Cytotoxicity of Gallium and Indium Ions Compared with Mercuric Ion

Abstract

The use of mercury in dental amalgam restorations has become the subject of political controversy despite its long history of safe clinical use, and alternative materials based on gallium and indium rather than mercury have been developed. The biological safety of these metals must be evaluated, as part of their assessment as mercury substitutes. The cytotoxicities of mercury (II) nitrate, gallium (III) nitrate, and indium (III) nitrate were assessed at concentrations between 0.001 mmol/L and 1.0 mmol/L, using L929 mouse fibroblasts and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay and scanning electron microscopy. The mitochondrial dehydrogenase activity at each metal ion concentration as a percentage of the control was calculated from the absorbance values. The 50% inhibition concentration of mercury (II) nitrate was 0.35 mmol/L for cells in the rapid-growth phase and at confluence; gallium (III) nitrate and indium (III) nitrate did not significantly inhibit dehydrogenase activity in either the growing or confluent phase. Gallium and indium ions were not significantly toxic under the conditions of this assay.

Evaluation of the biocompatibility of titanium-tantalum alloy versus titanium

“…In contrast, no important differences were observed between cultures grown on titanium or on titaniumtantalum. The ultrastructural appearances of the cells were identical to those observed in other studies involving plastic substrates 15 or titanium debris. 16 The absence of significant morphological modifications has been reported in earlier studies, whether involving in vitro contact with titanium or alloys such as Ta6V, 17 or in vivo contact with Ti or Ta implants.…”

Screening on binary Ti alloy with excellent mechanical property and castability for dental prosthesis application

“…Ag and Ga has a long history of use in dental alloys, though the Ag + and Ga 3+ were reported to be relatively high cytotoxicity in vitro 31, the addition of 2 wt.% would not affect the good cytocompatibility of Ti, which was also proved in present study. Actually, Chandler et al 32. evaluated the effect of Ga 3+ and In 3+ and their concentration (0.001~1.0 mmol/L) on L929 cells.…”

Advanced metal–ceramic joining techniques for orthopaedic applications

“…Table 15.4 lists 72 viable fi ller metals produced by arc-melting; chemical composition is reported, starting with the base metal and giving the percentage weight content of alloying elements; melting and wetting behaviour and hardness are indicated as well (Sicking, 2000 ). Noble metals Au, Ag and Pd are fully biocompatible, Al and Sn are surely non-biocompatible, while the bio compatibility of In and Ga is still questionable, even if considered satisfactory in most literature (Kimura, 1988 ;Iijima, 1989 ;Chandler et al . 1994 ;Wataha et al ., 1994 ).…”