This present study will evaluate: a) the influence of composition and pre-heating of different experimental low viscosity resins on degree of conversion (DC), mechanical properties (flexural strength - FS, elastic modulus - E, sorption and solubility) and penetration coefficient (PC); b) penetration degree of these materials, observed by confocal microscopy, in artificial enamel caries lesions. Nine infiltrants will be assessed: 1 - commercially available product Icon®; 2 - 25% BisEMA + 75% TEGDMA; 3 - 20% BisEMA + 60% TEGDMA + 20% ethanol; 4 - 20% BisEMA + 60% TEGDMA + 20% acetone; 5 - 20% BisEMA + 60% TEGDMA + 20% HEMA; 6 - 100 % TEGDMA; 7 - 80% TEGDMA + 20% ethanol; 8 - 80% TEGDMA + 20% acetone and 9 - 80% TEGDMA + 20% HEMA, and each one of these resins will be tested under different conditions of temperature (25°C and 55°C), due to pre-heating. DC will be measured using Fourier Transform infrared spectroscopy (FTIR) and calculated by comparing the spectra from samples before and after light activation (n=5). For the mechanical test (E / FS), bar shaped specimens (7mmX2mmX1mm) will be prepared to be tested using the three-point exural test, at a crosshead speed of 0,5 mm/min. For water sorption and solubility tests, after desiccation, polymerized samples will be weighed, stored in distilled water for 7 days and, after further drying, will be weighed again, until obtaining a constant mass. Infiltrants PC will be calculated based on experimental conditions using a viscosimeter whereby contact angles, viscosities and surface tensions values will be obtained. Penetration depth analysis of different resins, pre-heating or not, in artificial enamel caries lesions will be performed through confocal laser scanning microscopy (CLSM) images by fluorescent markers impregnation of tested materials and infiltrated dental fragments. Therefore, all data will be submitted to appropriate statistical analysis.
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