title: Flexural strength and flexural fatigue properties of resin-modified glass ionomers.
abstract: OBJECTIVE
  To determine the physical properties of several resin-modified glass ionomers (RMGIs) by means of flexural strength and flexural fatigue testing, and to compare them to conventional glass ionomer cements (GICs) and flowable composite resins.
  
  
  METHODS
  RMGI samples were fabricated according to ISO 4049 standard. Rectangular specimens were produced using a polytetrafluoroethylene (PTFE) mold with dimensions of 2 x 2 x 25 mm. Flexural strength and flexural fatigue were measured by means of the 3-point bending tests using an Instron universal testing machine at 0.75 mm/min and 0.03 Hz for 100 cycles, respectively. Flexural stress, load, and displacement were recorded for all tests. Data were statistically compared (ANOVA, SNK, p < 0.05). Statistical data analysis for flexural fatigue was achieved through the least frequent events method (failures versus non-failures). The following RMGIs, flowable composites, and GICs were tested: 1) Activa Bioactive-Restorative; 2) Activa Bioactive-Base/Liner; 3) Tetric EvoFlow; 4) Beautifil Flow Plus; 5) Geristore; 6) Fuji Filling LC; 7) Fuji Lining LC; 8) Ketac Nano; 9) Fuji Triage; 10) Ketac Nano; and 11) Vitrebond Plus.
  
  
  RESULTS
  The flexural strength of Activa-enhanced RMGIs was statistically significantly greater than all other RMGIs and GICs (p < 0.001). The flexural fatigue of Activa-enhanced RMGIs and flowable composites was significantly greater than all other materials (p < 0.00 1). The flexural fatigue of the Activa-enhanced RMGIs was comparable to the two flowable composites tested.
  
  
  CONCLUSIONS
  The Activa-enhanced RMGIs demonstrated comparable flexural strength and flexural fatigue to flowable composites. Activa-enhanced RMGIs and flowable composites demonstrated flexural strength and flexural fatigue significantly greater than all other tested materials.
authors.forename: Cornelis H
authors.initials: CH
authors.lastname: Pameijer
authors.forename: Franklin
authors.initials: F
authors.lastname: Garcia-Godoy
authors.forename: Brian R
authors.initials: BR
authors.lastname: Morrow
authors.forename: Steven R
authors.initials: SR
authors.lastname: Jefferies
mesh_terms: D003799:Dental Stress Analysis; D055119:Elastic Modulus; D005899:Glass Ionomer Cements / Q000737:chemistry*; D008422:Materials Testing; D018583:Pliability; D019279:Resin Cements / Q000737:chemistry*; D013499:Surface Properties; D014783:Viscosity
chemical_list: D005899:Glass Ionomer Cements; D019279:Resin Cements