抄録
According to the recent studies, titanium and zirconium, the refining method of which was recently found by W. J. Kroll, seem to be hopeful for dental use on account of their excellent mechanical properties and resistance to corrosion. So the authors intended to study the application of these metals for dental use.
Corrosion resistance of titanium, zirconium, Ni-Cr alloy and 18-8 steel are described in this report. Ni-Cr alloy and 18-8 steel are used in this country as the substitutive metal for dental gold alloys. Titanium and zirconium showed a strong resistance to corrosion by 1% NaCl, 0.05% HCl, 1% lactic acid and 0.1% Na2S, however Ni-Cr alloy and 18-8 steel were corroded in some cases (Table 1) . Titanium and zirconium did not lose their metallic brightness against 1% acids and zirconium was most resistant to corrosion by 50% acids (Table 2) . From these facts it could be concluded that titanium and zirconium were better dental materials with respect to corrosion resistance.
