Tissue Compatibility of Newly Developed Bioceramics

Abstract

Alumina ceramic (Bioceram®) is an excellent material that is stable in and compatible with biological tissues, though harder and more fragile than antogenous bone. Recently, new ceramics have been developed for the purpose of overcoming the disadvantages of alumina ceramics. For example, zirconia ceramics have almost the same flexural strength as iron and hydroxy apatite consists of the same molecular elements as autogenous bone.
Tissue compatibilities and radiological properties of three ceramics were investigated. First, tissue culture dishes (30 mm in diameter and 5 mm in depth) were made of the three ceramics and the adherence of cultured tumor cells to these dishes at 37°C for 90 minutes were compared with glass dishes and plastic culture dishes (Nunclon®). There was no difference in adherence between alumina ceramics and zirconia ceramics, both of which are superior to hydroxy apatite. Next, the growth rate for 1 week of cultured tumor cells on the ceramic dishes were examined. There were no differences between the three ceramics with regard to doubling time, while the growth rate on alumina ceramics exceeded that of the other ceramics. Thirdly, ceramic pieces were implanted in the parietal bone of mongrel dogs and histological changes, especially new bone formation, were investigated. Tongue-like exostosis of new bone along the ceramic piece was observed 2 months after implantation of alumina ceramic and 3 months for zirconia ceramic. Tissue reaction was slight. Finally, the artifacts of each ceramic on computerized tomography (CT) scan image were investigated. In the application of ceramics to neurosurgical field, artifacts on CT scan are an obstacle. Alumina ceramic showed minimum artifact on CT scan.
Alumina ceramic is considered to be the most suitable material among the three ceramics in the neurosurgical field at present.