Abstract:

Objective:Sufficient porcelain-titanium bond is a vital factor determining the clinical performance of titanium-porcelain restorations. The purpose of this studywas to investigate the effects of self-preparation La-porcelain composition on the porcelain-ti- tanium bonding strength and to compare with the Vita Titankeramik.Methods:The present study examines 5 different recipes of porcelain by weight%:SiO2,12%~17%;LaO2,7%~10%;Al2O3,9%~14%;B2O3,23%~31%;CaO,6%~8%;K2O,2% ~3%;SrO,2%~4%;Na2O, 1%~3%; SnO2, 8%~10%;ZrO2,3%~5%;TiO2,6%~8%. Specimens were tested in push type shearwith a universal testingmachine. Scanning electronmicroscopy (SEM) and electron probe microanalyzer (EPMA) were employed to reveal the microstructures and diffusion of elements in the interfacial regions between the porcelain coating and ti- tanium to the bond strength when fired at 800e.Results:The ratios of crystallized compositions had significant influences on the porcelain-titanium bond strength (P<0.05). La-porcelain had the highest shear bond strength (37.76 MPa). The shear bond strength of the Vita Titankeramik to titanium was 20.18 MPa. The results of SEM revealed integrity of porcelain-titanium joints in La-porcelain and a greater amount of porosity in the interface of Vita Titankeramik to titanium. EPMA analysis demonstrated the aggregation of Si and Sn in the interfacial regions and their diffusion into the titanium.Conclusion:Chemical compositions of porcelain and ratios of crystallized compositions play the important role in the titanium porcelain bond. La-porcelain had the highest shear bond strength and good porcelain-titanium joints. La-porcelain is a new-style low fusing porcelain/titanium system.

Key words: titanium, dental porcelain, titanium-porcelain interface