Avaliação do efeito fotodinâmico do azul de metileno veiculado em meio surfactante como terapia adjuvante ao tratamento periodontal – ensaio clínico, aleatorizado, controlado, duplo- cego

Abstract

Periodontal disease is an inflammation that affects the supporting tissues of the teeth in response to the presence of microorganisms. Antimicrobial photodynamic therapy aims at the production of reactive oxygen species and is used as an adjunct therapy for the elimination of microorganisms. This phototoxic effect requires photosensitizer – methylene blue in this case -, light irradiation of adequate wavelength and oxygen. The molecules of methylene blue in water can become dimers reducing the effect of therapy. Sodium dodecyl sulfate controls this aggregation. Thus, this study evaluated the photodynamic effect of 0.003% - 100µM methylene blue delivered in 0.25% sodium dodecyl sulfate in chronic periodontitis. For this, thirty six participants were included that were treated with scaling and root planning, randomly allocated in four groups: 1) treated with photodynamic therapy and methylene blue conveyed in sodium dodecyl sulfate (n=9); or 2) with photodynamic therapy and methylene blue in water (n=10); 3) with methylene blue in water without light irradiation (n=9), or 4) treated with photosensitizer in sodium dodecyl sulfate without light irradiation (n=8). The pre- irradiation time was 1min and the irradiation time was 2min, single application. Laser (Therapy EC, DMC, São Carlos, Brazil) with wavelength of 660nm and 100mW of power was used. Quantitative microbiological evaluation was realized by counting colony-forming units from cultivated subgingival biofilm samples, in anaerobiosis, before and after irradiation procedures. This microbial count was the primary outcome and clinical probing depth was the secondary one. There was no significant difference between the groups in both bacterial reduction and the clinical parameter evaluated. It was concluded that the phototoxic effect of methylene blue in sodium dodecyl sulfate in the adjuvant treatment of periodontitis was not enough to reduce the amount of bacteria in biofilm or the pocket probing depth.