Terapia fotodinÃmica antimicrobiana aplicada em espÃcimes de resina acrÃlica confeccionados em diferentes laboratÃrios de prÃtese dentÃria

This study evaluated the effect of photodynamic therapy on acrylic resin specimens made in different dental prosthetic laboratories. Six laboratories (L), registered in the Regional Council of Dentistry of CearÃ, were randomly selected and were not identified to the operator of the experiments. The therapy used erythrosine 22 ÂM as photosensitizer (P) associated with irradiation with LED of 520 nm, at 38 J/cm2 (L). Fifty specimens of each laboratory were divided into 5 groups (n: 10): sterile positive control in Ethylene Oxide (EO); negative control (P-L-), untreated; control (P+L-) only stained with erythrosine; control (P-L+) only irradiated with 520 nm LED; experimental (P+L+). The specimens were placed in individual tubes containing saline solution and the obtained suspension was diluted and plated on Blood Agar, Sabouraud Dextrose and CHROMagar OrientationÂ, for incubation within 48 hours at 37ÂC. The number of colony- forming-units of viable bacteria and yeasts was obtained. The statistical tests of Kruskal-Wallis and Dunn were carried out, which showed a significant difference between the groups (P-L-) and (P+L+) (p <0.0001), identifying contamination with different microorganisms in the six laboratories, such as Enterococcus spp, Pseudomonas spp, Staphylococcus aureus, Klebsiella, Escherichia coli and Staphylococcus saprophyticus. Viable bacteria were eliminated by 100% in laboratories L1, L2, L4 and L5. In laboratories L3 and L6 elimination of viable bacteria was 99%. The viable yeasts were completely eliminated after PDT for laboratories L1, L2, L4 and L5. In the laboratory L3, viable yeast count was reduced by 97% after PDT, whereas in the L6, the reduction was 94%. It was concluded that PDT was effective in microbial removal from the surfaces of the acrylic resin specimens.InfecÃÃo cruzada entre consultÃrio odontolÃgico e laboratÃrio de prÃtese pode ocorrer quando procedimentos de biosseguranÃa nÃo sÃo executados adequadamente. A desinfecÃÃo dos trabalhos protÃticos à uma etapa importante para prevenir a contaminaÃÃo cruzada entre pacientes, dentistas e tÃcnicos de laboratÃrio. Este estudo avaliou a eficÃcia da terapia fotodinÃmica (TFD) sobre espÃcimes de resina acrÃlica confeccionados em seis diferentes laboratÃrios de prÃtese dentÃria. Os laboratÃrios, cadastrados no Conselho Regional de Odontologia do CearÃ, foram selecionados por sorteio e nÃo foram identificados ao operador dos experimentos. A terapia teve como fotossensibilizador a eritrosina 22 ÂM (P), associada à irradiaÃÃo com LED de 520 nm, a 38 J/cm2 (L). Cinquenta espÃcimes de cada laboratÃrio foram distribuÃdos em 5 grupos (n:10): controle positivo (padrÃo ouro), estÃril em Ãxido de etileno (EO); controle negativo (P-L-), sem tratamento; controle (P+L-) apenas corado com eritrosina; controle (P-L+) apenas irradiado com LED 520 nm; experimental (P+L+). Os espÃcimes foram colocados em tubos individuais contendo soluÃÃo salina e agitados para desprendimento microbiano. A suspensÃo obtida foi diluÃda e plaqueada em Ãgar Sangue, Sabouraud Dextrose e CHROMagar OrientationÂ, para incubaÃÃo em 48 horas a 37ÂC. O nÃmero de unidades formadoras de colÃnias (UFC) bacterianas e fÃngicas viÃveis foi obtido, para comparaÃÃes entre os grupos. Foram realizados os testes estatÃsticos de Kruskal-Wallis e Dunn, que determinaram diferenÃa significante entre os grupos (P-L-) e (P+L+) (p