Bond characteristics of porcelain fused to milled titanium

Objectives. A bonding agent has recently been introduced that prepares the surface of milled titanium copings for bonding to low fusing dental porcelains. This study evaluated the effectiveness of the bonding agent by comparing the shear and three-point bending strength of specimens made with three combinations of materials: 1) milled titanium/porcelain with bonding agent, 2) the same milled titanium/porcelain without bonding agent, and 3) cast high palladium/conventional porcelain. Methods. Shear specimens consisting of porcelain cylinders 6 mm in diameter and 8 mm in length were fired to the ends of metal cylinders 6 mm in diameter and 13 mm in length. Three-point bend specimens made of 25 × 3 × 0.5 mm metal bars were veneered with 8 × 3 × 1 mm of porcelain in the bar's center. Specimens were tested in shear and bending in a universal testing machine. The data were analyzed using one-way ANOVA and Newman-Kuels post hoc tests (p = 0.05). Results. When a titanium bonding agent was used, porcelain to titanium bond strength was slightly but statistically significantly greater than the porcelain to high palladium bond strength. The result was the same when measured by both shear and three-point bending tests. Without the bonding agent, the shear strength of porcelain to titanium was significantly lower than that of the bonding agent and high palladium groups. Significance. The use of a bonding agent improves the bond strength of porcelain-fused-to-milled titanium.