title: Influence of contamination on bonding to zirconia ceramic.
abstract: The purpose of this study was to investigate the influences of contaminations and cleaning methods on bonding to dental zirconia ceramic. After saliva immersion and using silicone disclosing agent, airborne-particle abraded ceramic specimens were cleaned with isopropanol (AL), acetone (AC), 37% phosphoric acid (PA), additional airborne-particle abrasion (AA), or only with water rinsing (SS). Airborne-particle abraded specimens without contaminations (CL) were used as control group. For chemical analysis specimens of all groups were examined with X-ray photoelectron spectroscopy (XPS). Plexiglas tubes filled with composite resin were bonded to ceramic specimens using a phosphate-monomer containing composite luting resin. After 3-day water storage, tensile bond strengths (TBS) were tested. XPS analysis of group SS showed the presence of saliva and silicone (Si) contamination on the surface. The ratios of carbon/zirconium and oxygen/zirconium for groups PA and AA were comparable to those ratios obtained for group CL, indicating the removal of the organic saliva contamination. Airborne-particle abrasion and acetone completely removed Si contamination from ceramic surfaces. Isopropanol had little cleaning effect on the two contaminants. TBS (median +/- standard deviation) in MPa of the groups SS (11.6 +/- 3.1), AL (10.0 +/- 2.9), and AC (13.0 +/- 2.8) were statistically lower than those of groups PA (33.6 +/- 5.5), AA (40.1 +/- 3.6), and CL (47.0 +/- 8.1) (p < 0.001), while no differences were found in TBS between groups AA and CL (p > 0.5). Contamination significantly reduced bond strengths to zirconia ceramic. Airborne-particle abrasion was the most effective cleaning method.
authors.affiliation: Department of Prosthodontics, Christian-Albrechts University at Kiel, Arnold-Heller-Str. 16, 24105 Kiel, Germany. ybin@proth.uni-kiel.de
authors.forename: Bin
authors.initials: B
authors.lastname: Yang
authors.forename: Michael
authors.initials: M
authors.lastname: Scharnberg
authors.forename: Stefan
authors.initials: S
authors.lastname: Wolfart
authors.forename: Anne C
authors.initials: AC
authors.lastname: Quaas
authors.forename: Klaus
authors.initials: K
authors.lastname: Ludwig
authors.forename: Rainer
authors.initials: R
authors.lastname: Adelung
authors.forename: Matthias
authors.initials: M
authors.lastname: Kern
mesh_terms: D002516:Ceramics; D001840:Dental Bonding; D003764:Dental Materials; D003793:Dental Restoration, Permanent; D004340:Drug Contamination; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D012463:Saliva; D013057:Spectrum Analysis; D013499:Surface Properties; D013718:Tensile Strength; D014965:X-Rays; D015040:Zirconium
chemical_list: D003764:Dental Materials; D015040:Zirconium; C028541:zirconium oxide