A comparison of the mechanical properties of three glass-ionomer cements.

A comparison was made on the mechanical properties of three glass-ionomer cements, one of which was of experimental fiber-reinforcing and auto-curing type. Two others were proprietary auto-curing and light-activating cements. Biaxial flexure test was conducted on disc samples. Three-point bending test was also carried out on bar samples to determine modulus of elasticity and strength. All samples were kept at 37 degrees C and 100% RH for 24 h before testing under ambient conditions. A prolonged fracture process was observed in the experimental cement, demonstrating the effect of fiber incorporation in stabilizing the fracture process. The proprietary cements failed in a brittle manner. Comparison of the mechanical properties identified three characteristics. These were a high Weibull modulus resulting from the stabilization in fracture process, a modulus of elasticity value comparable to that of dentin, and a high biaxial flexure strength close to that of a dental resin composite.