title: Mechanical properties of hydroxyapatite whisker-reinforced bis-GMA-based resin composites.
abstract: OBJECTIVE
  To evaluate the reinforcement efficacy of hydroxyapatite (HA) whiskers in bis-GMA-based dental restorative composites and determine the effect of volume fraction on the mechanical properties.
  
  
  METHODS
  Silanized HA whiskers and nano-scale powder were mixed in various proportions with bis-phenol A-glycidyl methacrylate (bis-GMA)-based polymer pastes. Equal parts of initiator and accelerator pastes were then mixed by hand. After curing at 25 ± 2 °C and storage in distilled water at 37 °C for 24h, elastic modulus, fracture strength and work-to-failure in three-point bending, fracture toughness using a notchless triangular prism fracture method, and Vickers hardness were determined. Data were examined by means of one-way analysis of variance and linear regression.
  
  
  RESULTS
  Reinforcing efficacy was significantly dependent on filler morphology. Whiskers had good dispersibility and wettability with bis-GMA-based polymer, conferring good reinforcement and toughening, significantly better than did the HA nano-scale powder.
  
  
  CONCLUSIONS
  HA whiskers provided better mechanical properties in bis-GMA-based composites compared with the nano-scale powder. Such whisker-reinforced materials may be beneficial compared with currently used dental restorative materials.
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: D017438:Bisphenol A-Glycidyl Methacrylate; D003188:Composite Resins / Q000737:chemistry*; D003460:Crystallization; D003793:Dental Restoration, Permanent; D003799:Dental Stress Analysis; D017886:Durapatite; D055119:Elastic Modulus; D006244:Hardness; D008422:Materials Testing; D055595:Mechanical Phenomena; D049329:Nanostructures; D010316:Particle Size; D018583:Pliability; D013718:Tensile Strength; D017155:Wettability
chemical_list: D003188:Composite Resins; D017438:Bisphenol A-Glycidyl Methacrylate; D017886:Durapatite