Radio-opaque nanosized bioactive glass for potential root canal application: evaluation of radiopacity, bioactivity and alkaline capacity

P>Aim To produce novel nanosized bioactive glass particles with radio-opaque properties and high alkaline capacity and to evaluate their performance as a potential bioactive root canal dressing or filling material. Methodology Flame spray-derived bioactive glass particles in the nanometre range were produced including bismuth oxide as a radiopacifier. Calcium hydroxide, barium sulphate and bismuth oxide served as controls. Corresponding materials were compressed to obtain dense specimens with increased alkaline capacity. Radiopacity was evaluated, and in vitro bioactivity was monitored using Raman spectroscopy and scanning electron microscopy. Leaching of bismuth was controlled using atomic absorption spectroscopy. Results Bioactive glass particles with up to 50 wt% bismuth oxide revealed radiopacity with an equivalent of 4.94-mm aluminium. The introduction of bismuth into the bioactive glass altered the alkaline capacity and the in vitro bioactivity only for high bismuth oxide quantities. Bismuth oxide leaching out of the glass matrix was hardly detectable. Conclusion Bioactive glass can be modified with bismuth oxide to become radio-opaque.