Fracture toughness of resin-based luting cements☆☆☆★

Abstract 

Statement of problem. The introduction of resin-modified glass ionomer cements has expanded the choices of luting cements available to the clinician; however, few independent studies are available on the fracture toughness of the currently available resin-modified glass ionomer luting agents compared with the composite cements. Purpose. This investigation evaluated the relative fracture toughness (K_IC) of 3 composite luting cements (Panavia 21, Enforce, and C&B Metabond), 3 resin-modified glass ionomer luting cements (Advance, Vitremer Luting, and Fuji Duet), and a conventional glass ionomer luting cement (Ketac-Cem) at 24-hour and 7-day storage times. Material and methods. K_IC was determined by preparing minicompact test specimens (n = 8) with introduced precracks. Specimens were stored in distilled water at 37°C + 2°C until testing. Testing was performed on an Instron testing machine at a displacement rate of 0.5 mm/min. Results. ANOVA (P <.001) and REGW Multiple Range Test (P <.05) demonstrated significant differences among several of the cements tested. The mean fracture toughness values of C&B Metabond at 24 hours and Enforce at both 24 hours and 7 days were significantly greater than use any of the other cements tested. Conclusion. The resin-modified glass ionomer cements exhibited improved fracture toughness when compared with the conventional glass ionomer; however, they were still inferior to Enforce and C&B Metabond composite cements. (J Prosthet Dent 2000;83:204-9.)