Cytotoxicity of commercial and novel binary titanium alloys with and without a surface-reaction layer.

Titanium-based alloys form a surface reaction layer when cast. This study investigated the effect of the surface reaction layer on the cytotoxicity of novel Ti-based binary alloys. The cytotoxicities of the novel alloys were compared with commercially pure titanium, Ti-6Al-4V and Ti-6Al-7Nb. Cast discs with or without the reaction layer were first tested for cytotoxicity, then for elemental release into cell-culture medium. The elements released into the extracts were measured by means of an inductively coupled plasma atomic emission spectrometer. The commercial and novel binary Ti-based alloys showed no statistically significant cytotoxicity, although some trends were noted for several alloys. The presence of the reaction layer did not significantly alter the cytotoxicity. These favourable biocompatibility results show that these novel alloys have promise for use in dental restorations.