Radiopacity vs. composition of some barium and strontium glass composites

Abstract

The radiopacity of a series of strontium- and barium-glass composites has been determined, together with the radiopacities of strontium- and barium-glass discs. The composites were highly filled, and thereby exhibited optimum radiopacity for a given filler type. Radiopacity was related to chemical composition of the filler, and a value in excess of that obtained for dental enamel could be achieved by three types of formulation containing: (1) a barium-glass filler; (2) mixed barium- and strontium-glass fillers (containing 35 per cent or more, by mass, of the barium glass in the total glass filler mixture); and (3) a glass filler with a strontium content equivalent to ca 40 per cent strontium oxide. However, this latter formulation has poor wear resistance. In general, a radiopacity in excess of enamel could be attained by composites containing more than 20 mass per cent of radiopaque oxide in the filler particles with a total volume fraction of filler ca 70 per cent, at a thickness of 2·5 mm.