title: Adhesion to Y-TZP ceramic: study of silica nanofilm coating on the surface of Y-TZP.
abstract: This study evaluated the influence of silica-based film coatings on the surface of yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP), in particular on the durability of the bond strength between the ceramic and resin cement. Eighty Y-TZP (In-Ceram YZ, Vita) blocks (4 × 4 × 3 mm) were obtained and divided into four groups according to the surface treatments (n = 20): tribochemical silica coating (TBS; Cojet, 3M/ESPE), 5 nm SiO2 nanofilm and silanization (F-5), 500 nm SiO2 nanofilm and silanization (F-500), and 500 nm SiO2 nanofilm + hydrofluoric-acid-etching + silanization (F-500HF). Specimens of composite resin (3.25 mm in diameter and 3 mm in height) were cemented to Y-TZP blocks using resin cement (Relyx ARC). Half of the specimens from each group were tested 24 h after adhesion (B: baseline condition), and the other half were subjected to aging (A: storage for 90 days and 10,000 thermal cycles). The specimens were subjected to shear testing (SBS) (1 mm/min). After testing, the surfaces were analyzed with a stereomicroscope and scanning electron microscope. Micromorphologic and elemental chemical analyses of the treated Y-TZP surface were made by X-ray energy dispersive spectroscopy. Bond strength data were statistically analyzed by Kruskal-Wallis/Mann-Whitney tests (α = 0.05). The surface treatment showed significant differences for B (p = 0.0001) and A (p = 0.0000) conditions. In both storage conditions, TBS and F-5 groups promoted the significantly highest bond strength. Most of the specimens presented adhesive failure. The X-ray energy dispersive spectroscopy analysis depicted the highest peak of silica in the TBS, F-5, and F-500 groups. The adhesion to zirconia can be improved if the surface receives a 5 nm layer of SiO2 nanofilm or is subjected to sandblasting with silica particles, followed by silanization.
authors.affiliation: Faculty of Odontology, Federal University of Santa Maria, Santa Maria, Brazil.
authors.forename: Carolina Ceolin
authors.initials: CC
authors.lastname: Druck
authors.forename: João Luiz
authors.initials: JL
authors.lastname: Pozzobon
authors.forename: Gustavo Luiz
authors.initials: GL
authors.lastname: Callegari
authors.forename: Lucio Strazzabosco
authors.initials: LS
authors.lastname: Dorneles
authors.forename: Luiz Felipe
authors.initials: LF
authors.lastname: Valandro
mesh_terms: D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D015019:Yttrium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D020099:Coated Materials, Biocompatible; C499362:yttria stabilized tetragonal zirconia; D015019:Yttrium; D012822:Silicon Dioxide; D015040:Zirconium
keywords: adhesion; nanofilm; silica deposition; zirconia