title: Susceptibility of planktonic cultures of Streptococcus mutans to photodynamic therapy with a light-emitting diode.
abstract: The objective of this study was to evaluate the effect of photodynamic therapy with erythrosine and rose bengal using a light-emitting diode (LED) on planktonic cultures of S. mutans. Ten S. mutans strains, including nine clinical strains and one reference strain (ATCC 35688), were used. Suspensions containing 10⁶ cells/mL were prepared for each strain and were tested under different experimental conditions: a) LED irradiation in the presence of rose bengal as a photosensitizer (RB+L+); b) LED irradiation in the presence of erythrosine as a photosensitizer (E+L+); c) LED irradiation only (P-L+); d) treatment with rose bengal only (RB+L-); e) treatment with erythrosine only (E+L-); and f) no LED irradiation or photosensitizer treatment, which served as a control group (P-L-). After treatment, the strains were seeded onto BHI agar for determination of the number of colony-forming units (CFU/mL). The results were submitted to analysis of variance and the Tukey test (p ≤ 0.05). The number of CFU/mL was significantly lower in the groups submitted to photodynamic therapy (RB+L+ and E+L+) compared to control (P-L-), with a reduction of 6.86 log₁₀ in the RB+L+ group and of 5.16 log₁₀ in the E+L+ group. Photodynamic therapy with rose bengal and erythrosine exerted an antimicrobial effect on all S. mutans strains studied.
authors.affiliation: Department of Biosciences and Oral Diagnosis, Univ. Estadual Paulista, São José dos Campos, SP, Brazil. carol_biolog@yahoo.com.br
authors.forename: Anna Carolina Borges Pereira A
authors.initials: AC
authors.lastname: Costa
authors.forename: José
authors.initials: J
authors.lastname: Chibebe Junior
authors.forename: Cristiane Aparecida
authors.initials: CA
authors.lastname: Pereira
authors.forename: Ana Karina da Silva
authors.initials: AK
authors.lastname: Machado
authors.forename: Milton
authors.initials: M
authors.lastname: Beltrame Junior
authors.forename: Juliana Campos
authors.initials: JC
authors.lastname: Junqueira
authors.forename: Antonio Olavo Cardoso
authors.initials: AO
authors.lastname: Jorge
mesh_terms: D000704:Analysis of Variance; D058491:Bacterial Load; D018441:Biofilms / Q000187:drug effects / Q000528:radiation effects; D002478:Cells, Cultured; D003731:Dental Caries / Q000188:drug therapy*; D004923:Erythrosine / Q000494:pharmacology; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000494:pharmacology*; D012395:Rose Bengal / Q000494:pharmacology; D013295:Streptococcus mutans / Q000187:drug effects* / Q000302:isolation & purification / Q000528:radiation effects; D013997:Time Factors
chemical_list: D017319:Photosensitizing Agents; D012395:Rose Bengal; D004923:Erythrosine