FRACTURE-ANALYSIS OF DENTAL COMPOSITES

Three dental composite materials were tested in three-point bending to determine fracture toughness using the stress intensity factor approa ch. Finite element analysis was used to model the specimens and the fr acture toughness was calculated using the J integral and crack closure methods. The effects of tension, compression, and tension-compression moduli on the fracture toughness are presented and discussed. For eac h material, the plain strain J integral results were independent of Yo ung's modulus. Crack closure results were found to be very sensitive t o the type of mesh used to define the DELTAa/a ratio at the crack tip. The results from J integral and crack closure methods were in good ag reement with experimental data for the three dental composites conside red.