Durability of resin bonds to pure titanium

This study evaluated the bond strength and bond durability of new adhesive systems to pure titanium.

Plexiglass tubes filled with composite were bonded to titanium discs. Groups of 24 samples were bonded using six different bonding systems. Subgroups of eight bonded samples were stored in an isotonic artificial saliva solution (37 degrees C) for 1, 30, or 150 days. In addition, the 30- and 150-day samples were thermal cycled for 7,500 or 37,500 cycles between 5 degrees C and 55 degrees C, respectively. After these storage conditions, all samples were debonded in tension.

The bond strength of a conventional bisphenol-A glycidyl methacrylate composite to sandblasted titanium was significantly lower than using chemomechanical bonding systems and decreased slightly during the storage time of 150 days. The additional use of a silane on sandblasted titanium resulted in an insignificant increase in bond strength and decreased over storage time to the same level as on sandblasted-only titanium. Statistically significant higher bond strengths were achieved either with the combination of silica coating and use of a conventional bisphenol-A glycidyl methacrylate composite or with the combination of sandblasting and the use of composites modified with a phosphate monomer. In the latter systems, the bond strengths were only limited by the cohesive strength of the composite resins. A new phosphate monomer containing composite showed a tendency to lose cohesive strength over time (statistically not significant).

Using chemomechanical bonding systems, ie, silica-coating systems or modified composites with adhesive monomers, resulted in 2 to 2.5 times increased bond strength to titanium compared with the bond strength of a conventional bisphenol-A glycidyl methacrylate composite. With chemomechanical bonding systems, the resin bond to titanium was durable over 150 days, even after being stored in water and thermal cycled.