2004 Volume 24 Issue 2 Pages 172-178
Titanium is equipped with desirable properties as a dental metal owing to its superior corrosion resistance and bio-affinity and to similar mechanical properties to the type IV gold alloy. It is pointed out, however, that titanium is difficult to cast because of its high melting point and high chemical activities at high temperatures and to polish due to its high hardness. Although the dental CAD/CAM system is being used for manufacturing prosthetic dental crowns rationally and precisely, a problem still remains as to the fitting accuracy of prosthetic titanium crowns. In the present study, we thus enlarged the cutting passes determined from the data obtained by using a pattern model by 0.3%, 0.5% and 1.0% along the X-, Y-and Z-axes, and comparatively investigated the inner surface fitness of titanium crowns. As a result, the cement capsules of the pure titanium crowns manufactured at 1.0% enlargement of cutting pass had a thickness of 51.6 ±28.1, um (mean ±SD) at their margins and a thickness of 35.9±14.7 pm throughout the inner surface. These results suggest that the pure titanium crowns manufactured by 1.0% enlargement of the cutting pass can be applied clinically.
