Abstract: A biocompatible, strong, radio-opaque high melting glass is obtained by reacting at the melt mono-basic calcium phosphate with phosphoric acid and a radio-opaque-imparting component such as bismuth oxide (Bi.sub.2 O.sub.3) or barium oxide (BaO). After soaking, cooling and drying, the glass may be ground to desired particle size, and is admirably suited for use as a filler, binder, or structural mass in the dental and medical fields.