Preparation of nepheline glass–ceramics for dental applications

Nepheline containing glass–ceramic with fine uniform microstructure was achieved from a glass composition midway between nepheline and anorthite for dental crown construction. The crystallization of nepheline solid solution was confirmed by the XRD as depicted by the d-spacing lines at 3.45 and 3.34 Å. The incorporation of TiO2 reduces the softening and crystallization temperature and enhances the fineness. The prepared glass–ceramics displayed coefficients of thermal expansion in the range of 70–85 × 10−7 K−1 (25–300 °C). The fact that insured good bonding between ceramic and metal components in dental prosthesis. The addition of CaO on the other hand, improves the dimensional stability and the chemical resistance. In addition, a deficiency in both Na2O and SiO2 and abundance of CaO and Al2O3 was detected by EDX analysis, the case confirming a coupled solid solution where Na+1Si+4 substitute Ca+2Al+3.