title: Micromechanical versus chemical bonding between CoCr alloys and methacrylate resins.
abstract: BACKGROUND
  As adhesive systems for bonding to metals have developed in dentistry, considerable importance is attached to the preparation of the metal alloy for both mechanical and chemical bonding. Different grit sizes when sandblasting Cobalt Chromium (CoCr) will provide a different three-dimensional surface for bonding. Previous reports have shown that 4-Methacryloyloxyethyl trimellitic anhydride (4-Meta) resins offer high bond strengths to CoCr alloy, with various surface preparations providing varying bond strengths. The relevance of this to bond strength was assessed.
  
  
  OBJECTIVE
  The aim of the study was to evaluate the importance of grit size of alumina in the preparation of CoCr alloy and to determine the effect on the tensile bond strength of four different acrylic resins to the CoCr alloy.
  
  
  METHODS
  Ten specimens were prepared within each group of four resins. Four grit sizes were assessed, 50, 110, 250 microm, and a range from 180 to 330 microm. The specimens were tested both within one day of production after storing at 37 degrees C in phosphate-buffered saline for seven days and after thermocycling.
  
  
  RESULTS
  Grit size resulted in a change in average contact surface area available for bonding. A significant difference (p < 0.01) existed in bond strengths between each of the materials, but no significant difference (p = 0.0673) was determined when different grit sizes were included.
  
  
  CONCLUSIONS
  It was concluded that grit size determined the available contact surface area of CoCr alloy for bonding but did not determine the bond strength that could be achieved between acrylic resins and CoCr alloy as a result of the poor adaptation of the resin to the complex surface topography.
authors.affiliation: University Dental Hospital Manchester, Higher Cambridge Street, Manchester M15 6FH, United Kingdom. craig.barclay@manchester.ac.uk
authors.forename: Craig W
authors.initials: CW
authors.lastname: Barclay
authors.forename: Donald
authors.initials: D
authors.lastname: Spence
authors.forename: William R E
authors.initials: WR
authors.lastname: Laird
authors.forename: Peter M
authors.initials: PM
authors.lastname: Marquis
authors.forename: Liam
authors.initials: L
authors.lastname: Blunt
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D001696:Biomechanical Phenomena; D002858:Chromium Alloys / Q000737:chemistry*; D003738:Dental Cements / Q000737:chemistry*; D003829:Denture, Partial; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D000180:Acrylic Resins; D002858:Chromium Alloys; D003738:Dental Cements; D008689:Methacrylates