
Knoop microhardness and the degree of conversion of three packable composites (SureFil, Alert and Solitaire), a microfil composite (Heliomolar), a microhybrid composite (Herculite) and an indirect laboratory-processed composite (Belleglass) were evaluated as a function of distance from the irradiated surface. Cylindrical specimens (5.0 mm [diameter] x 6.0 mm [length]) of each material were visible light cured for 60 seconds in black-backed Teflon molds and sectioned. Knoop microhardness values were then obtained at 0-, 2- and 4-mm using a 50-gram load and 20 second dwell time. Degree of conversion was determined using Fourier Transform Infrared Spectroscopy. ANOVA (p<0.001) and Tukey Multiple Comparison Test (p<0.05) showed the indirect laboratory-processed composite Belleglass exhibited the highest mean values for both hardness and degree of conversion. Alert exhibited significantly greater hardness than SureFil and Solitaire at 0-mm depth. SureFil had significantly greater hardness than Alert at 4-mm depth. The degree of conversion of SureFil packable composite at 4-mm depth was significantly higher than any of the other direct composites tested.
Time Factors, Light, Polymers, Surface Properties, Polyurethanes, Acrylic Resins, Composite Resins, Hardness, Materials Testing, Spectroscopy, Fourier Transform Infrared, Humans, Methacrylates, Stress, Mechanical
Time Factors, Light, Polymers, Surface Properties, Polyurethanes, Acrylic Resins, Composite Resins, Hardness, Materials Testing, Spectroscopy, Fourier Transform Infrared, Humans, Methacrylates, Stress, Mechanical
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