title: Effect of different surface treatments on the hydrothermal degradation of a 3Y-TZP ceramic for dental implants.
abstract: OBJECTIVE
  Implant surface modifications are intended to enhance bone integration. The objective of this study was to assess the effect of different surface treatments on the resistance to hydrothermal degradation, hardness and elastic modulus of a 3Y-TZP ceramic used for dental implants.
  
  
  METHODS
  Samples grouped according to their surface morphologies (AS, as-sintered; C, coated; P, dry-polished; R, roughened; PA, polished and annealed; RA, roughened and annealed) were subjected to accelerated hydrothermal degradation (LTD) by exposure to water steam (134°C, 2bars) for 100h. The t-m phase transformation was quantified by grazing incidence X-ray diffraction (GIXDR) and by combined focused ion beam and scanning electron microscopy (FIB-SEM). Elastic modulus and hardness before- and after prolonged aging (100h) were assessed by nanoindentation.
  
  
  RESULTS
  AS and C specimens presented a better resistance to hydrothermal degradation than P and R samples. After prolonged aging, the depth of the monoclinic transformed layer ranged from 11μm to 14μm. Hydrothermal degradation led to a significant decrease of elastic modulus and hardness.
  
  
  CONCLUSIONS
  Surface treatments affected the resistance to hydrothermal degradation of the 3Y-TZP ceramic. Dry mechanical surface modifications should be avoided since a high t-m transformation rate associated to the initial monoclinic content was observed. Annealing was useful to reverse the initial t-m transformation, but did not improve the resistance to hydrothermal degradation.
authors.affiliation: Division of Fixed Prosthodontics and Biomaterials, School of Dentistry, University of Geneva, Geneva, Switzerland. Electronic address: Maria.Cattani-Lorente@unige.ch.
authors.forename: M
authors.initials: M
authors.lastname: Cattani-Lorente
authors.affiliation: Division of Fixed Prosthodontics and Biomaterials, School of Dentistry, University of Geneva, Geneva, Switzerland.
authors.forename: S S
authors.initials: SS
authors.lastname: Scherrer
authors.affiliation: Division of Fixed Prosthodontics and Biomaterials, School of Dentistry, University of Geneva, Geneva, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Durual
authors.affiliation: UMR CNRS 5510 (MATEIS), INSA-Lyon, Villeurbanne, France; Department of Biomaterials, Faculty of Odontology, University Lyon 1, Lyon, France.
authors.forename: C
authors.initials: C
authors.lastname: Sanon
authors.affiliation: UMR CNRS 5510 (MATEIS), INSA-Lyon, Villeurbanne, France.
authors.forename: T
authors.initials: T
authors.lastname: Douillard
authors.affiliation: UMR CNRS 5510 (MATEIS), INSA-Lyon, Villeurbanne, France.
authors.forename: L
authors.initials: L
authors.lastname: Gremillard
authors.affiliation: UMR CNRS 5510 (MATEIS), INSA-Lyon, Villeurbanne, France.
authors.forename: J
authors.initials: J
authors.lastname: Chevalier
authors.affiliation: Division of Fixed Prosthodontics and Biomaterials, School of Dentistry, University of Geneva, Geneva, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Wiskott
mesh_terms: D002516:Ceramics; D015921:Dental Implants; D006358:Hot Temperature; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D015921:Dental Implants
keywords: 3Y-TZP ceramic; Elastic modulus; FIB-SEM; GIXRD; LTD; Nanoindentation; Surface hardness