Relative flexural strength of six new ceramic materials.

The flexural strength of six recently introduced dental ceramic materials was measured using a three-point-bend test. Conventional feldspathic porcelain and soda-lime glass were used as controls. All six of the new materials had significantly greater breaking strength than the controls. The alumina-based crystalline-reinforced materials exhibited the highest breaking strengths. The silica-based crystalline-reinforced materials resulted in ceramic materials with more moderate strength but still with significantly greater strength than the controls. Scanning electron microscopic analysis of the fractured surfaces indicated crack deflection appeared to be the principal strengthening mechanism in the highly crystalline materials.