OBJECTIVETo evaluate the biological safety of compound galvano-ceramic bridge by measuring the consistency of released nickel ion of the galvano-form slices cohered with Ni-Cr alloy slice specimens which were immersed in artificial saliva.

METHODSSpecimens were divided into five groups with four tests and one control. Test specimens were made into the structure like rectangle sandwich that one side of Ni-Cr alloy was cohered to the center surface of galvano golden base of 0.2 mm and another side was fused porcelain with the thickness of 0.3 mm (group A), 0.5 mm (group B), 1.0 mm (group C), and 0.3 mm (group D). And the Ni-Cr alloys were totally embedded in galvano golden base and firing porcelain. Naked Ni-Cr alloy was taken as control. Group D was immersed into acid artificial saliva (AS) with high fluoride, while others were in acid AS at 37 degrees C for 120 h. Then the consistency of released nickel ion in the solution was measured with inductively coupled plasma-atomic emission spectrometry (ICP-AES).

RESULTSNickel ions detected in the artificial saliva for the groups A, B, C, and D in acid AS with or without high fluoride were all under 0.005 mg/L Significant differences were found between each test group and the control [(0.65 +/- 0.45) mg/L].

CONCLUSIONSGalvano-ceramic bridge, Ni-Cr alloy bridge with fused porcelain and golden base, shows biological safety responsible for the consistency of released nickel ion.