title: Contact fatigue of veneer feldspathic porcelain on dental zirconia.
abstract: OBJECTIVE
  To understand the resistance to cyclic and static contact loading of feldspathic porcelain on dental zirconia (3Y-TZP), in order to understand the partial failure of porcelain (chipping or cracking).
  
  
  METHODS
  Hertzian contact techniques were used to evaluate the appearance of damage as a ring crack in terms of applied load and number of cycles in air and simulated saliva.
  
  
  RESULTS
  Static contact loading showed the presence of stress corrosion cracking in the porcelain; the environmental crack growth in air was determined from the results of time to damage under static load. There was also a contribution of fatigue effects due to the interactions of the crack with the microstructure. From the obtained results, a time to failure was estimated depending on the material counterpart. Cracking can occur on porcelain coatings if the contact counterpart is teeth or porcelain in a time interval of a few years, consistent with clinical studies.
  
  
  CONCLUSIONS
  Contact loading, particularly against teeth or other ceramic materials can be a significant cause of failure and chipping of feldspathic porcelain on zirconia, especially if the patient suffers from bruxism. Protection, by e.g. a guard, against repetitive contact against the porcelain can increase the lifetime of the veneer.
authors.affiliation: Department of Materials Science and Metallurgical Engineering, Universitat Politècnica de Catalunya - BarcelonaTech, Barcelona, Spain.
authors.forename: A O
authors.initials: AO
authors.lastname: Rueda
authors.affiliation: Department of Materials Science and Metallurgical Engineering, Universitat Politècnica de Catalunya - BarcelonaTech, Barcelona, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Anglada
authors.affiliation: Department of Materials Science and Metallurgical Engineering, Universitat Politècnica de Catalunya - BarcelonaTech, Barcelona, Spain; Center for Research in Nano-engineering, CRNE, Universitat Politècnica de Catalunya, Barcelona, Spain. Electronic address: emilio.jimenez@upc.edu.
authors.forename: E
authors.initials: E
authors.lastname: Jimenez-Pique
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D003343:Corrosion; D003776:Dental Porcelain / Q000737:chemistry*; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D003801:Dental Veneers; D006813:Humidity; D008422:Materials Testing; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D017680:Potassium Compounds / Q000737:chemistry*; D012464:Saliva, Artificial / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors; D015019:Yttrium / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry*
chemical_list: D000538:Aluminum Silicates; D017680:Potassium Compounds; D012464:Saliva, Artificial; D003776:Dental Porcelain; C016447:feldspar; D015019:Yttrium; D015040:Zirconium; C028541:zirconium oxide
keywords: Fatigue; Feldspathic dental porcelain; Fracture; Hertzian contact; Zirconia