Abstract
Purpose: Electroformed coping has a high adaptability and biocompatibility. Olympus Castable Ceramics (OCC), which is applied on castings using the lost wax technique, resembles tooth substance and also is biocompatible. Prior to developing new crown restorations using these characteristics to obtain a reinforced mechanical interlocking force between the sandblast gold frame and OCC, the effect of different thicknesses of reinforcement was analyzed using the coping fabricated by Galvano forming.
Methods: To evaluate interlocking force, the reinforced effect of OCC was examined for three thicknesses of gold frame: 150, 250 and 350 μm, which were then compared with the value of single OCC.
Results: In the three-point flexural strength test, only the sandblasted and 250-μm gold frame specimen showed a significant high value. Observing and analyzing the fractured and exfoliated surface, the sandblasted gold foil surface showed a rough texture which easily exerts an interlocking force but no chemical bonding effect.
Conclusion: Chemical bonding could not be expected and mechanical surface treatment of the gold frame is essential for reinforcement for both materials. The sandblasted 250-μm thick gold frame proved to be the most effective.
