Effects of physical adjunctive interventions on root resorption in accelerated orthodontic treatment: A systematic review and meta-analysis.

BACKGROUND

Orthodontically induced root resorption (RR) is a frequent adverse effect that may compromise long-term tooth stability. Physical adjunctive interventions (PAIs), such as vibration, photobiomodulation, low-intensity pulsed ultrasound (LIPUS), and low-intensity electrical stimulation (LIES), have been proposed to accelerate tooth movement while potentially minimizing RR, but their efficacy remains unclear.

OBJECTIVE

To systematically evaluate the effect of PAIs on RR during orthodontic treatment based on evidence from randomized controlled trials (RCTs).

MATERIALS AND

METHODS

Databases included PubMed, Scopus, Web of Science, Embase, and CENTRAL up to May 2025, supplemented by Google Scholar, TRIP, OpenGrey, PQDT Open, and hand-searching of orthodontic journals. No restrictions were applied on language or publication status. Eligibility included human randomized controlled trials comparing non-surgical physical adjunctive interventions with conventional orthodontic treatment and reporting quantitative orthodontically induced root resorption. Two reviewers independently performed screening, data extraction, and RoB 2 assessment; RR harms were evaluated with a modified McHarm tool, and certainty was appraised using the GRADE approach. Meta-analysis was conducted when appropriate. PROSPERO registration CRD420251116993.

RESULTS

Twenty-two RCTs (n=534) were included. Evidence certainty was low to very low. Vibration and LIES showed no significant effect. LIPUS reduced root length loss during canine retraction by 0.015mm/week (P=0.042) and premolar volume loss by 0.53mm3 (P<0.001). LED trays lowered premolar volume loss by 0.15mm3 (P<0.001). Laser therapy reduced RR scores during En-masse retraction (P<0.05). None of the PAIs increased RR compared with controls.

CONCLUSIONS

PAIs exhibit variable influence on RR. LIPUS and daily LED phototherapy show the most promising protective effects; however, current evidence remains limited by methodological weaknesses, small sample sizes, and short follow-up periods. Further well-designed RCTs are needed before widespread clinical adoption. PROSPERO (Registration ID: CRD420251116993).