title: A new testing protocol for zirconia dental implants.
abstract: OBJECTIVE
  Based on the current lack of standards concerning zirconia dental implants, we aim at developing a protocol to validate their functionality and safety prior their clinical use. The protocol is designed to account for the specific brittle nature of ceramics and the specific behavior of zirconia in terms of phase transformation.
  
  
  METHODS
  Several types of zirconia dental implants with different surface textures (porous, alveolar, rough) were assessed. The implants were first characterized in their as-received state by Scanning Electron Microscopy (SEM), Focused Ion Beam (FIB), X-Ray Diffraction (XRD). Fracture tests following a method adapted from ISO 14801 were conducted to evaluate their initial mechanical properties. Accelerated aging was performed on the implants, and XRD monoclinic content measured directly at their surface instead of using polished samples as in ISO 13356. The implants were then characterized again after aging.
  
  
  RESULTS
  Implants with an alveolar surface presented large defects. The protocol shows that such defects compromise the long-term mechanical properties. Implants with a porous surface exhibited sufficient strength but a significant sensitivity to aging. Even if associated to micro cracking clearly observed by FIB, aging did not decrease mechanical strength of the implants.
  
  
  CONCLUSIONS
  As each dental implant company has its own process, all zirconia implants may behave differently, even if the starting powder is the same. Especially, surface modifications have a large influence on strength and aging resistance, which is not taken into account by the current standards. Protocols adapted from this work could be useful.
authors.affiliation: INSA-Lyon, UMR CNRS 5510 (MATEIS), 7 avenue Jean Capelle, 69621 Villeurbanne Cedex, France; University Lyon 1, Faculty of Odontology, Department of Biomaterials, 11, Rue Guillaume Paradin, 69372 Lyon Cedex 08, France.
authors.forename: Clarisse
authors.initials: C
authors.lastname: Sanon
authors.affiliation: INSA-Lyon, UMR CNRS 5510 (MATEIS), 7 avenue Jean Capelle, 69621 Villeurbanne Cedex, France; Institut Universitaire de France, 103 bd Saint-Michel, Paris 75005, France. Electronic address: jerome.chevalier@insa-lyon.fr.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Chevalier
authors.affiliation: INSA-Lyon, UMR CNRS 5510 (MATEIS), 7 avenue Jean Capelle, 69621 Villeurbanne Cedex, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Douillard
authors.affiliation: University of Geneva, School of Dental Medicine, Department of Prosthodontics-Biomaterials, 19 rue Barthélémy-Menn, CH 1205 Geneva, Switzerland.
authors.forename: Maria
authors.initials: M
authors.lastname: Cattani-Lorente
authors.affiliation: University of Geneva, School of Dental Medicine, Department of Prosthodontics-Biomaterials, 19 rue Barthélémy-Menn, CH 1205 Geneva, Switzerland.
authors.forename: Susanne S
authors.initials: SS
authors.lastname: Scherrer
authors.affiliation: INSA-Lyon, UMR CNRS 5510 (MATEIS), 7 avenue Jean Capelle, 69621 Villeurbanne Cedex, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Gremillard
mesh_terms: D015921:Dental Implants; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D013499:Surface Properties; D014961:X-Ray Diffraction; D015040:Zirconium / Q000737:chemistry*
chemical_list: D015921:Dental Implants; D015040:Zirconium; C028541:zirconium oxide
keywords: Aging; Fracture; Implants; Phase transformation; Surface; Zirconia