Avaliação do gel de papaína e azul de metileno na aplicação da terapia fotodinâmica – estudos “in vitro

Abstract

The concepts of minimal intervention have been increasingly discussed for conservative treatment of carious lesions. The papain-gel (Papacárie®) used for the chemical-mechanical removal of carious tissue and methylene blue used to perform photodynamic therapy, both are included in this concept. As new alternative treatment for caries lesions, the present study aims to evaluate the effects of papain gel with methylene blue (PapaMBlue®) for inactivation of S. mutans biofilm. The methodology compared the (PapaMBlue®) with methylene blue pure for ROS was used, also the cytotoxicity, subcellular location with confocal microscopy was applied. For the purposes of aPDT was applied red light on planktonic cells (S. mutans biofilm grown), also CFU analysis and confocal microscopy, as well transmission electron microscopy and hematoxylin and eosin stain (H&E) was analyzed. The (PapaMBlue®) produced safe amounts of ROS compared to pure methylene blue. Was observed the antimicrobial effect on S. mutans biofilm with (PapaMBlue®) were similar with MB (reduced 1-log CFU, dark), and reduction of CFU 2-logs on aPDT), almost equal to the control with chlorhexidine (reduction of 2.8-logs) serial dilution and CFU was used. For cytotoxicity both assays MTT and (PrestoBlue®) showed higher cell viability of fibroblasts treated with (PapaMBlue®) and methylene blue, possibly due to stimulation of mitochondrial activity. The fibroblasts treated with (PapaMBlue®) or methylene blue pure did not shows cytotoxic effects. The (PapaMBlue®) shows photoinactivation effect on S. mutans biofilm without affecting the integrity of fibroblasts, what could have future indication for clinical applications for treatment of deep caries, which will allow the simultaneous removal of the infected dentin with low level laser, preserving the healthy structures such the affected dentin and pulp.