IADR Abstract Archives
The Effect of Ethanol Aging Upon the Hardness of Experimental Resin Composites
Objectives: The longevity and durability of resin composite dental materials is likely to be influenced by dietary constituents. Specifically, the consumption of alcoholic beverages has a potential for increasing the degradation rate of these materials. This in vitro study aimed to evaluate the hardness of unfilled and hybrid model composite materials before and after immersion in three different media for a period of time up to 21days
Methods: Experimental materials based on a mixture of 70wt%:30wt% BisGMA/TEGDMA, with 1wt% each of camphorquinone and ethyl 4-(dimethylamino)benzoate as photo-initiators, to which 0, 30 and 45 vol% silica filler (particle size 2.5µm, 0.7µm, 3:1 Ratio ) were added by mechanical mixing. Disc specimens (12mm X 3mm, n=45) were made for each material in acrylic moulds. Specimens were polymerized for 20s on both faces (Bluephase®20i-Ivoclar Vivadent, 1000 mW/mm2) and then stored in three different solutions (phosphate buffered saline (PBS), 50 % Ethanol-Water or 100% Ethanol) at 37C for up to 21 days. Hardness values of the specimens were recorded (Zwick Z2.5) both before and after storage for 1, 7, 14, 21 days in each tested solution (3 indents per disc).
Results: The materials generally showed a significant increase in hardness related to filler loading. For the 0% filled material, storage in test solutions for the examined time led to a significant decrease in hardness (P<0.05, Kruskal-Wallis). For the filled materials (30% & 45%), storage in PBS showed no statistically significant effect on hardness (P>0.05); while storage in 50% or 100% ethanol media demonstrated a significant lowering effect on hardness over time (P<0.05).
Conclusions: The obtained results suggest that all tested materials were susceptible to a decrease in hardness on exposure to ethanol over time. However, filler content has a direct effect on increasing hardness of the experimental composite.
Methods: Experimental materials based on a mixture of 70wt%:30wt% BisGMA/TEGDMA, with 1wt% each of camphorquinone and ethyl 4-(dimethylamino)benzoate as photo-initiators, to which 0, 30 and 45 vol% silica filler (particle size 2.5µm, 0.7µm, 3:1 Ratio ) were added by mechanical mixing. Disc specimens (12mm X 3mm, n=45) were made for each material in acrylic moulds. Specimens were polymerized for 20s on both faces (Bluephase®20i-Ivoclar Vivadent, 1000 mW/mm2) and then stored in three different solutions (phosphate buffered saline (PBS), 50 % Ethanol-Water or 100% Ethanol) at 37C for up to 21 days. Hardness values of the specimens were recorded (Zwick Z2.5) both before and after storage for 1, 7, 14, 21 days in each tested solution (3 indents per disc).
Results: The materials generally showed a significant increase in hardness related to filler loading. For the 0% filled material, storage in test solutions for the examined time led to a significant decrease in hardness (P<0.05, Kruskal-Wallis). For the filled materials (30% & 45%), storage in PBS showed no statistically significant effect on hardness (P>0.05); while storage in 50% or 100% ethanol media demonstrated a significant lowering effect on hardness over time (P<0.05).
Conclusions: The obtained results suggest that all tested materials were susceptible to a decrease in hardness on exposure to ethanol over time. However, filler content has a direct effect on increasing hardness of the experimental composite.