Journal of Dental Research, Vol 69, 1230-1235, Copyright © 1990 by International & American Associations for Dental Research Online Journals
Oxide adherence and porcelain bonding to titanium and Ti-6Al-4V alloy
M. Adachi, J. R. Mackert Jr, E. E. Parry and C. W. Fairhurst
Division of Dental Materials, School of Dentistry, Medical College of Georgia, Augusta 30912-1264.
The bonding of an experimental low-fusing porcelain to titanium and
Ti-6Al-4V was evaluated by an x-ray spectrometric technique that measures
the area that remains covered with porcelain following a controlled
deformation of the metallic substrate. Oxide adherence strength values for
titanium and Ti-6Al-4V oxidized at 750 degrees and 1000 degrees C were
measured in tension with use of high-strength adhesives. The effect of
further oxidation that would occur during porcelain firing was evaluated
via simulated porcelain firings without actual porcelain application.
Interface cross-sections of the titanium-porcelain and Ti-6Al-4V-porcelain
bonds were examined in a scanning electron microscope (SEM). The porcelain
was found to delaminate completely from the metal substrate, leaving less
than 1% of the surface covered with porcelain. The oxide adherence of the
specimens oxidized at 750 degrees C was good, but those oxidized at 1000
degrees C exhibited significantly lower oxide adherence (p = 0.001). The
simulated porcelain-firing oxidation treatments also produced a significant
decrease in oxide adherence (p = 0.004). The 750 degrees C oxidation
treatments produced oxide films too thin to be visualized in the SEM,
whereas the 1000 degrees C oxidation treatments produced oxide films
approximately 1 micron thick. The lower oxide adherence of the
1-micron-thick oxide films is consistent with reports in the titanium
literature of oxide delamination when the oxide film reaches 1 micron in
thickness.
