title: ADM guidance-Ceramics: Fracture toughness testing and method selection.
abstract: The objective is within the scope of the Academy of Dental Materials Guidance Project, which is to provide dental materials researchers with a critical analysis of fracture toughness (FT) tests such that the assessment of the FT of dental ceramics is conducted in a reliable, repeatable and reproducible way.
  
  
  
  Fracture mechanics theory and FT methodologies were critically reviewed to introduce basic fracture principles and determine the main advantages and disadvantages of existing FT methods from the standpoint of the dental researcher.
  
  
  
  The recommended methods for FT determination of dental ceramics were the Single Edge "V" Notch Beam (SEVNB), Single Edge Precracked Beam (SEPB), Chevron Notch Beam (CNB), and Surface Crack in Flexure (SCF). SEVNB's main advantage is the ease of producing the notch via a cutting disk, SEPB allows for production of an atomically sharp crack generated by a specific precracking device, CNB is technically difficult, but based on solid fracture mechanics solutions, and SCF involves fracture from a clinically sized precrack. The IF test should be avoided due to heavy criticism that has arisen in the engineering field regarding the empirical nature of the calculations used for FT determination.
  
  
  
  Dental researchers interested in FT measurement of dental ceramics should start with a broad review of fracture mechanics theory to understand the underlying principles involved in fast fracture of ceramics. The choice of FT methodology should be based on the pros and cons of each test, as described in this literature review.
authors.affiliation: Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, São Paulo, Brazil. Electronic address: paulofc@usp.br.
authors.forename: Paulo Francisco
authors.initials: PF
authors.lastname: Cesar
authors.affiliation: Post-Graduate Program in Dentistry, Dental School, University of Passo Fundo, Passo Fundo, Brazil. Electronic address: dbona@upf.br.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Della Bona
authors.affiliation: Division of Fixed Prosthodontics and Biomaterials, University Clinic of Dental Medicine, University of Geneva, Geneva, Switzerland. Electronic address: Susanne.Scherrer@unige.ch.
authors.forename: Susanne S
authors.initials: SS
authors.lastname: Scherrer
authors.affiliation: Research and Development Department VITA Zahnfabrik, Bad Saeckingen, Germany. Electronic address: M.Tholey@vita-zahnfabrik.com.
authors.forename: Michael
authors.initials: M
authors.lastname: Tholey
authors.affiliation: School of Clinical Dentistry, University of Sheffield, Sheffield, UK. Electronic address: r.vannoort@sheffield.ac.uk.
authors.forename: Richard
authors.initials: R
authors.lastname: van Noort
authors.affiliation: Department of Medical Biotechnologies, University of Siena, Siena, Italy. Electronic address: alessandrovichi1@gmail.com.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Vichi
authors.affiliation: Department of Reconstructive Dentistry and Center for Biomaterials, University of Connecticut Health Center, Farmington, USA. Electronic address: kelly@uchc.edu.
authors.forename: Robert
authors.initials: R
authors.lastname: Kelly
authors.affiliation: Research Laboratory for Dental Biomaterials, Dental Clinic 1, University of Erlangen-Nuernberg, Erlangen, Germany. Electronic address: ulrich.lohbauer@fau.de.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Lohbauer
mesh_terms: D002516:Ceramics; D003764:Dental Materials; D003776:Dental Porcelain; D008422:Materials Testing; D013314:Stress, Mechanical
chemical_list: D003764:Dental Materials; D003776:Dental Porcelain
keywords: Dental ceramics; Fractography; Fracture toughness; Mechanical properties