Dental castable glass ceramics: ceramming treatment and colour property

Abstract

The magnitudes of colour change vector and lightness were examined for 20CaO/10P₂O₅/10MgO/10Al₂O₃/50SiO₂ glass ceramics (B₂O₃/CaF₂=0.01 wt % 0.01 wt %, mass fraction). The glass ceramics were thermally treated (cerammed) for crystallization at each selected temperature (800 to 980°C for each ceramming period) within a steel ring including the investment mould. Cristobalite-quartz investment mould exhibited no adhesive mould interfaces, showing that the magnitudes of colour change vector and lightness ranged from 17.60 (890°C) to 37.05 (980°C) and 55.77 (890°C) to 71.42 (980°C) for glass ceramics, respectively, after thermal treatment for 2 h (sample thickness 2 mm). The thermal treatment controlled the colour property measured by colour analyser as compared the cerammed samples with bovine enamel and human tooth enamel.