Assessment of the effect of photodynamic therapy on the reduction of bacteria in deep dental caries lesions of primary teeth

Objective: The aim of this study was to evaluate the effect of photodynamic therapy on the reduction of bacteria in deep carious lesions of primary teeth. Materials and Methods: The study group consisted of 36 children with deep carious lesions in primary teeth. A LAD FotoSan®630 diode lamp was used for the therapy. Participants were randomly assigned to two groups: in the first group, antibacterial photodynamic therapy (aPDT) was performed using a 0.1% toluidine blue gel photosensitizer (FotoSan Agent® High, CMS Dental, Roslev, Denmark); in the second group, curcumin QroxB2® (CMS Dental, Roslev, Denmark) was used as the photosensitizer. Thirty-six carious lesions were selectively excavated. Dentin samples were collected twice—after caries removal and after aPDT application. Samples were cultured on Columbia Agar with sheep blood PLUS to assess microbial viability and the total number of microorganisms. Strain identification was performed using the VITEK® MS system (bioMérieux SSC, France). Diluted samples were then inoculated onto selective media: Mitis Salivarius Agar supplemented with sucrose for total streptococci, Mitis Salivarius Agar with bacitracin for Streptococcus mutans , Rogosa SL Agar for Lactobacilli , and Sabouraud Dextrose Agar for fungi. Results: A statistically significant reduction in the total number of microorganisms was noted after therapy. A decrease in bacterial counts was also observed on selective media for total Streptococci and Streptococcus mutans . The degree of microbial reduction did not significantly differ depending on the photosensitizer used. Follow-up examinations were performed at 3, 6, and 12 months. No pain symptoms or signs of treatment failure were observed. Conclusions: Photodynamic therapy appears to be highly effective in reducing bacteria in deep carious lesions of primary teeth. Clinical Significance: Photodynamic therapy may be successfully used as an adjunct in selective caries excavation.