Experimental and finite element study of residual thermal stresses in veneered Y-TZP structures. Issue 7 (15th May 2016)

• Record Type: Journal Article
• Authors: Tanaka, Carina B.; Harisha, Hossam; Baldassarri, Marta; Wolff, Mark S.; Tong, Hui; Meira, Josete B.C.; Zhang, Yu
• Is Part Of: Ceramics international. Volume 42:Issue 7(2016)
• Page Start: 9214
• Page End: 9221
• Publication Date: 2016-05-15
• Subjects: Porcelain-veneered zirconia -- Residual thermal stresses -- Cooling rates -- Specimen geometries -- Vickers indentation method -- Finite element analysis; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2016.03.018
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: The main complications of zirconia-based laminated systems are chipping and delamination of veneering porcelain, which has been found to be directly associated with the development of residual thermal stresses in the porcelain layer. This study investigates the effects of cooling rate and specimen geometry on the residual stress states in porcelain-veneered zirconia structures. Bilayers of three different shapes (bars, semi-cylindrical shells, and arch-cubic structures) with 1.5 mm and 0.7 mm thickness of dentin porcelain and zirconia framework, respectively, were subjected to two cooling protocols: slow cooling (SC) at 32 °C/min and extremely-slow cooling (XSC) at 2 °C/min. The residual thermal stresses were determined using the Vickers indentation method and validated by finite element analysis. The residual stress profiles were similar among geometries in the same cooling protocol. XSC groups presented significantly higher tensile stresses ( p =0.000), especially for curved interfaces. XSC is a time-consuming process that showed no beneficial effect regarding residual stresses compared to the manufacturer recommended slow cooling rate.