title: Effect of different airborne-particle abrasion/bonding agent combinations on the bond strength of a resin cement to a base metal alloy.
abstract: BACKGROUND
  Investigation of surface treatments to improve the bond of resin cements to metals may contribute to the longevity of metal ceramic restorations.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the efficacy of surface treatments on the shear bond strength (SBS) of a resin cement to nickel-chromium (NiCr) alloy.
  
  
  METHODS
  Eighty cast NiCr alloy disks (9 × 3 mm) were divided into 8 groups (n=10), which received 1 of the following surface treatments: 1) 50 µm Al(2)O(3) particles + silane; 2) 120 µm Al(2)O(3) + silane; 3) 30 µm silica-modified Al(2)O(3) (Cojet Sand) + silane; 4) 120 µm Al(2)O(3) followed by 110 µm silica-modified Al(2)O(3) (Rocatec) + silane; 5) 50 µm Al(2)O(3) + metal primer; 6) 120 µm Al(2)O(3) + metal primer; 7) 30 µm silica-modified Al(2)O(3) (Cojet Sand) + metal primer; and 8) 120 µm Al(2)O(3) followed by 110 µm silica-modified Al(2)O(3) (Rocatec) + metal primer. The silane was RelyX Ceramic Primer and the metal primer Alloy Primer. RelyX ARC resin cement was bonded to NiCr alloy surfaces. Specimens were thermally cycled before shear mode testing. Data (MPa) were analyzed by 1-way ANOVA and the Tukey test (α=.05). Failure mode was determined with a stereomicroscope (×20).
  
  
  RESULTS
  The results revealed that surface treatment was significant (P<.001). There was no significant difference between 50 µm and 120 µm Al(2)O(3) particles, regardless of the bonding agent used (silane or metal primer). Cojet Sand provided lower SBS than Rocatec, both in the groups treated with silane (P<.001) and metal primer (P<.01). No significant difference was observed between silane and metal primer in the groups abraded with 50 µm and 120 µm Al(2)O(3) particles. Metal primer decreased the SBS of both Cojet Sand and Rocatec groups (P<.001). Rocatec + silane had the highest SBS and Cojet Sand + metal primer the lowest. All groups presented 100% adhesive failure.
  
  
  CONCLUSIONS
  Particle size influenced SBS only in the groups abraded with silica-modified Al(2)O(3). The bonding agent did not affect SBS in the groups abraded with Al(2)O(3). Alloy Primer was not chemically compatible with silica-modified Al(2)O(3). Both mechanical (particle size) and chemical (silica/silane interaction) factors contributed to the high SBS of Rocatec + silane.
authors.affiliation: Department of Dental Materials and Prosthodontics, Araraquara Dental School, UNESP - São Paulo State University, Araraquara, São Paulo, Brazil. renata@foar.unesp.br
authors.forename: Renata Garcia
authors.initials: RG
authors.lastname: Fonseca
authors.forename: Samira Branco
authors.initials: SB
authors.lastname: Martins
authors.forename: Filipe
authors.initials: F
authors.lastname: de Oliveira Abi-Rached
authors.forename: Carlos Alberto
authors.initials: CA
authors.lastname: Dos Santos Cruz
mesh_terms: D020906:Air Abrasion, Dental; D000537:Aluminum Oxide; D017438:Bisphenol A-Glycidyl Methacrylate; D002858:Chromium Alloys; D001840:Dental Bonding; D003738:Dental Cements; D003799:Dental Stress Analysis; D008422:Materials Testing; D008689:Methacrylates; D010316:Particle Size; D011092:Polyethylene Glycols; D011109:Polymethacrylic Acids; D019279:Resin Cements; D033081:Shear Strength; D012821:Silanes / Q000737:chemistry; D013499:Surface Properties; D013871:Thiones
chemical_list: C521707:Alloy Primer; D002858:Chromium Alloys; D003738:Dental Cements; D008689:Methacrylates; D011109:Polymethacrylic Acids; C462240:RelyX ARC; D019279:Resin Cements; C076811:Rocatec; D012821:Silanes; D013871:Thiones; C100646:Metal Primer; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D000537:Aluminum Oxide