Effect of Crystallinity on Strength and Fracture Toughness of Li ₂ O‐Al ₂ O ₃ ‐CaO‐SiO ₂ Glass‐Ceramics

Abstract

The influence of crystal volume fraction on fracture toughness ( K I C ) and indentation strength was analyzed for Li 2 O‐Al 2 O 3 ‐CaO‐SiO 2 (LACS) and LACS glass‐ceramics containing 0.58 mmol% AgNO 3 (LACS‐0.58Ag) or 0.78 mmol% AgNO 3 (LACS‐0.78Ag). The mean flexure strength, indentation strength, and K I C values of the LACS‐0.78Ag groups increased with volume fraction of crystallinity. To achieve the greatest strength and K I C in LACS‐Ag specimens, a high volume fraction of crystallinity (95%) had to be produced. However, the relationship between volume fraction of crystal phase and translucency had to be analyzed to determine the influence of crystallization on the potential esthetic results that are essential for dental applications. Addition of AgNO 3 to LACS glass produced a change from surface crystallization to bulk crystallization.