Abstract
Titanium (Ti) and Ti alloys are widely used for dental materials. Recently, an aluminium and vanadium free titanium alloy, Ti-29Nb-13Ta-4.6Zr alloy, was developed. In the present study, we used the demineralized bone matrix (DBM) pellet for evaluating biocompatibility of Ti, Ti-6A1-4V alloy (the most widely used alloy) and Ti-29Nb-13Ta-4.6Zr alloy. The DBM pellet made of mouse long bones was implanted on the dorsal muscle of mice under ether anesthesia. After the DBM pellet had been implanted for 4 weeks, the expression of mRNA for osteoblastic and osteoclastic phenotypes and mineralization were observed, suggesting that the DBM could heterotopically induce bone. The DBM pellet combined with a disk of Ti, Ti-6A1-4V alloy and Ti-29Nb-13Ta-4.6Zr alloy was implanted in the mouse in the same way. Four weeks after the implantation, the calcium contents accumulated in the DBM pellet with Ti, Ti-6A1-4V alloy and Ti-29Nb-13Ta-4.6Zr alloy were 36.6±8.0 μ g, 50.4± 13.3 μ g and 75.6± 16.9 μ g, respectively. A significant difference was observed between Ti and Ti-29Nb-13Ta-4.6Zr alloy (p<0.05) . This result seemed to suggest the increase of the mineralization in DBM-induced heterotopic bone by Ti-29Nb-13Ta-4.6Zr alloy, because Ti particles showed no toxicities in mouse osteoblastic cells, in mouse bone marrow cells, and in isolated rabbit osteoclasts. These findings suggested that Ti-29Nb-13Ta-4.6Zr alloy might be a higher biocompatible material with bone tissue, and showed that the heterotopic bone induced by the DBM pellet in mice could be a simple and useful method for evaluating biocompatibility of titanium alloys.
