Microbiological Impact of Antimicrobial Photodynamic Therapy in Non-Surgical Periodontal Treatment

Periodontitis is one of the most common inflammatory diseases and it is linked to the presence of a dysbiotic subgingival microbiome. The purpose of this review is to evaluate the impact of antimicrobial photodynamic therapy (aPDT) on the subgingival microbiome. Herein, based on an extensive evaluation of randomized controlled trials (RCTs), the effects of aPDT as a supplement to non-surgical periodontal therapy (NSPT) were found to be the main focus of these works. Studies that focused on analyzing microbiological results were selected, yielding contradictory results. The observed microbiological changes were variable, even though some studies showed notable improvements in clinical indicators such as bleeding on probing (BOP), clinical attachment level (CAL), and probing depth (PD). Several studies found that aPDT did not significantly reduce important periodontal pathogens such Tannerella forsythia, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans. Nevertheless, after multiple aPDT sessions, other studies reported positive changes in the subgingival microbiome, with a rise in beneficial bacteria and a decrease in periodontopathogens. While aPDT seems to be a safe and well-tolerated adjuvant to non-surgical periodontal therapy, there is still conflicting evidence regarding how well it modulates the subgingival microbiota. Additional long-term research with larger sample sizes is required to evaluate the microbiological and clinical advantages of aPDT.