title: In vitro wear and fracture toughness of an experimental light-cured glass-ionomer cement.
abstract: OBJECTIVE
  The objective of this study was to evaluate the in vitro wear and fracture toughness (FT) of an experimental resin-modified glass-ionomer cement (RMGIC) formulated with the newly synthesized 6-arm star-shape poly(acrylic acid) and Fuji II LC glass fillers and investigate the effects of several important formulation parameters on wear-resistance and FT of the cement.
  
  
  METHODS
  The in vitro abrasive and attritional wear as well as FT of the newly developed RMGIC were evaluated. The resin composite P-60 and RMGIC Fuji II LC were used as controls. The effects of glycidyl methacrylate (GM)-grafting ratio, powder/liquid (P/L) ratio, polymer/water (P/W) ratio and aging in water were investigated. All the specimens were conditioned in distilled water at 37 degrees C for 1 day prior to testing, unless specified.
  
  
  RESULTS
  The optimized experimental cement exhibited almost the same high initial wear-resistance to abrasion as P-60 and much higher than Fuji II LC. The experimental cement showed 1.4 times higher in resistance to attritional wear than Fuji II LC but 6 times lower than P-60. After 1-month aging, the cement can compete with P-60 in resistance to attritional wear by showing only 1.3 times more in wear depth. The experimental cement also showed a significantly higher FT value than Fuji II LC but a similar value to P-60.
  
  
  CONCLUSIONS
  It appears that this novel experimental cement may be potentially used for high wear and high stress-bearing site restorations such as Class I and II.
authors.affiliation: Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhao
authors.forename: Yiming
authors.initials: Y
authors.lastname: Weng
authors.forename: Dong
authors.initials: D
authors.lastname: Xie
mesh_terms: D000180:Acrylic Resins; D003188:Composite Resins; D019554:Dental Restoration Wear; D003793:Dental Restoration, Permanent; D003799:Dental Stress Analysis / Q000295:instrumentation; D004852:Epoxy Compounds; D005899:Glass Ionomer Cements / Q000138:chemical synthesis / Q000737:chemistry; D008422:Materials Testing / Q000295:instrumentation; D008689:Methacrylates; D015394:Molecular Structure; D012117:Resins, Synthetic; D014867:Water
chemical_list: D000180:Acrylic Resins; D003188:Composite Resins; D004852:Epoxy Compounds; C079765:Fuji II LC cement; D005899:Glass Ionomer Cements; D008689:Methacrylates; C443708:P60 Condensible Resin Composite; D012117:Resins, Synthetic; D014867:Water; C006903:carbopol 940; C007870:glycidyl methacrylate