title: Fatigue of dental ceramics.
abstract: OBJECTIVE
  Clinical data on survival rates reveal that all-ceramic dental prostheses are susceptible to fracture from repetitive occlusal loading. The objective of this review is to examine the underlying mechanisms of fatigue in current and future dental ceramics.
  
  
  METHODS
  The nature of various fatigue modes is elucidated using fracture test data on ceramic layer specimens from the dental and biomechanics literature.
  
  
  CONCLUSIONS
  Failure modes can change over a lifetime, depending on restoration geometry, loading conditions and material properties. Modes that operate in single-cycle loading may be dominated by alternative modes in multi-cycle loading. While post-mortem examination of failed prostheses can determine the sources of certain fractures, the evolution of these fractures en route to failure remains poorly understood. Whereas it is commonly held that loss of load-bearing capacity of dental ceramics in repetitive loading is attributable to chemically assisted 'slow crack growth' in the presence of water, we demonstrate the existence of more deleterious fatigue mechanisms, mechanical rather than chemical in nature. Neglecting to account for mechanical fatigue can lead to gross overestimates in predicted survival rates.
  
  
  CONCLUSIONS
  Strategies for prolonging the clinical lifetimes of ceramic restorations are proposed based on a crack-containment philosophy.
authors.affiliation: Department of Biomaterials and Biomimetics, New York University College of Dentistry, New York, NY 10010, USA. Electronic address: yz21@nyu.edu.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Irena
authors.initials: I
authors.lastname: Sailer
authors.forename: Brian R
authors.initials: BR
authors.lastname: Lawn
mesh_terms: D001732:Bite Force; D002516:Ceramics / Q000737:chemistry*; D055598:Chemical Phenomena; D003764:Dental Materials / Q000737:chemistry*; D019232:Dental Restoration Failure; D006801:Humans; D008422:Materials Testing; D013314:Stress, Mechanical
chemical_list: D003764:Dental Materials
keywords: Crowns; Dental ceramics; Fatigue; Fixed-partial dentures; Fracture modes; Lifetime