The effect of aging methods on the fracture toughness and physical stability of an oxirane/acrylate, ormocer, and bis-gma based resin composites

Dental resin composites have shown to degrade once placed in the oral cavity. This degradation affects the material’s physical stability and mechanical properties. The development of an alternative dental resin composite was an attempt to overcome these issues. But it remains unclear whether the oral environment affects the fracture toughness of alternative formulations of these materials.

The objective of this study is to evaluate the fracture toughness and volume change of three dental composite materials with different formulations, including an experimental composite, after an oral environment simulated challenge. The study looked at the effect of two environmental challenges, 15 days of biofilm challenge and 30 days of water storage, on the fracture toughness of the tested materials. Three specimens from each group were randomly selected and subjected to micro computed topography (μCT) analysis before and after the challenges to evaluate any volumetric and surface area changes, followed by fracture toughness testing for all samples. The statistical analysis showed that the environmental challenges negatively affected the fracture toughness of the two commercially available materials. However, the experimental resin composite demonstrated a different behavior with an increase in the fracture toughness after storage in water and no decrease after exposure to a 15-day biofilm. There was no significant change in the volume and the surface areas of the three tested materials.

Within the limitation of this study, we concluded that the two environmental challenges reduced the fracture toughness of the commercially available dental resin composites but did not negatively affect the experimental dental resin composite.