Adjunctive effects of photodynamic therapy using indocyanine green in residual pockets during periodontal maintenance therapy: A split-mouth randomized controlled trial

Prospective studies have reported conflicting results regarding the adjunctive effect of antimicrobial photodynamic therapy (aPDT) on clinical and microbiological parameters in individuals under periodontal maintenance therapy (PMT). This study aimed to evaluate the clinical and microbiological adjunctive effects of aPDT using indocyanine green (ICG) in residual sites with probing depth (PD) ≥5 mm during PMT in comparison with scaling and root planing (SRP) alone.

A split-mouth randomized controlled clinical trial was conducted with 24 individuals in a PMT program. Contralateral quadrants with eligible residual sites were randomly assigned to either SRP + aPDT (test group) or SRP alone (control). aPDT included ICG dye and diode laser (909 nm) performed together with SRP and repeated 15 days after. Periodontal clinical parameters, periodontal inflamed surface area (PISA) index, and subgingival biofilm samples were collected at baseline (T1), 3 (T2), and 6 months later (T3). Microbiological analyses were performed by quantitative real-time polymerase chain reaction.

Significant improvements were observed in all clinical and microbiological parameters in both groups from T1 to T3. However, no significant differences were observed regarding plaque index, PD, and clinical attachment level. Test group showed significantly greater reductions in bleeding on probing (BOP), PISA index, and Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans levels, when compared with controls.

Both treatments resulted in significant clinical periodontal improvements, but with no significant differences between groups except from inflammation parameters. aPDT using ICG resulted in significant reductions in BOP and PISA index, as well as in P. gingivalis and A. actinomycetemcomitans levels.