Effect of convergence angle and luting agent on the fracture strength of In ceram crowns
- Cite this article as:
- Correr Sobrinho, L., Consani, S. & Knowles, J.C. Journal of Materials Science: Materials in Medicine (1999) 10: 493. doi:10.1023/A:1008905210614
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This study compared the fracture strength of In ceram crown shapes fabricated with either 8 or 16° total occlusal convergence; and attached with either a commercial zinc phosphate cement or a glass ionomer cement. Thirty crown shapes (8 mm diameter and 8.5 mm high) were fabricated for each preparation design on a brass master die with approximately the same dimensions as a premolar. In ceram crown shapes were luted on to the die using zinc phosphate or glass ionomer. The crown shapes were fractured in a testing machine (Instron) using a steel ball, 4 mm in diameter, that contacted the occlusal surface and the resulting data were statistically analyzed using a Mann–Whitney test. The results indicate that there is no statistical difference in the fracture strength values between preparations with 8° total convergence compared with 16° using the same cement. However, crown shapes luted with zinc phosphate on preparations with 8 and 16° total occlusal convergence were significantly stronger than those luted using glass ionomer cements plt; 0.05).