An Investigation of Debonding Between Heat-cured PMMA and Titanium Alloy (Ti-6A1-4V)

Objectives: The bonding of acrylic resin to dental prostheses constructed from metal has been the subject of extensive research in recent years, much of it between base-metal alloys such as Ni-Cr alloys and dental composite. The development of techniques for the manufacture of dental appliances from titanium and titanium alloys has opened new avenues for investigation of the metal/acrylic resin bond.

Methods: In this study, a bond strength comparison between two PMMA products, Trevalon and Metadent, and discs of titanium alloy, Ti-6A1-4V, was investigated using a four-point bend test configuration. Trevalon is a standard, commercially available, heat-cured acrylic resin, while Metadent is an acrylic resin incorporating a chemical bonding agent, 4-META. A comparison was made between two processes that are routinely used to enhance the bond between metal and acrylic, namely sandblasting of the metal surface and using the Silicoater system following sandblasting. Each of the samples was paired, thus allowing a further comparison to be made 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 used both before and after thermocycling. Reduced debonding loads were recorded for all samples that had undergone thermocycling.

Conclusions: Highest bond strengths were recorded for Trevalon or Metadent processed against a silicoated Ti-alloy surface.