Repair of heat treated composites is made difficult due to the diminished number of unreacted methacrylate groups available. Drs. Lucena-Martin, Gonzalez-Lopez, and Navajas-Rodriguez de Mondelo (J Prosth Dent 2001:86:481-8) tried various combinations of air abrasion, phosphoric acid, hydrofluoric acid, acetone, Special Bond II, Heliobond, and Prime and Bond 2.0 on aged samples of Herculite VRV and Heliomolar Radiopaque specimens.

The results showed the greatest shear force was obtained with air abrasion and Prime and Bond II for both composites tested. It would seem that air abrasion is critical in gaining a high bond strength between laboratory manufactured composites and intraoral repair materials. This bond is apparently mechanical not chemical.

Herculite Hydroflouric	Air Abrasion	Heliomolar Hydroflouric	Air Abrasion