FRACTURE-TOUGHNESS OF RESIN-MODIFIED GLASS IONOMERS

Purpose: To measure and compare the fracture toughness of a multi-purpose resin composite, four light-cured glass ionomers, one light-cured resin ionomer, and two silver-containing glass ionomers. Materials and Methods: Ten specimens were fabricated for each of the eight materials: Herculite XRV, Fuji II LC, Photac-Fil, Vitrebond, Photac-Bond, VariGlass VLC, Ketac-Silver, and Miracle Mix. All materials were handled according to manufacturers' instructions during specimen fabricatian, stored in 100% humidity for 2 weeks, and tested wet in a universal testing machine. Results: The mean fracture toughness values (MPa . m(0.5) +/- S.D.) were: Herculite XRV = 1.17 +/- 0.09, Fuji II LC = 1.37 +/- 0.10, Photac-Fil = 1.27 +/- 0.08, VariGlass = 0.90 +/- 0.07, Vitrebond = 0.88 +/- 0.06, Photac-Bond = 1.09 +/- 0.09, Ketac-Silver = 0.51 +/- 0.08, and Miracle Mix = 0.30 +/- 0.07. There was a significant difference in the means (ANOVA P<0.0001). Fuji II LC and Photac-Fil were significantly tougher than any of the other materials (Tukey's HSD test P < 0.01).