Terapia fotodinâmica antimicrobiana para Candida albicans: estudo microbiológico, biomolécula e de seus efeitos na resina acrílica

Abstract

The broad spectrum of oral candidiasis and their importance in clinical infection boosted researches intended to clarify the pathogenic mechanisms and identify selective treatments against Candida albicans. This study was divided into four chapters, with the following objectives: Chapter 1) Compare different types of antimicrobial photodynamic therapy (PACT) associations, through determination of Minimum Inhibitory Concentration (MIC), Minimum Fungicide Concentration (MFC), action front planktonic culture and biofilm of Candida albicans, on the associations: LED 630 nm/1 W/152 J cm-2, associated with methylene blue (MB) and toluidine blue ortho (TBO) and LED 520 nm/400 mW/152 J cm-2 with Bengal Rose (BR); Chapter 2) To evaluate possible damage to the surface structure of acrylic resins, such as color change, surface roughness and mass loss, through the use of photosensitizers (Ps) applyed in therapies proposed in Chapter 1, and compare them with commonly used disinfectants in clinical practice; Chapter 3) Check the genotoxic potential of PACT and the production of Reactive Oxygen Species (ROS), with cytometric test associated with the fluorescent compound H2DCF-DA, and testing of DNA damage on C. albicans cells; Chapter 4) Development of a device patent design made for antimicrobial phototherapy (PACT) for disinfection of prosthetic materials. For the studies carried out with use of PACT, the experimental groups were divided as follows: not treated (P-L-); irradiated only (P-L+); only stained (P+L-); stained and irradiated (P+L+); and positive controls. The results determined that the best PACT association was TBO or MB with LED 630 nm/1 W, obtaining reduction of fungal viability of the biofilm from 2 to 4 log. The Ps did not cause surface roughness change, color change, or mass loss, when compared to chemical disinfectants. PACT caused DNA damage on C. albicans cells (113.7 ± 4.818), when compared to the negative controls (17.03 ± 1.138) (p <0.0001), by analyzing comet assays (µm). There was an increasing of ROS production when the P was subjected to irradiation (P+L+), compared to other groups. Therefore, PACT showed to be a promising therapeutic approach against C. albicans.