title: Fracture and shear bond strength analyses of different dental veneering ceramics to zirconia.
abstract: The purpose of this work was to evaluate the interaction of different layering porcelains with zirconia via shear bond strength test and microscopy. Four different groups of dental veneering porcelains (VM9, Zirkonzanh, Ceramco, IPS) were fused onto forty zirconia-based cylindrical substrates (8mm in diameter and 12 mm in height) (n=10), according to the manufacturer's recommendations. Additionally, layered dental porcelain (D-sign, Ivoclar) was fired on ten Ni-Cr cylindrical substrates Shear bond strength tests of the veneering porcelain to zirconia or Ni-Cr were carried out at a crosshead speed of 0.5mm/min. After the shear bond tests, the interfaces were analyzed by scanning electron microscopy (SEM). The fracture type exhibited by the different systems was also assessed. The results were statistically analyzed by ANOVA at a significant level of p<.05. The shear bond strength values of the porcelain-to-NiCr interfaces (25.3±7.1 MPa) were significantly higher than those recorded for the following porcelain-to-zirconia systems: Zirkonzanh (18.8±1 MPa), Ceramco (18.2±4.7 MPa), and IPS (16±4.5 MPa). However, no significant differences were found in the shear bond strength values between the porcelain-to-NiCr and porcelain (VM9)-to-zirconia (23.2±5.1 MPa) groups (p>.05). All-ceramic interfaces revealed mixed failure type, cohesive in the porcelain and adhesive at the interface. This study demonstrated that all-ceramic systems do not attain yet the same bond strength standards equivalent to metal-ceramic systems. Therefore, despite the esthetic appeal of all-ceramic restorations, the adhesion between the porcelain and zirconia framework is still an issue considering the long term success of the restoration.
authors.affiliation: School of Dentistry (DOD), Division of Prosthodontics, Universidade Federal do Rio Grande do Norte -UFRN, 59056-000, Natal, Brazil.
authors.forename: Alexandre C
authors.initials: AC
authors.lastname: Diniz
authors.affiliation: Materials Engineering Department, Universidade Federal do Rio Grande do Norte - UFRN, Natal, Brazil.
authors.forename: Rubens M
authors.initials: RM
authors.lastname: Nascimento
authors.affiliation: Centre for Mechanics and Materials Technologies - CT2M, Department of Mechanical Engineering (DEM), Universidade do Minho, Campus Azurém, 4800-058, Guimarães, Portugal.
authors.forename: Julio C M
authors.initials: JC
authors.lastname: Souza
authors.affiliation: Materials Engineering Department, Universidade Federal do Rio Grande do Norte - UFRN, Natal, Brazil; Centre for Mechanics and Materials Technologies - CT2M, Department of Mechanical Engineering (DEM), Universidade do Minho, Campus Azurém, 4800-058, Guimarães, Portugal.
authors.forename: Bruno B
authors.initials: BB
authors.lastname: Henriques
authors.affiliation: School of Dentistry (DOD), Division of Prosthodontics, Universidade Federal do Rio Grande do Norte -UFRN, 59056-000, Natal, Brazil. Electronic address: adrianadafonte@hotmail.com.
authors.forename: Adriana F P
authors.initials: AF
authors.lastname: Carreiro
mesh_terms: D000704:Analysis of Variance; D003776:Dental Porcelain / Q000737:chemistry*; D003801:Dental Veneers; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D033081:Shear Strength; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D013696:Temperature; D015040:Zirconium
chemical_list: D003776:Dental Porcelain; D013193:Stainless Steel; D015040:Zirconium; C028541:zirconium oxide
keywords: Dental porcelain; Fracture; Metal-free; Shear test; Zirconia