Abstract
This study was investigated to clarify the biocompatibility of implant materials by means of MC3T3-E1 osteogenic cell line established from newborn mouse calvaria. These cells have the ability to differentiate into osteoblasts in vitro and to deposit hydroxyapatite crystals on extracellular matrix produced by them. So they seem to be more suitable than fibroblasts for the in vitro evaluation of implant materials, since the materials are mostly applied into bone. The materials used in this study are aluminium oxide (single crystal and poly crystal), titanium, zirconium, palladium-alloy, thermanox plastic cover slip (control). Disks (diameter: 10 mm, thickness: 1 mm) of these materials were placed in Φ60 mm plastic dishes. On these disks, 3, 000/disk of cells were inoculated and cultured in 5ml of α-MEM supplemented with 10% fetal bovine serum. On 2 days of culture, the cells on titanium and zirconium were thick and spindle in shape, similarly to them grown on plastic dishes.
To study the effect of implant materials on cell growth, differentiation and calcification, the cells were cultured for 17 days. The protein and DNA contents in the cells cultured on titanium and aluminium oxide were significantly greater than those on the other materials. Titanium and aluminium oxide poly crystal hastened cell growth. The values of alkaline phosphatase activity were high on titanium and zirconium. The capability of collagen synthesis has been examined using tritium proline. Zirconium was the most capable material on the proportion of collagen to protein synthesized. Titanium and zirconium accelerated cell differentiation. Ca and P contents were the highest on titanium, while they were lower on the other materials than those on control.
In conclusion, these results suggest that titanium has very well biocompatibility to the bone tissue as an implant material.
