Inativação fotodinâmica em biofilme de Streptococcus mutans sobre bráquetes metálicos e cerâmicos: um estudo in vitro
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2016-02-16
Autores
Esper, Maria Ângela Lacerda Rangel [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O trabalho in vitro avaliou a eficácia da inativação fotodinâmica (PDI) da eritrosina (E) e hematoporfirina IX (H), com 10 µM, utilizando LED azul, dose de 75 J/cm2 em células planctônicas e biofilme de S. mutans (UA 159). Suspensões padrões contendo 107 células/mL foram preparadas e submetidas a diferentes condições experimentais: a) hematoporfirina IX e LED (H+L+); b) eritrosina e LED (E+L+); c) apenas LED (F-L+); d) tratamento somente com hematoporfirina IX (H+L-); e) somente com eritrosina (E+L-); e f) grupo controle, sem tratamento com fotossensibilizador (F) e sem a utilização de LED (F-L-). As cepas foram semeadas em ágar MSBS para contagem de unidades formadoras de colônias (UFC/mL). Na segunda parte do trabalho foi realizado a PDI em biofilme de S. mutans sobre bráquetes metálicos e cerâmicos, com H a 10 µM e LED azul. Os resultados foram submetidos à análise de variância e teste de Tukey (p<0,05) e demonstraram que a E sob efeito do LED (E+L+) não foi eficaz na PDI de células planctônicas, nos parâmetros usados (p=0,3644). No entanto, a H promoveu redução de 6,78 log10 (p<0,0001), no grupo de tratamento (H+L+). A PDI com a associação da H e LED foi efetiva na redução de 100% de culturas planctônicas de S. mutans, porém o mesmo não foi observado na associação com a E, na dosimetria utilizada no experimento. A PDI no biofilme de S. mutans sobre bráquetes metálicos, com a H e LED não foi eficaz nos parâmetros utilizados (p=0,1023), no entanto, ocorreu diminuição significativa de 53% sobre bráquetes cerâmicos (p=0,004). A H IX modificada é promissora como agente fotossensibilizador a ser empregado na técnica de PDI em associação ao LED azul, sendo necessários outros ensaios, em novas concentrações e/ou dosimetrias para se conseguir a inativação bacteriana.
The in vitro study evaluated the efficacy of photodynamic inactivation (PDI) with erythrosine (E) and hematoporphyrin (H) 10 µM, using a blue light-emitting diode (LED), a fluence of 75 J/cm2 , on planktonic cultures and biofilm of S. mutans (UA 159). Suspensions containing 107 cells/mL were prepared and were tested under different experimental conditions: a) hematoporphyrin IX and LED (H+L+); b) erythrosine and LED irradiation (E+L+); c) only LED (P-L+); d) only hematoporphyrin IX (H+L-); e) only erythrosine (E+L-); and f) control group, no LED irradiation or photosensitizer (P) treatment (P-L-). After treatment, the strains were seeded onto MSBS agar in order to determine the number of colony-forming units (CFU/mL). The second part of this work consisted of the PDI of S. mutans biofilm on metal and ceramic brackets with the H 10 μM and blue LED. The results were submitted to analysis of variance and the Tukey test (p<0.05) and showed that E under the effect of LED proved to be ineffective in the PDI of planktonic cultures with the parameters used (p=0.3644). H, however, caused a reduction of 6.78 log10 (p<0.0001) in the treatment group (H+L+). PDI with H and LED exerted antimicrobial effect of 100% of the S. mutans strain studied, whereas the same was not observed in the association with E in the dosimetry used in this work. PDI on S. mutans biofilm on metal brackets, with H and LED was not effective with the parameters used (p=0.1023), however on ceramic brackets caused a significant reduction of 53% (p=0,004). Modified H IX is a promising photosensitizer to be used in the PDI technique in combination with blue LED. Therefore, new tests with new concentrations and/or dosimetry are needed to achieve bacterial inactivation.
The in vitro study evaluated the efficacy of photodynamic inactivation (PDI) with erythrosine (E) and hematoporphyrin (H) 10 µM, using a blue light-emitting diode (LED), a fluence of 75 J/cm2 , on planktonic cultures and biofilm of S. mutans (UA 159). Suspensions containing 107 cells/mL were prepared and were tested under different experimental conditions: a) hematoporphyrin IX and LED (H+L+); b) erythrosine and LED irradiation (E+L+); c) only LED (P-L+); d) only hematoporphyrin IX (H+L-); e) only erythrosine (E+L-); and f) control group, no LED irradiation or photosensitizer (P) treatment (P-L-). After treatment, the strains were seeded onto MSBS agar in order to determine the number of colony-forming units (CFU/mL). The second part of this work consisted of the PDI of S. mutans biofilm on metal and ceramic brackets with the H 10 μM and blue LED. The results were submitted to analysis of variance and the Tukey test (p<0.05) and showed that E under the effect of LED proved to be ineffective in the PDI of planktonic cultures with the parameters used (p=0.3644). H, however, caused a reduction of 6.78 log10 (p<0.0001) in the treatment group (H+L+). PDI with H and LED exerted antimicrobial effect of 100% of the S. mutans strain studied, whereas the same was not observed in the association with E in the dosimetry used in this work. PDI on S. mutans biofilm on metal brackets, with H and LED was not effective with the parameters used (p=0.1023), however on ceramic brackets caused a significant reduction of 53% (p=0,004). Modified H IX is a promising photosensitizer to be used in the PDI technique in combination with blue LED. Therefore, new tests with new concentrations and/or dosimetry are needed to achieve bacterial inactivation.
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Ortodontia, Lesão de mancha branca, S. mutans, Cárie dentária, Inativação Fotodinâmica, PDT, Eritrosina, Hematoporfirina IX, Biofilme, Ortodontics, White spot lesion, S. mutans, Dental caries, Photodynamic inactivation, PDT, Erythrosine, Hematoporphyrin IX, LED, In vitro