Antimicrobial Photodynamic Therapy as a Technique for Decontamination of Acrylic Resin Devices Provided by Different Dental Laboratories

[摘要] Introduction: Dentures, occlusal splints, surgical guides and orthodontic appliances are examplesof acrylic resin devices made in dental laboratories, which must be disinfected and even sterilizedbefore insertion into the oral cavity. This study evaluated the antimicrobial effect of photodynamictherapy (PDT) applied to acrylic resin specimens received from different laboratories.Methods: Three hundred standardized specimens were ordered from six randomly selectedlaboratories registered in the Council of Dentistry of Ceará (n=50). The PDT consisted in theassociation of 22 µM erythrosine, as a photosensitizer (P), and a 520-nm LED at 38 J/cm2 (L). Thespecimens of each laboratory were randomly distributed into five groups: positive control, sterilizedwith ethylene oxide; negative control, untreated (P-L-); erythrosine control, only stained (P+L-);LED control, only irradiated (P-L+); PDT (P+L+). Then, the specimens were individually sonicatedin saline solution; the suspension was diluted, plated on culture mediums (blood agar, sabourauddextrose agar and a non-selective chromogenic agar), and incubated for 48 hours at 37°C. Colonyforming-unit (CFU) counts were done and statistical tests of Kruskal-Wallis/Dunn were carried out.Results: The specimens from all laboratories were contaminated with bacteria and yeasts.Staphylococcus aureus, Staphylococcus saprophyticus, Escherichia coli, Enterococcus spp.,Klebsiella and Pseudomonas spp. were identified. The PDT significantly reduced CFU counts(P<0.0001), compared to P-L-.Conclusion: PDT was able to effectively decontaminate the acrylic resin specimens provided fromdental laboratories.

[学科分类] 基础医学

[关键词] Acrylic resins;Photochemotherapy;Contamination;Disinfection;Sterilization.