Main

Loomans BA, Mesko ME et al. J Dent 2017;59: 18–25

Hydrofluoric acid, air abrasion and silane coupling agents have been used singly and in combination to facilitate the bond between fractured and repaired resin composite restorations. This in vitro study explored mechanical properties associated with repairing indirect composites (3M™ ESPE™ Lava™ Ultimate CAD/CAM Restorative and Clearfil ESTENIA™ C&B) with Filtek Supreme XTE. Composite blocks were roughened, mimicking that achieved with a diamond bur. They were then treated with combinations of air abrasion (silanised silica-coated 30 μm aluminium oxide particles), delivered using different units, and hydrofluoric acid. The key finding was that when the repaired resin composite materials were subjected to thermal cycling, thermal cycling was both detrimental to the cohesive strength of the materials and the repair bond strengths. However, without cycling, such treatments resulted in a significant increase of bond strength, but for LAVA™ Ultimate only. Just as for indirect composite restorations, no surface treatments are universally applicable for repair of direct composite materials.