Biological safety evaluation of nano-hydroxypatite-zirconia ceramic

Objectives: It is the implant material which plays a crucial role in the whole procedure of rehabilitation. It is thus a great challenge for dentists to create a novelty implant material not only well accepted by the surrounding tissue, but also with desired mechanical properties. A combination of materials properties is thus expected to give a bioactive hydroxyapatite-containing implant material with improved mechanical properties. In this study we investigate the biological properties of the novel nano-hydroxyapatite-zirconia ceramic. Materials and methods: Two tests were taken up according to ISO standards including in vitro cytotoxicity test. The effects of different groups of nano-hydroxyapatite-zirconia ceramics on the proliferation of mouse fibroblast L929 cells were investigated using a tetrazolium-based colorimetric assay (MTT assay). The samples were tested at 2,4,7 days respectively after addition of extract. In the second experiment, acute hemolysis test was to evaluate the haemal compatibility of the bioceramics. Results: L929 cells showed normal morphology and proliferated gradually. The toxicity grades of all groups were 0 or 1. The hemolysis indexs were all below 3%. Conclusions: Densed nano-hydroxyapatite-zirconia ceramic showed good biological safety for clinical use in the future.