[Effect of gilding technique on the release of elements from copper-based alloy post-core]

To evaluate the effect of gilding technique on the release of element from copper-based alloy post-core exposed to artificial saliva.

The quantities of nickel ion and copper ion released from common copper-based alloy post-core (control group), blasting gilding copper-based alloy post-core (blasting group) and burnishing gilding Copper-based alloy post-core (burnishing group) in artificial saliva after 1 month,3 months,6 months and 8 months of exposure were measured with atomic absorption spectrophotometer. The tooth tissues were stripped off at the eighth month and the oxygenization on the surface of the posts were observed.

There was a significant difference of element release of nickel between the gilding groups and the control group at the sixth and eighth month. There was a significant difference of element release of copper between the gilding groups and the control group at the third, sixth and eighth month. The quantities of element released from the gilding groups were fewer than those from the control groups. The release of nickel and copper ions increased with the length of exposure significantly after three month of exposure. The element release from the control groups increased more rapidly than the gilding groups. The surface of the post-core in the control groups were all oxygenized while those in the gilding groups had been oxygenized only near the margins of the cores and the upper 1/3 part of the post with uncontinuous and relatively thin layers.

Gilding surface treatment can decrease the release of nickel and copper ions from copper based-alloy post-core and the surface oxygenization, which will improve the biocompatibility of the core.