| Research Abstract |
To clarify the tumorgenicity of titanium alloys for dental implants, the dissolution of these alloys immersed in amino acid solutions and mutagenicity of the released substances from the alloys were studied.
1) Four alloys, NiTi,Ti6A14V, Ti5A12.5Fe and Ti5A13Mo4Zr were grinned to a fine powers using a freeze mill. Three hundred mg of each powder was immersed in 5 ml of 0.1M cysteine solution or 0.1M glutathione solution under rotation at speed of 15rpm at 37ﾟC. After 2 weeks, the extracts were analyzed of Ti, Al, V, Fe, Mo and Ni by an atomic absorption spectrophotometer or Inductively Coupled Plasma emission spectrometer (ICP). The average leakage of Ti, Al and V from Ti6A14V alloy to glutathion solution were 31.6, 400 and 79.6 pg/mg of alloy/day respectively. The average leakage of Ti to a cysteine solution was 1.5 pg/mg of alloy/day.
2) The frequency of the Unscheduled DNA Synthesis (UDS) were studied in HeLa cells exposed to the extracts. No significant increase in the frequency of UDS were observed.
3) The frequency of exchange of Sister Chromatides (SCEs) were studied in V79 cells exposed to the extracts. The frequency of SCEs in V79 cells treated with glutathione extracts of a Ti5A13Mo4Zr alloy were increased about 3 times that a glutathione solution control. A significant increase in SCEs could be demonstrated. The genetic effects of titanium alloys dissolved substances are found.
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