Bond strength of binary titanium alloys to porcelain

The purpose of this study was to investigate the bond strength between porcelain and experimental cast titanium alloys. Eleven binary titanium alloys were examined: Ti–Cr (15, 20, 25 wt%), Ti–Pd (15, 20, 25 wt%), Ti–Ag (10, 15, 20 wt%), and Ti–Cu (5, 10 wt%). As controls, the bond strengths for commercially pure titanium (KS-50, Kobelco, Japan) and a high noble gold alloy (KIK, Ishifuku, Japan) were also examined. Castings were made using a centrifugal casting unit (Ticast Super R, Selec Co., Japan). Commercial porcelain for titanium (TITAN, Noritake, Japan) was applied to cast specimens. The bond strengths were evaluated using a three-point bend test according to ISO 9693. Since the elastic modulus value is needed to evaluate the bond strength, the modulus was measured for each alloy using a three-point bend test. Results were analyzed using one-way ANOVA/S-N–K test (α=0.05). Although the elastic moduli of the Ti–Pd alloys were significantly lower than those of other alloys (p=0.0001), there was a significant difference in bond strength only between the Ti–25Pd and Ti–15Ag alloys (p=0.009). The strengths determined for all the experimental alloys ranged from 29.4 to 37.2 MPa, which are above the minimum value required by the ISO specification (25 MPa).