Effects of glass chemistry on the optical properties of highly translucent alumina-glass biocomposites for dental restorations

Abstract Glass-infiltrated ceramic biocomposites have shown high strength and toughness, which results in long lifetime, but their translucency is relatively low, limiting the aesthetic quality of dental restorations. This study evaluated the effects of glass compositions based on the system SiO 2 -B 2 O 3 -Al 2 O 3 -La 2 O 3 -TiO 2 -CaO-CeO 2 , designed using SciGlass software, on the optical properties of alumina-based biocomposites. For (45-x)SiO 2 -xB 2 O 3 -25Al 2 O 3 -15La 2 O 3 -15TiO 2 glasses, the increase in B 2 O 3 content enhanced the infiltration of glass in the alumina preform because of the decrease in glass viscosity. The addition of CaO enhanced the infiltration depth and increased light transmittance of the biocomposite in the visible region (wavelength between 360 and 740 nm); however, the addition of CeO 2 significantly decreased the transmittance, particularly at the low wavelength range, because of the coloring effect (yellowish color due to the formation of cerium-titanium complexes). The highest transmittance was measured for biocomposites infiltrated with glass of composition 25% SiO 2 -20% B 2 O 3 -20% Al 2 O 3 -15% La 2 O 3 -15% TiO 2 -5% CaO (mol%).