Abstract
Purpose: Despite their superior physical properties, problems such as breakage have been reported with castable ceramics. The present study investigated the effects of several reinforcement techniques, including the use of bonding materials and porcelain, on the strength of Olympus castable ceramics (OCC) fabricated by electroforming.
Methods: A total of 24 test samples were created, including six 3×4×24 mm samples of each of the following four types: 1) OCC attached to a gold frame (GF) by electroforming (GO); 2) OCC with a porcelain bonding material (GBO), 3) and porcelain (GBPO); 4) and OCC only (O). Reinforcement effects were assessed using a three-point bending test. Additionally, maxillary left central incisor samples were created and subjected to compression testing under the optimum conditions.
Results: The results of the three-point bending test indicated that the average bending strength of GO was significantly higher than that of O, GBO, and GBPO (p<0.05). There were no marked differences among O, GBO, and GBPO. The results of compression testing indicated that the compressive strength of GO crowns was significantly higher than that of OCC crowns (p<0.01).
Conclusion: While bonding material and porcelain did not effectively reinforce OCC, the results of compression testing performed on GO crowns suggested that gold coping by electroforming could serve to reinforce the strength of OCC.
