Influence of water, loading rate and bonder on the adhesion of porcelain to titanium

Objectives The aim of this study was to measure the influence of water on the adhesion between titanium and porcelain by means of the strain energy release rate (G-value or interfacial toughness). Methods Rectangular specimens of grade II titanium and a reference gold–palladium porcelain fused to metal (PFM) alloy were veneered with feldspathic porcelains. In the case of the titanium, two gold and one ceramic bonder systems were used to enhance the adhesion of the porcelain. The G-value was measured with a four-point bending configuration developed by Charalambides et al. (Journal of Applied Mechanics (Trans ASME). 1989;56:77–82), at four different loading rates (from 0.1 to 15 N/s) in water and at one loading rate (1.5 N/s) in kerosine. Results There was a significant difference (ANOVA, p < 0.01) in the interfacial toughness between the different bonding systems, with the two goldbonder systems exhibiting higher toughness in kerosine and water than the ceramic bonder. The two goldbonders achieved the best results across all loading rates. Their interfacial toughness, tested in kerosine, varied between 45.83 ± 6.72 and 73.54 ± 17.01 J/m2 and tested in water from 40.86 ± 2.23 to 69.17 ± 12.33 J/m2, respectively. The ceramic Ti bonder achieved the lowest G-values throughout (30.15 ± 5.52 J/m2 in kerosine to 11.08 ± 2.18 J/m2 in water). The gold–palladium PFM alloy showed more constant behaviour (33.48 ± 2.24 J/m2 to 23.07 ± 0.53 J/m2 in kerosine and water, respectively). Conclusion Compared to the gold–palladium PFM alloy, the goldbonders achieved much higher G-values whereas the ceramic Ti bonder G-values were lower when tested in water and in kerosine.