Curcumin as Photosensitizing Agent for 445nm Laser Irradiation

Objectives: The primary goal of periodontitis therapy is the removal of supra- and subgingival biofilm. Therefore, elimination of pathogenic bacteria is limited by morphological conditions of the root surface. The aim of the present study is to show germ-reducing efficacy of different laser-based photochemical systems, especially a novel curcumin-based therapy option.
Methods: Seventy-seven titanium bars were inoculated with an artificial biofilm consisting of common periopathogenic bacteria and inserted into an artificial periodontal pocket model. Following groups (n = 11) were used: (I) laser irradiation (445nm, 0,6W, 25% duty cycle,100Hz, 10s) (SLB) (SiroLaser Blue, Sirona Dentsply, Bensheim, Germany), (II) antimicrobial photodynamic therapy (aPDT) (Helbo, Bredent, Walldorf, Germany), (III) antimicrobial photothermic therapy (aPTT) (EmunDo, A.R.C. Laser, Nuernberg, Germany), (IV) dimethylsulfoxid-solution (DMSO), (V) curcumin-solution (C), (VI) curcumin-solution with laser irradiation (SLB 445nm, 0,6mW, 25% duty cycle, 100Hz, 10s) (C+L), (VII) untreated control. Subsequently, samples were restored in Eppendorf tubes and analyzed microbiologically by a quantitative real-time PCR. The main parameter for the analysis of group differences was the total bacterial load (TBL). Statistical analysis was performed with non-parametric methods (Wilcoxon, Mann-Whitney).
Results: Statistically significant bacterial reduction could be observed within all groups (p<0.05). Percental reduction was as follows: (SLB) 95.03% (min: 94.29%, max: 99.51%), (aPDT) 83.91% (min: 44.46%, max: 99.79%), (aPTT) 99.63% (min: 97.09%, max: 99.74%), (DMSO) 95.69% (min: 96.39%, max: 98.12%), (C) 97.35% (min: 96.54%, max: 96.85%) and (C+L) 97.15% (min: 96.29%, max: 99.48%). No statistically significant difference in bacteria reduction could be observed for single laser irradiation (SLB), DMSO-solution (DMSO) and curcumin-solution with (C+L) or without additional laser irradiation (C).
Conclusions: Highest antibacterial efficacy could be observed for samples treated with aPTT. Employing curcumin as photosensitizing agent for 445nm laser irradiation did not result in an improved antibacterial effect compared to laser application alone.