Influence of Food Simulating Fluids and Thermocycling on Surface Roughness and Wear Resistance of Dental Composite Restoratives.

Abstract

Objective: The aim of the investigation was to evaluate the effect of food simulating fluids and thermocycling on surface roughness and wear resistance of CAD/CAM (Lava TM Ultimate, 3M ESPE), (SR Nexco® Paste, Ivoclar Vivadent) and (Filtek TM Z350 XT, 3M ESPE) resin composites.Methods: A total of 360 disks were fabricated and divided into three groups. Each group was divided into 12 subgroups (n=10); 6 subgroups for measuring surface roughness and the other 6 subgroups for measuring wear resistance. Four subgroups are immersed for 1 month in different food simulating fluids (distilled water, ethanol, heptane and citric acid). The fifth subgroup was thermocycled for 5000 cycle, while the control subgroups were examined after 24 hours postpolymerization. Surface roughness was assessed using environmental scanning electron microscope. Wear resistance testing was carried out by custom made toothbrush machine. The results were tabulated and statistically analyzed. Results:The results revealed that the food simulating fluids and thermocycling had a deteriorating effect on the three tested materials. Lava TM Ultimate showed the least significant deterioration when compared to SR Nexco® Paste and Filtek TM Z350 XT. Conclusion:Lava TM Ultimate had better resistance to both food simulating fluids and thermocycling, which may be due to its higher nanofillers percentage and its highly cross linked matrix.