[Effects of the improved FUS-invest investment for zirconium-oxide titanium crown and bridge on the reaction layer].

Objective: To investigate the effects of the improved FUS-invest investment for zirconium-oxide titanium crown and bridge on the reaction layer.

Methods: 10 mm x 10 mm x 1 mm titanium castings were invested. Spectrum analysis was done to its reaction layer, the metallographic examination was observed and Vickers hardness was measured.

Results: The reaction layer was not obvious by the metallographic examination. The layer with plenty of Si was hardly detectable. The needle crystal layer diffused distribution on the surface of the titanium matrix. The depth was about 55 microm. Spectrum analysis showed that the contents of Si and Zr decreased as the depth increased. The microhardness, which obviously decreased from the surface to the matrix, tended to be equal with the hardness of the matrix after the depth reached 75 microm from the surface.

Conclusion: The thickness of the reaction layer of the improved FUS-invest investment for zirconium-oxide titanium crown and bridge was decreased to 55 microm from 85 microm, which was the thickness before improvement.