title: The effect of thermal cycling on the fracture toughness of seven composite restorative materials.
abstract: Short-red chevron-notch samples of seven composite materials were thermal-cycled between 0 degrees C and 60 degrees C. The stress intensification factor, KIC, was found for four sample groups subjected to 10(1)-10(4) cycles, respectively. One group of uncycled samples was tested at the commencement of the investigation and another group after exposure to water for the equivalent time taken by 10(4) cycles (42 days). The KIC decreased for all materials, but the decrease after 10(4) cycles was not significantly different from that after storage in water for an equivalent period of time. These results indicate that, in the determination of KIC, the filler/matrix bond is of secondary importance to the presence of fillers. The effects of cyclic temperature changes likely to be encountered in the mouth are not a significant factor in reduction of the fracture strength of composite filling materials.
authors.forename: L H
authors.initials: LH
authors.lastname: Mair
authors.forename: R
authors.initials: R
authors.lastname: Vowles
mesh_terms: D003188:Composite Resins; D003799:Dental Stress Analysis; D006358:Hot Temperature
chemical_list: D003188:Composite Resins