IADR Abstract Archives
Clinical effectiveness of photodynamic therapy on the disinfection of dentures
Objectives: This study evaluated the effectiveness of photodynamic therapy (PDT) on the disinfection of complete dentures. Methods: Biofilm samples were collected from dentures of 30 patients, which were divided into two experimental groups (n=15/gp): Group 1- patients had their maxillary denture sprayed with 50mg/L of Photogem®; Group 2- patients had their maxillary denture sprayed with 100mg/L of Photogem®. After 30min of pre-irradiation, all dentures were exposure to blue LED light at 37.5J/cm2 (26min). Denture samples were taken with sterile cotton swab, before (left side surfaces) and after (right side surfaces) PDT. All microbial material was diluted (10-1 to 10-3) and plated (25μL) on selective media for Candida spp. (CHROMagar), Staphylococcus spp. (Manitol Salt Agar), mutans streptococci (SB20) and a non-selective media (Mueller Hinton). After incubation (48h/37ºC), the number of colony-forming units (cfu/mL) was counted. Microorganisms which grew on selective media were identified using biochemical methods before and after PDT. The data were submitted to Kruskal-Wallis and Dunn tests (p<.05). Results: PDT with 100mg/L (Group 2) sterilized 60% of dentures. In addition, the disinfected dentures showed reduced cfu/mL values of Candida spp. (p=0.0035), Staphylococcus spp. (p=0.0214), mutans streptococci (p=0.0003) and non-identified species (p<0.0001) compared to cfu/mL observed before PDT. For Group 2, the identified species were Candida albicans, Candida glabrata, Candida tropicalis, Staphylococcus aureus and Streptococcus mutans. In Group 1, the results showed that 40% of dentures were sterilized with 50mg/L. PDT also promoted significant reduction in cfu/mL of Candida spp. (p=0.0003), Staphylococcus spp. (p=0.0075), mutans streptococci (p=0.0012) and non-identified species (p<0.0001) compared to cfu/mL obtained before PDT. For Group 1, the colonies grown after PDT were identified as Candida albicans, Staphylococcus aureus and Streptococcus mutans. Conclusions: PDT demonstrated to be an alternative procedure to disinfect dentures from patients. The use of 100mg/L was more effective in sterilizing dentures.
Grant: FAPESP2005/02192-8