Enhancement of resin bonding to heat-cured composite resin

The purpose of this study was to evaluate the effectiveness of various surface treatments used to enhance the bond strength of resin cements to two different laboratory-processed composite resins. Seventy specimens of a microfilled composite resin (Concept) and 70 specimens of a micro-hybrid composite resin (Herculite XRV) were fabricated in metal wells and subjected to heat (250 degrees F) and pressure (85 psi) curing. An additional 70 specimens of each material were fabricated in the shape of disks and also subjected to the same heat/pressure curing. All composite resins were subjected to one of seven treatment regimens. The like-treated specimens were then bonded together using dual-curing resin cement and a uniform seating force (106 gm). After 7 days, bonded specimens were thermocycled 1000 times at 5 and 55 degrees C, and debond shear strengths were determined on a Universal Testing Machine. The use of microabrasion (50 microns aluminum oxide at 60 psi) and ceramic layer deposition (30 microns aluminum oxide with a ceramic additive at 75 psi) consistently improved the shear bond strength of the resin cements to both composite resins. The other treatment combinations provided varying effects. In conclusion, microabrasion or ceramic layer deposition are preferred methods to enhance the bond of resin cements to composite resins.