title: Tomography of indentation cracks in feldspathic dental porcelain on zirconia.
abstract: OBJECTIVE
  The objective of this work is to study the crack produced by spherical and sharp indentation on veneering feldspathic dental porcelain in order to understand the morphology of the cracks in the surface and beneath the indentation using a tomographic technique. The geometry of cracks produced under contact loading are directly related to the structural integrity and reliability of dental prosthesis.
  
  
  METHODS
  Monotonic Hertzian contact loading and nanoindentation tests were performed on feldspathic porcelain (VITA-VM9) coatings. Residual imprints and the cracks produced by the indentations were characterized by 3-dimensional reconstruction using focused ion beam tomography.
  
  
  RESULTS
  Under nanoindentation, the propagating crack deflects due to the interaction with the leucite particles resulting in a crack with a complex morphology. Under spherical contact loading, multiple ring cracks were observed at the surface, with a conical shape beneath the residual imprint.
  
  
  CONCLUSIONS
  These results will help to improve the mechanical performance of these materials by detecting potential causes of failure for the long term structural integrity and reliability of the prosthesis.
authors: Department of Materials Science and Metallurgy, Universitat Politècnica de Catalunya, Barcelona, Spain. astrid.rueda@upc.edu
authors: Astrid O
authors: AO
authors: Rueda
authors: Jordi
authors: J
authors: Seuba
authors: Marc
authors: M
authors: Anglada
authors: Emilio
authors: E
authors: Jiménez-Piqué
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry*; D003799:Dental Stress Analysis; D055119:Elastic Modulus; D006244:Hardness; D013499:Surface Properties; D014054:Tomography; D015040:Zirconium / Q000737:chemistry*
chemical_list: D000538:Aluminum Silicates; D003776:Dental Porcelain; C078519:leucite; D015040:Zirconium; C028541:zirconium oxide