were included in the review. An electronic search was conducted across six databases (PubMed, Web of Science, Cochrane Library, Embase, MEDLINE, and Scopus) and the OPENGREY.EU for grey literature. References of included articles and relevant reviews were manually screened. The search was last updated on May 27th, 2025, with no publication date restrictions. The quality of included studies and evidence certainty of outcomes were assessed using the Cochrane Risk of Bias Tool 2.0 (RoB 2) and the 'Grading of Recommendations, Assessment, Development and Evaluations' (GRADE) framework. Following the heterogeneity evaluation, meta-analysis was performed on eligible studies using RevMan 5.3 software. Inter-rater agreement during study selection and quality assessment was quantified using Cohen's kappa statistics. The significance threshold was set at p < 0.05.

From a total of 893 records, 13 RCTs were included in the systematic review, with 4 selected for meta-analysis. Among all the included studies, only two demonstrated low risk of bias. Possible functional settings of PBM for OIIRR varied across studies (output power 100-200 mW, energy density 5-10 J/cm², and per-session dose 10-100 J/tooth). Within these ranges, appropriate cumulative doses and a tapered irradiation frequency protocol could influence PBM efficacy. The meta-analysis revealed that PBM was associated with a statistically significant (p < 0.01) but modest reduction (MD: -0.13 mm³, 95% CI: -0.17 to -0.09 mm³) in OIIRR of maxillary first premolars undergoing buccal tipping movement.

PBM shows potential in reducing OIIRR in the maxillary first premolar during buccal tipping, especially in the early stages of treatment. However, variability in PBM parameters and limited studies with low risk of bias indicate the need for standardized protocols and higher-quality research.