SEM/EDS evaluation of porcelain adherence to gold‐coated cast titanium

Abstract

The adhesion between titanium and dental porcelain is related to the diffusion of oxygen to the reaction layer formed on cast-titanium surfaces during porcelain firing. The diffusion of oxygen could be suppressed by coating the titanium surface with a thin gold layer. This study characterized the effects of gold coating on titanium-ceramic adhesion. ASTM grade II CP titanium was cast into a MgO-based investment (Selevest CB, Selec). The specimen surfaces were air abraded with 110-microm Al(2)O(3) particles. Gold coating was applied on titanium surfaces by three methods: gold-paste (Deck Gold NF, Degussa-Ney) coating and firing at 800 degrees C for three times, single gold-paste coating and firing followed by sputter coating (40 mA, 500 s), and sputter coating (40 mA, 1000 s). Surfaces only air abraded with Al(2)O(3) particles were used as controls. An ultra-low-fusing dental porcelain (Vita Titankeramik, Vident) was fused on titanium surfaces. Specimen surfaces were characterized by SEM/EDS and XRD. The titanium-ceramic adhesion was evaluated by a biaxial flexure test (N = 8), and area fraction of adherent porcelain (AFAP) was determined by EDS. Numerical results were statistically analyzed by one-way ANOVA and the Student-Newman-Keuls test at alpha = 0.05. SEM fractography showed a substantial amount of porcelains remaining on the gold-sputter-coated titanium surfaces. A new Au(2)Ti phase was found on gold-coated titanium surface after the firing. Significantly higher (p <.05) AFAP values were determined for the gold-sputter-coated specimens compared to the others. No significant differences were found among the other groups and the control. Results suggested that gold coatings used in this study are not effective barriers to completely protect titanium from oxidation during the porcelain firing, and porcelain adherence to cast titanium can be improved by gold-sputter coating used in the present study.

Influence of chromium interlayer on the adhesion of porcelain to machined titanium as determined by the strain energy release rate

“…5 In general, the interfacial strain energy release rate determined in this study showed that the CP Ti/Vita Titankeramik (0.5 h 5% (w/v), 1 h 5% (w/v) and 0.5 h 10% (w/v)) groups provided the highest G-value amongst the other Vita Titankeramik groups. This finding was supported by the SEM images of the peeled titanium surface which showed that the mode of failure was mixed for these groups (Fig.…”

“…4 A number of surface modification methods to improve oxidation properties of titanium to overcome this problem have been proposed such as gold coating and silicon nitride coating. 5,6 Various tests have been designed and selected by researchers to evaluate metal-ceramic bond strengths. 7 However, most of the bond tests are associated with stress gradients along the interfacial regions and stress concentration effects.…”

Effect of Oxidation and SiO2 Coating on the Bonding Strength of Ti-Porcelain

“…The use of Si 3 N 4 , chrome, SiO 2 , and TiO 2 as intermediate layers to minimize Ti oxidation for Ti-porcelain restorations has been investigated ( Ref 4,[8][9][10][11][12][13][14].…”

A Review of Pathological Biomineral Analysis Techniques and Classification Schemes

“…SEM produces images of high resolution, which means that closely spaced features can be examined at a high magnification (Harada et al, 1993). Preparation of sample is relatively easy since most SEMs only require the sample to be conductive (Lee et al, 2004). The spatial distribution of major and trace elements can be studied in a range of human kidney and bladder stones with well-documented histories to understand their initiation and formation…”