The influence of photodynamic therapy on the supragingival plaque accumulation and bacterial composition in orthodontic patients: a randomized controlled trial.

Summary

In a registered, single-blind, four-arm RCT (n=48; 40 analyzed), toluidine blue-based 660 nm photodynamic therapy reduced plaque indices comparably to chlorhexidine and fluoride varnish and lowered total supragingival bacterial counts. No new white spot lesions occurred in PDT or CHX groups, and no harms were reported over 18 weeks.

Key Findings

• PDT and chlorhexidine groups had significantly lower plaque indices than control at 12 and 18 weeks.
• Total supragingival bacterial counts decreased significantly in PDT, chlorhexidine, and TCP-5% NaF groups over time.
• No new white spot lesions were observed in PDT or chlorhexidine groups; no harms were reported.

Clinical Implications

Clinicians may consider protocolized PDT (toluidine blue plus 660 nm laser at bonding and 6–12 week intervals) to reduce plaque and gingival inflammation and help prevent white spot lesions without chlorhexidine-associated staining or taste disturbance.

Limitations

• Single-center study with modest sample size (40 analyzed)
• Short follow-up (18 weeks) and no significant effect on subgingival bacterial composition

Future Directions

Conduct multicenter, double-blind RCTs with longer follow-up to assess caries incidence, optimize PDT parameters and intervals, evaluate patient-reported outcomes, and perform cost-effectiveness analyses.