Bonding of dental porcelain to non-cast titanium with different surface treatments

Abstract

INTRODUCTIONTitanium (Ti) tends to react with oxygen at high temperatures, which results in an overly thick oxidization layer. The oxidization layer is located on the Ti surface and influences the bond strength of the Ti-porcelain prosthetic appliance 1,2) . It has been reported that dental porcelain-fused-to-metal (PFM) crowns can be produced with a thinner interfacial oxide layer that effectively promotes the bond between metal and porcelain 3) . Thus, several manufacturers have produced low-fusing dental porcelain that is suitable for sintering onto the Ti surfaces with thinner oxide layers 4) . However, the bond strength between low-temperature porcelain and Ti is only slightly higher than the minimum metal-porcelain bond strength prescribed by ISO 9693 5) . Relevant literature shows that the Ti-porcelain bond strength is still lower than the bond strength between porcelain and other noble or base metals 6,7) . Consequently, there is a need for further investigation to improve the Ti-porcelain bond strength, which may be applicable to PFM dental crowns for long-term clinical application.The strength of the bond between metal and porcelain can be influenced by several factors, including the metal and porcelain chemical compositions, metal surface treatment, porcelain sintering procedure and test method 8) . The bond strength primarily depends on the mechanical and chemical properties of the interface between the metal and porcelain 9,10) . Although extensive studies have employed different surface treatments of Ti prior to porcelain sintering [11][12][13][14][15][16][17][18][19] , a simple and practical technique to improve Ti-porcelain bond strength has not been well determined, and the underlying mechanism for the bonding of Ti and porcelain is not well understood.Chemical solution treatment is a method that can be used to treat and clean metallic surfaces for clinical applications 20) . In industrial fields, an alkaline or acid solution has been successfully employed to clear superficial pollutants from Ti and Ti alloys 21) . Diniz et al. 22) indicated that hydrofluoric acid can serve as an improvement agent and etchant of Ti, thus allowing a higher-quality metallic surface and the removal of pollutants produced during manufacturing. A previous study showed that the Ti surface hardness increases after immersion in a mixed nitric acid/hydrofluoric acid solution such that the Ti-porcelain bond strength is improved 23) . Reyes et al. 8) found that the bonding of Ti and porcelain can be improved by immersing the Ti in hydrochloric acid prior to porcelain sintering. Tróia et al. 12) studied the bond strength between porcelain and cast Ti with different surface chemical treatments. The Ti surface is immersed in acid solution, treated (or not treated) with alkaline solution, and finally sandblasted prior to porcelain sintering. There is no improvement in the Ti-porcelain bond strength when the Ti surface is only immersed in acid solution. The bond strength is enhanced when the Ti surface is first treated w...

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

“…Specimen preparation before gold sputter coating treatments was conducted in the same way as our previous report, as described below. Commercially available noncast pure Ti (grade 2) strips were used as test specimens.…”

“…In accordance with ISO 9693, a low‐fusing porcelain (Titankeramik; Vita Zahnfabrik, Bad Säckingen, Germany) plate (8.0 ± 0.1 × 3.0 ± 0.1 × 1.0 ± 0.1 mm 3 ) was sintered to the center of each Ti strip. In accordance with the manufacturer‐recommended sintering conditions (Table ), we employed the same porcelain sintering procedure as used in our previous report . An opaque porcelain with a thickness of approximately 0.2 mm was sintered onto the Ti strips.…”

“…Bond strength of Ti/porcelain specimens was measured using the same methods outlined in our previous report . In brief, a universal test machine (EZ‐L; Shimadzu, Tokyo, Japan) was used for three‐point bending tests of Ti/porcelain strip specimens in accordance with ISO 9693 .…”

“…In addition, no previous studies have proposed simple, practical techniques to improve the bond strength between noncast, milled Ti and dental porcelain. In a previous study, the authors of this report used similar testing methods to investigate the porcelain bonding to Ti surfaces treated by combining the mechanical sandblasting and different chemical etching processes. In this study, our hypothesis is that gold sputter coating can improve the bond strength between Ti and porcelain.…”

Influence of ultraviolet irradiation treatment on porcelain bond strength of titanium surfaces

“…Enhanced mechanical fitting and chemical bonding force by sandblasting with silica (Si) has been the subject of various experiments 5) . Furthermore, acid etching of the Ti surface to improve bond strength through better wettability 6,7) as well as the combination of sandblasting and acid treatment 8) have been investigated. These methods focused on Ti surface modification in parallel with examination of the strength of bonding with porcelain; however, they have not been applied in clinical practice.…”