TY - JOUR
T1 - R-curve behavior and micromechanisms of fracture in resin based dental restorative composites
AU - Shah, M. B.
AU - Ferracane, J. L.
AU - Kruzic, J. J.
PY - 2009/10
Y1 - 2009/10
N2 - The fracture properties and micromechanisms of fracture for two commercial dental composites, one microhybrid (Filtek™Z250) and one nanofill (Filtek™Supreme Plus), were studied by measuring fracture resistance curves (R-curves) using pre-cracked compact-tension specimens and by conducting both unnotched and double notched four point beam bending experiments. Four point bending experiments showed about 20% higher mean flexural strength of the microhybrid composite compared to the nanofill. Rising fracture resistance was observed over ∼1 mm of crack extension for both composites, and higher overall fracture resistance was observed for the microhybrid composite. Such fracture behavior was attributed to crack deflection and crack bridging toughening mechanisms that developed with crack extension, causing the toughness to increase. Despite the lower strength and toughness of the present nanofill composite, based on micromechanics observations, large nanoparticle clusters appear to be as effective at deflecting cracks and imparting toughening as solid particles. Thus, with further microstructural refinement, it should be possible to achieve a superior combination of aesthetic and mechanical performance using the nanocluster approach for dental composites.
AB - The fracture properties and micromechanisms of fracture for two commercial dental composites, one microhybrid (Filtek™Z250) and one nanofill (Filtek™Supreme Plus), were studied by measuring fracture resistance curves (R-curves) using pre-cracked compact-tension specimens and by conducting both unnotched and double notched four point beam bending experiments. Four point bending experiments showed about 20% higher mean flexural strength of the microhybrid composite compared to the nanofill. Rising fracture resistance was observed over ∼1 mm of crack extension for both composites, and higher overall fracture resistance was observed for the microhybrid composite. Such fracture behavior was attributed to crack deflection and crack bridging toughening mechanisms that developed with crack extension, causing the toughness to increase. Despite the lower strength and toughness of the present nanofill composite, based on micromechanics observations, large nanoparticle clusters appear to be as effective at deflecting cracks and imparting toughening as solid particles. Thus, with further microstructural refinement, it should be possible to achieve a superior combination of aesthetic and mechanical performance using the nanocluster approach for dental composites.
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U2 - 10.1016/j.jmbbm.2008.12.005
DO - 10.1016/j.jmbbm.2008.12.005
M3 - Article
C2 - 19627857
AN - SCOPUS:67349124798
SN - 1751-6161
VL - 2
SP - 502
EP - 511
JO - Journal of the Mechanical Behavior of Biomedical Materials
JF - Journal of the Mechanical Behavior of Biomedical Materials
IS - 5
ER -