title: Pilot study of the relationship between the hardness and abrasion resistance of two base metal alloys used for metal-ceramic restorations.
abstract: BACKGROUND
  Base metal alloys present high values of strength and hardness, which have been associated with the greater abrasion resistance and polishing of metal-ceramic restorations. However, surface hardness has been shown to be a poor indicator of abrasion resistance.
  
  
  OBJECTIVE
  The study aimed to compare the hardness and abrasion resistance of Ni-Cr alloys and determine whether there is a correlation between these 2 properties.
  
  
  METHODS
  Two Ni-Cr alloys for metal-ceramic restorations with different hardness values were subjected to the following procedures: (1) initial measurement of Vickers hardness, (2) a series of abrasion cycles, (3) measurement of mass loss after each cycle, and (4) Vickers hardness measurements after each cycle.
  
  
  RESULTS
  For each alloy, linear regression revealed a negative correlation between hardness and reduction in mass. The higher hardness of alloy A was associated with higher mass loss during abrasion when compared with alloy B.
  
  
  CONCLUSIONS
  There was no significant correlation between hardness and mass loss for either alloy.
authors.affiliation: Department of Dental Materials and Protheses, School of Dentistry of Ribeirão Preto, University of São Paulo, São Paulo, Brazil. olbezzon@forp.usp.br
authors.forename: O L
authors.initials: OL
authors.lastname: Bezzon
authors.forename: C
authors.initials: C
authors.lastname: de Barros
authors.forename: J M
authors.initials: JM
authors.lastname: de Almeida Rollo
authors.forename: P L
authors.initials: PL
authors.lastname: Di Lorenzo
mesh_terms: D002858:Chromium Alloys / Q000737:chemistry*; D003722:Dental Alloys / Q000737:chemistry*; D003775:Dental Polishing; D006244:Hardness; D006801:Humans; D016014:Linear Models; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000737:chemistry*; D010865:Pilot Projects; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical; D013499:Surface Properties
chemical_list: D002858:Chromium Alloys; D003722:Dental Alloys; D016876:Metal Ceramic Alloys