Biocompatibility evaluation of nikel in vivo and in vitro

1986 Fiscal Year Final Research Report Summary

• Project/Area Number: 60570900
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: 補綴理工系歯学
• Research Institution: Hokkaido University
• Principal Investigator: NODASAKA Nobuyoshi School of Dentistry, Hokkaido Univ., Assistant, 歯学部, その他 (30184005)
• Co-Investigator(Kenkyū-buntansha): OHTA Mamoru School of Dentistry, Hokkaido Univ., Prof., 歯学部, 教授 (90013838) ; ONOKI Masaaki School of Dentistry, Hokkaido Univ., Lccturer, 歯学部, 講師 (70002300) ; KAGA Masayuki Dental Hospital, Hokkaido Univ., Lccturer, 歯学部附属病院, 講師 (70125300)
• Project Period (FY): 1985 – 1986
• Keywords: Cytotoxicity of Base Metal Ims / Biocompatibility evaluation of Base Metal Ions in rat / Subcutaneous tissue / <N^(2+)> / <Co^(2+)>

Research Abstract

1. The macroscopical observation revealed that the tissue around the nickel underwent severe inflammatory changes accompanied by swelling and redness. On the seventh day of the experiment, histopathological examination revealed following in these masses: a necrotized tissue in contact with the nickel, a severe inflammatory tissue layer with inflammatory cell infiltration, a narrow bleeding layer, and a network-structure of fibrous tissue with numerous capillaries.
2. The tissue around the base metal casting alloys did not show any gross changes nor histopathological findings in the almost all of the experiments. The tissues around the metal were composed of fine fibrous tissue layers without inflammatory cell infiltration and granular foci, which revealed good biocompatibility. A small amount of <Ni^(2+)> was, however, detected in the tissue around these metals.
3. The experiments showed that nickel, which causes serious inflammation in the tissue, is released from casting base metal alloys by corrosion and remains in the surrounding tissue without destroying it. Even when there was no evidence of any cellular changes in the surrounding tissue, small amounts of <Ni^(2+)> were detected.
4. SEM observations revealed that the cells in the medium containing each metal ions showed degenerative changes. In the nickel cultures, spindle-like fibroblasts were changed into polygonal-shaped cells without dividing processes and villi on the rough cell surface. The cell membranes were partly destroyed and organelles were exposed. These morphological changes and depressions in the cell growth rate were found to result from high concentrations of nickel and cobalt and low concentrations of chromium. After incubation for six days, these metal ions could be arranged in the following order of cytotoxicity: <Cr^(6+)> > <Co^(2+)> > <Ni^(2+)> .