Shear bond strength of veneering ceramic to electroformed gold with three different surface treatment

Kim, Cheol; Lim, Jang Seop; Jeon, Young Chan; Jeong, Chang Mo; Jeong, Hee Chan

Abstract

PURPOSE
The success of the bonding between electroformed gold and ceramic is dependent on the surface treatment of the pure gold coping. The purpose of this study was to evaluate the bonding strength between the electroformed gold and ceramic with varying surface treatment. MATERIALS AND METHODS: A total of 32 disks, 8 were using conventional ceramometal alloy, 24 were using electroforming technique as recommended by manufacturer, were prepared. 24 electroformed disks were divided 3 groups according to surface treatment, i.e. 50 microns aluminium oxide sandblasting(GES-Sand), gold bonder treatment(GES-Bond) and Rocatec(TM) system(GES-Rocatec). For control group of conventional alloy 50 microns aluminium oxide treatment was done(V-Supragold). Energy dispersive x-ray analysis and scanning electron microscope image were observed. Using universal testing machine, shear bond strength and bonding failure mode at metal-porcelain interface were measured. RESULTS AND CONCLUSION: The following conclusions were drawn: 1. In the energy dispersive x-ray analysis, the Au was main component in electroformed gold(99.9wt%). After surface treatment, a little amount of Al2O3(2.4wt%) were found in GESSand, and SiO2(4wt%) in GES-Bond. In GES-Rocatec, however, a large amount of SiO2(17.4wt%) were found. 2. In the scanning electron microscopy, similar pattern of surface irregu larities were observed in V-Supragold and GES-Sand. In GES-Bond, surface irregularities were increased and globular ceramic particles were observed. In GES-Rocatec, a large amount of silica particles attached to metal surface with increased surface irregularities were observed. 3. The mean shear bond strength values(MPa) in order were 22.9+/-3.7 (V-Supragold), 22.1+/- 3.8(GES-Bond), 20.1+/-2.8(GES-Rocatec) and 13.0+/-1.4 (GES-Sand). There was no significant difference between V-Supragold, GES-Bond, and GES-Rocatec.(p>0.05) 4. Most bonding failures modes were adhesive type in GES-Sand. However, in V-Supragold, GESBond and GES-Rocatec, cohesive and combination failures were commonly observed. From this result, with proper surface treatment method electroformed gold may have enough strength compare to conventional ceramometal alloy.