Effects of Photodynamic Therapy with Blue Light and Curcumin as Mouth Rinse for Oral Disinfection: A Randomized Controlled Trial

Abstract

Objective: The purpose of this study was to evaluate the effects of the antimicrobial photodynamic therapy (a-PDT) with blue light and curcumin on oral disinfection during the 2 h after treatment. Background data: a-PDT is a technique that can potentially affect the viability of bacterial cells, with selective action targeting only areas with photosensitizer accumulation. Materials and methods: A randomized controlled trial was undertaken. Twenty-seven adults were randomly divided into three groups: (1) the PDT group, which was treated with the drug, curcumin, and blue light (n=9); (2) the light group, which was treated only with the blue light, and no drug (n=9) and; (3) the curcumin group, which was treated only with the drug, curcumin, and no light (n=9). The irradiation parameters were: blue light-emitting diode (LED) illumination (455 +/- 30 nm), 400 mW of average optical power, 5 min of application, illumination area of 0.6 cm(2), 600 mW/cm(2) of intensity, and 200 J/cm(2) of fluence. A curcumin concentration of 30 mg/L was used. The saliva samples were collected for bacterial counts at baseline and after the experimental phases (immediately after treatment, and 1 and 2 h after treatment). Serial dilutions were performed, and the resulting samples were cultured on blood agar plates in microaerophilic conditions. The number of colony-forming units (CFU) was determined. Results: The PDT group showed a significant reduction of CFU immediately after treatment (post-treatment) with PDT (5.71 +/- 0.48, p=0.001), and 1 h (5.14 +/- 0.92, p=0.001) and 2 h (5.35 +/- 0.76, p=0.001) after treatment, compared with pretreatment (6.61 +/- 0.82). There were no significant changes for the light group. The curcumin group showed a significant increase of CFU 1 h after treatment (6.77 +/- 0.40, p=0.02) compared with pretreatment (5.57 +/- 0.91) falling to baseline values at 2 h after treatment (5.58 +/- 0.70). Conclusions: The PDT group showed significant difference in microbial reduction (p<0.05) compared with both the light and curcumin groups until 2 h post-treatment. The new blue LED device for PDT using curcumin may be used for reduction of salivary microorganisms, leading to overall disinfection of the mouth (e.g., mucosa, tongue, and saliva), but new protocols should be explored.