EVALUATION OF 3 SILICOATING METHODS FOR RESIN-BONDED PROSTHESES

Three different methods of increasing the bond strength of resin to me tal were tested: the original Silicoater technique, the Silicoater MD technique, and the Rocatec system. Metals used for the resin-bonded pr ostheses were gold, a cobalt-chromium (Co-Cr) alloy, and titanium. Sil icoating increased the bond strength to sandblasted specimens. The ori ginal Silicoater technique produced the highest bond strengths, especi ally when used with the Co-Cr alloy and titanium. The Silicoater MD te chnique showed the lowest bond strengths for all of the test metals. S torage for 7 days with protective film on the silicoated surface did n ot affect the bond strength, as compared with specimens bonded immedia tely. The retention of the resin to the gold specimens (Rocatec system ) decreased after thermocycling, but retention to the Co-Cr alloy and titanium was not affected. Various resin cements were tested and showe d the same retention with the exception of Microfill Pontic, which gav e a weaker bond. Scanning electron microscope (SEM) and energy-dispers ive X-ray analysis (EDAX) of the specimens before and after the measur ements gave no clear explanation of the differences in bond strengths between the test metals. However, it was concluded that silicoating of the metal surfaces contributed to the retention of the resin by chemi cal action, as no differences in adaptation of the resin to the metal were seen between specimens pretreated by sandblasting and those which were also silicoated.