Effect Of Sputtering Gold Coating On The Bonding Strength Of Titanium And Two Low-fusing Porcelains

ObjectiveThis experiment aimed to study the effect of sputtering gold coating on the forged CP(commercial pure) titanium on the bonding strength of titanium and two low-fusing porcelains, in order to search a effective method to enhance the bonding strength between titanium and porcelain.Materials and MethodsIn accordance with the requirement of ISO 9693 standard, forged CP titanium plate was cut into standard titanium plate (25.0 mm x 3.0 mm x 0.5 mm). After silicon carbide abrasion and 100 microns of alumina particle sandblasting, the titanium strips are cleaned with steam and supersonic clean.According to whether sputtering coating of gold (Au) and the kinds of sintering ceramic powder (SP:Super Porcelain Ti-22、TC:Triceram), the titanium strips are divided into four groups:Sand blasting+sintering SP porcelain group (group SP); sand blasting+ sputtering gold coating+sintering SP porcelain group (group AuSP); sand blasting+ sintering TC porcelain group (group TC), sand blasting+sputtering gold coating+sintering TC porcelain group (group AuTC). A layer of porcelain was built up onto the titanium plates of all groups with a conventional technique.Three point bending test are used to calculate the titanium -porcelain bending strength, stereoscopic microscope are applied to characterize the titanium strips after three point bending test and determine the titanium-porcelain fracture mode. All the data was calculated for statistical analysis. Field Emission Scanning Electron Microscope (FE-SEM) was used to observe the titanium-porcelain interface, Electron Microprobe (EMP) was used to analysis the element change in the interface.ResultsIndependent sample t test showed the bonding strength of SP group (28.91±3.80 MPa) had no statistical significance difference with TC group (28.02±1.33MPa) (P=0.540), while the bonding strength of AuSP (36.32±1.36 MPa) was much higher than the AuTC group (27.90±1.49 MPa) (P<0.000). The bonding strength of AuSP and SP group were 36.3±1.36 MPa and 28.91±3.80 MPa, which showed significant statistical difference (P<0.000), AuTR and TR group were 28.02±1.33 MPa and 27.90±1.49 MPa, the two groups had no statistical significance (^=0.876).The SP, AuTC and TC groups showed predominately adhesive fracture at the titanium oxidation, whereas the failure modes of AuTC group were cohesive and adhesive, mainly cohesive.FE-SEM showed Cracks and bubbles in the interface of SP and TR group, while no visible cracks and bubbles could be detected in the gold coating group. FE-SEM with EMP illustrated good suppressing effect of gold coating on the infiltration of titanium and oxygen in the interface.ConclusionsSputtering gold intermediate coatings on the CP titanium could effectively suppress the infiltration of titanium and oxygen in the interface in both SP and TC powder.Gold coating could change the fracture mode and improve the bonding strength of SP powder, however it had no effect to the TC powder. This may have some potential for dental applications.