Antimicrobial photodynamic therapy with dendrosomal curcumin and blue laser against Porphyromonas gingivalis

Background: Periodontitis is a chronic inflammatory disease that leads to the loss of tooth-supporting structures. Porphyromonas gingivalis is one of the main pathogens responsible for periodontitis. Because of the limitations of antibiotic use, various alternative approaches have been developed. Antimicrobial photodynamic therapy uses photosensitizers and light to eliminate pathogens. Curcumin is a promising photosensitizer, but has low bioavailability and water solubility. However, dendrosomes can efficiently encapsulate curcumin, overcoming these obstacles. This study aimed to evaluate the efficacy of photodynamic therapy with blue laser and dendrosomal curcumin against Porphyromonas gingivalis. Methods: In this in vitro experiment, the minimum inhibitory concentration (MIC) of dendrosomal curcumin was determined using a serial dilution approach. Porphyromonas gingivalis suspensions were subjected to blue laser irradiation (447 nm, output power 100 mW) for 30 to 180 s. Finally, several subMIC dendrosomal curcumin concentrations and blue laser irradiation periods were applied to the bacterial suspensions. The negative control group received no therapy, whereas the positive control group was treated with 0.2% chlorhexidine. Consequently, the colony count of each group was calculated. Results: Treatment of Porphyromonas gingivalis with dendrosomal Curcumin at concentrations of 8-250 mu g/mL significantly reduced bacterial growth compared to untreated group. 90 second exposure to a blue laser (31.8 J/ cm2) completely inhibited the growth of Porphyromonas gingivalis. Blue laser irradiation for 60 s (21.2 J/cm2) markedly reduced bacterial growth but did not completely prevent its survival. Photodynamic therapy using dendrosomal curcumin at concentrations of 2-4 mu g/mL and irradiation for 30-90 s resulted in complete eradication of Porphyromonas gingivalis compared to controls (P < 0.05). Conclusion: The reduction in survival of Porphyromonas gingivalis following photodynamic therapy with dendrosomal curcumin and blue laser indicates that this technique could be a useful approach to eradicate Porphyromonas gingivalis infections.