The effect of sodalite zeolite infiltrated material on the fracture toughness, elastic modulus and optical properties of all-ceramic dental prostheses

Abstract All-ceramic dental prostheses have been advocated for their superior esthetics. Although different materials and systems have been fabricated to improve the fracture resistance, their influence on the opacity of all-ceramic systems remains unclear. The purpose of this study was to investigate the effect of infiltrated materials on the fracture and optical properties of alumina and zirconia-toughened alumina (ZTA) frameworks. Ceramic core materials were prepared as disc-shaped samples measuring 16 mm in diameter and 1.2±0.2 mm in thickness for fracture toughness and elastic modulus tests, and 11 mm in diameter and 0.7±0.2 mm in thickness for translucency test. The case-study groups were synthesized sodalite zeolite-infiltrated alumina (IA-SOD) and synthesized sodalite zeolite-infiltrated ZTA (IZ-SOD), while the control groups were glass-infiltrated alumina (IA-glass) and glass-infiltrated ZTA (IZ-glass). The values of fracture toughness (Vickers microhardness), elastic modulus (fracture stress curve), as well as the relative translucency and brightness (contrast ratio from luminous reflectance) were compared among the groups (n=10). Scanning electron microscopy and energy dispersive X-ray spectroscopy were used to investigate the structural characteristics and crack patterns of the samples at the surface impression of a Vickers indenter. The collected data were analyzed with a one-way ANOVA and Tukey HSD test (α=0.05). IZ-SOD and IA-glass exhibited the highest fracture toughness and elastic modulus among the groups, respectively. Whereas IA-SOD showed the highest translucency and brightness. The results of this study thus confirmed the improvement in the optical properties of newly-developed IA-SOD as well as the fracture toughness of IZ-SOD frameworks and reveal the lower values of elastic modulus in SOD-infiltrated frameworks than glass-infiltrated samples (IA-glass and IZ-glass). These desirable features of SOD-infiltrated frameworks could thus make them suitable for anterior teeth restorations.