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Tissue reaction around metal implants observed by X-ray scanning analytical microscopy
1Department of Dental Materials and Engineering, School of Dentistry, Hokkaido University, Sapporo, Japan. uo@den.hokudai.ac.jp
Biomaterials
|March 15, 2001
Summary
X-ray surface analysis (XSAM) revealed that nickel (Ni) and copper (Cu) implants caused severe tissue damage, while iron (Fe) implants led to fibrous tissue formation. This study highlights metal implant toxicity and dissolution behavior in soft tissues.
Area of Science:
- Biomaterials Science
- Toxicology
- Materials Science
Background:
- Biocompatibility of metallic implants is crucial for medical devices.
- Understanding metal ion dissolution and tissue response is essential for predicting implant performance and safety.
Purpose of the Study:
- To investigate the dissolution behavior and tissue response of various metallic implants (Cu, Ni, Fe, Ag, Ti, Ni-Ti, SUS304, SUS316) in soft tissues.
- To evaluate the relationship between dissolved metal element distribution and observed tissue reactions.
- To assess the utility of X-ray surface analysis (XSAM) in characterizing metal dissolution and distribution.
Main Methods:
- Implantation of metallic wires (Cu, Ni, Fe, Ag, Ti, Ni-Ti, SUS304, SUS316) into soft tissues.
- Analysis of implanted tissues using X-ray surface analysis (XSAM) to detect and quantify dissolved metal elements.
- Histological examination of surrounding tissues to assess tissue response.
- Preparation of standard specimens for quantitative concentration estimation by XSAM.
Main Results:
- XSAM clearly observed dissolution for Ni, Cu, and Fe implants.
- Severe tissue damage was associated with Ni and Cu implants, while Fe implants induced fibrous connective tissue formation.
- Estimated dissolved concentrations were approximately 10-20 mm for Ni and Cu, and significantly higher for Fe.
- Toxicity ranking at equivalent concentrations was Ni > Cu > Fe.
- Ag, Ti, Ni-Ti, SUS304, and SUS316 implants showed no significant dissolution or severe tissue damage.
Conclusions:
- XSAM is highly effective for analyzing the dissolution and distribution of trace amounts of toxic and chemically unstable metals in soft tissues.
- The study provides critical data on the differential biocompatibility of common metallic implant materials.
- Understanding metal ion release mechanisms and their toxicological effects is vital for designing safer and more effective medical implants.