title: Failure and behavior in water of hydroxyapatite whisker-reinforced bis-GMA-based resin composites.
abstract: Failure mode under Hertzian indentation and the behavior on immersion in water of bis-GMA-based composites with HA whiskers or nanoscopic HA powder as filler were evaluated. Failure load decreased with increase in filler loading, but the decrease was smaller for whiskers, which showed a different failure mode both macroscopically and microscopically. Particle-filled composites failed mainly by radial cracking and cone cracking, with some plastic deformation at low filler loading, with fracture into irregular segments. For whisker-filled materials, crack propagation was inhibited by the well-dispersed whiskers by the usual toughening mechanisms; cone cracking was the dominant failure mode, at higher loads than for the powder, and fracture was incomplete. The filler reduced both water-uptake and elution of soluble materials, as expected, but both were lower for the whisker-filled material. Such composites might form the basis of viable materials for dental load-bearing restorations and other applications.
authors.affiliation: School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China.
authors.forename: Hongquan
authors.initials: H
authors.lastname: Zhang
authors.forename: Brian W
authors.initials: BW
authors.lastname: Darvell
mesh_terms: D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent; D017886:Durapatite / Q000737:chemistry*; D004852:Epoxy Compounds / Q000737:chemistry*; D008422:Materials Testing; D055595:Mechanical Phenomena; D008689:Methacrylates / Q000737:chemistry*; D012117:Resins, Synthetic / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D004852:Epoxy Compounds; D008689:Methacrylates; D012117:Resins, Synthetic; D014867:Water; D017886:Durapatite; C007870:glycidyl methacrylate