Effect of Gold Coating on Interfacial Reaction between Dental Porcelain and Titanium

Abstract

Cross-sectional microstructure observation of the titanium firing porcelain inserted ion-coated gold layer was performed by SEM-EDX that can analyze light elements from boron. Two gold-coated samples applied to mirror finished titanium surface were prepared; one was applied only degassing treatment, and the other was applied firing after degassing treatment. In addition, in order to investigate effect of the gold coating, titanium/porcelain samples without coating were also observed. From SEM-EDX observation of the specimen, approximately 2.5 mm thickness titanium oxide layer appeared across the gold film in the first sample. In the titanium firing porcelain after degassing treatment, two obvious reaction layers appeared across the gold coating. One included mainly titanium and oxygen, and another included titanium, gold and aluminum. Thickness of the reaction layers was approximately 2.5-3 mm. From the results, it is suggested titanium was diffused into porcelain through a gold coating, and titanium oxide was formed at an interface. Titanium/porcelain without gold coating had two reaction layers at the interface, however, many cracks and crevices were exhibited in the layer and between the layers. Effect of gold coating on interfacial layer formation was discussed by the comparison with titanium/porcelain interface without gold coating. Thickness of the reaction layers decreased by gold coating, and cracks and crevices in the layer disappeared. The results suggested that oxygen diffusion became lower due to existence of the coating, and titanium-gold reaction changed layer's microstructure. It is also suggested that gold diffusion into the reaction layer and restriction of oxygen diffusion contribute to the reaction layer formation, consequently gold coating on titanium substrate contributes to improvement of adhesion between titanium and porcelain.

Exfoliation Resistance, Microstructure, and Oxide Formation Mechanisms of the White Oxide Layer on CP Ti and Ti–Nb–Ta–Zr Alloys

“…As shown in Figure 8 b, the Au marker insertion was distinguished by a thin bright line, which clearly differentiated between the Ti substrate and the oxide layer. This result is in good agreement with the results of degassing treatments on Ti with an Au marker [ 17 , 19 ]. In addition, the Au marker showed that the oxide layer growth was drastically suppressed.…”

“…The Au marker method determines the major atomic migration direction via the insertion of a marker consisting of a nonreactive material that has little effect on the oxidation reaction itself. Since Au is hardly oxidized and has little reaction with Ti, Miura et al used this method to clarify the reaction during Ti/porcelain firing [ 16 , 17 ]. It was discovered that the reaction layer formed on the porcelain side of the Au marker, and they concluded that Ti diffused into the porcelain [ 16 , 17 ].…”

“…Since Au is hardly oxidized and has little reaction with Ti, Miura et al used this method to clarify the reaction during Ti/porcelain firing [ 16 , 17 ]. It was discovered that the reaction layer formed on the porcelain side of the Au marker, and they concluded that Ti diffused into the porcelain [ 16 , 17 ]. We conducted similar experiments with CP Ti, Ti–29Nb–13Ta–4.6Zr, and Ti–36Nb–2Ta–3Zr–0.3O.…”

Improvement in Dental Porcelain Bonding to Milled, Noncast Titanium Surfaces by Gold Sputter Coating

“…Recent reports have used gold sputter coating on cast pure Ti to increase the adhesion of porcelain to Ti surfaces . In these studies, a sputter coater was used to produce a gold coating layer of 0.3 to 2 μm on the cast Ti surface following approximately 15 minutes of coating treatment, and then the adhesion morphology of the cast Ti/porcelain was evaluated qualitatively.…”

Fabrication of TiO₂/SiO₂ Composite Coating via a High-Temperature Self-Organizing Microporous TiO₂ Layer on Ti

“…However, they are inferior from an esthetic point of view. For example, a ceramic-fused metallic core crown is commonly used to cover the core s metallic color; however, exfoliation of the ceramic surface from the metallic core is a serious clinical problem in dentistry 1,2) . Thus, in the eld of dental prostheses, discoveries of white-colored materials with high ductility, high strength, and excellent aesthetic properties are quite highly desired.…”