AN INVESTIGATION OF DEBONDING BETWEEN HEAT CURED PMMA AND TITANIUM-ALLOY (TI-6AL-4V)

Objectives: The bonding: of acrylic resin to dental prostheses constru cted from metal has been the subject of extensive research in recent y ears, much of it between base-metal alloys such as Ni-Cr alloys and de ntal composite. The development of techniques for the manufacture of d ental appliances from titanium and titanium alloys has opened new aven ues for investigation of the metal/acrylic resin bond. Methods: In thi s study: a bond strength comparison between two PMMA products, Trevalo n and Metadent, and discs of titanium alloy, Ti-6Al-4V, was investigat ed using a four-point bend test configuration. Trevalon is a standard, commercially available, heat-cured acrylic resin, while Metadent is a n acrylic resin incorporating a chemical bonding agent, 4-META. A comp arison was made between two processes that are routinely used to enhan ce the bond between metal and acrylic, namely sandblasting of the meta l surface and using the Silicoater system following sandblasting. Each of the samples was paired, thus allowing a further comparison to be m ade between samples that had undergone thermocycling in a water bath; with those that had been held at a constant temperature. Results: The study revealed that a superior metal/acrylic bond was achieved by the use of the silicoating system when either Trevalon or Metadent was use d both before and after thermocycling. Reduced debonding loads were re corded for all samples that had undergone thermocycling. Conclusions: Highest bond strengths were recorded for Trevalon or Metadent processe d against a silicoated Ti-alloy surface. (C) 1997 Elsevier Science Ltd .