Glass-ceramics in the CaO-MgO-Al2O3-SiO2 system as potential dental restorative materials

This paper reports on development of novel alumina-containing glass-ceramics (GCs) with a high content of Al2O3 (12.5 wt.%) in the CaO-MgO-Al2O3-SiO2 system aimed for dental restorations. The thermal properties of the parent glasses, the microstructure and the mechanical properties of the produced sintered and crystallized GCs along with bio-inertia performance were experimentally studied. Dense, white, and bio-inert GCs, comprised of melilite, either as a single-phase or with diopside, were produced. The values of flexural strength ranged between 120 and 171 MPa, the modulus of elasticity varied between 28 and 42 GPa, while the values of the hardness and the fracture toughness (measured by the indentation-Niihara equation) ranged from 6.3 to 7.0 GPa, and from 2.6 to 2.8 MPa m(0.5), respectively. The mechanical properties of the produced GCs, after being meticulously compared with the mechanical properties of GCs of various compositions reported in literature, including commercial ones, are a good match to the properties of dental hard tissues, and satisfy the requirements of the ISO 6872 "Dentistry-Ceramic Materials".