title: Tensile strength of Ni-Cr copings subjected to inner surface sandblasting using different cementing agents: An in vitro study.
abstract: OBJECTIVE
  To evaluate the effect of thermal cycling and inner surface treatment with aluminum oxide at different granulations on the tensile strength of Ni-Cr copings cemented with different cementing agents.
  
  
  METHODS
  Ninety-six metal copings were manufactured and divided into two groups: before and after thermal cycling (n = 48). The copings of both groups were internally treated by sandblasting with aluminum oxide particles of 100 (n = 24) and 320 (n = 24) mesh. The copings were cemented on previously manufactured metal cores using zinc phosphate (n = 8), conventional glass ionomer (CGIC) (n = 8) and resin-modified glass ionomer (RMGIC) (n = 8) cements. The tensile strength before and after thermal cycling was then determined (Newtons).
  
  
  RESULTS
  The tensile strength before and after thermal cycling was significantly higher in copings cemented with RMGIC compared to CGIC (p < 0.05) and was similar to that for zinc phosphate (p > 0.05). Thermal cycling and sandblasting of the inner surface of the metal copings with different granulations did not influence retention (p > 0.05).
  
  
  CONCLUSIONS
  Zinc phosphate cements and RMGIC showed similar retention. Additionally, the retention of the cements was not influenced by either thermal cycling or the particle size of the aluminum oxide.
authors.affiliation: a University of São Paulo, Ribeirão Preto School of Dentistry, Department of Dental Materials and Prosthodontics , Ribeirão Preto, São Paulo, Brazil.
authors.forename: Raniel Fernandes
authors.initials: RF
authors.lastname: Peixoto
authors.affiliation: a University of São Paulo, Ribeirão Preto School of Dentistry, Department of Dental Materials and Prosthodontics , Ribeirão Preto, São Paulo, Brazil.
authors.forename: Marília Pedrão
authors.initials: MP
authors.lastname: Hermanson
authors.affiliation: a University of São Paulo, Ribeirão Preto School of Dentistry, Department of Dental Materials and Prosthodontics , Ribeirão Preto, São Paulo, Brazil.
authors.forename: Denise
authors.initials: D
authors.lastname: Pupim
authors.affiliation: a University of São Paulo, Ribeirão Preto School of Dentistry, Department of Dental Materials and Prosthodontics , Ribeirão Preto, São Paulo, Brazil.
authors.forename: Renata Cristina Silveira
authors.initials: RC
authors.lastname: Rodrigues
authors.affiliation: a University of São Paulo, Ribeirão Preto School of Dentistry, Department of Dental Materials and Prosthodontics , Ribeirão Preto, São Paulo, Brazil.
authors.forename: Rossana Pereira Almeida
authors.initials: RP
authors.lastname: Antunes
authors.affiliation: a University of São Paulo, Ribeirão Preto School of Dentistry, Department of Dental Materials and Prosthodontics , Ribeirão Preto, São Paulo, Brazil.
authors.forename: Maria da Gloria Chiarello
authors.initials: Mda G
authors.lastname: de Mattos
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D002484:Cementation / Q000379:methods; D002858:Chromium Alloys / Q000737:chemistry*; D003442:Crowns; D003735:Dental Casting Technique; D003738:Dental Cements / Q000737:chemistry*; D045662:Dental Etching / Q000379:methods*; D017268:Dental Prosthesis Retention; D003799:Dental Stress Analysis; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013718:Tensile Strength; D015036:Zinc Phosphate Cement / Q000737:chemistry
chemical_list: D002858:Chromium Alloys; D003738:Dental Cements; D005899:Glass Ionomer Cements; D019279:Resin Cements; D015036:Zinc Phosphate Cement; D000537:Aluminum Oxide
keywords: Tensile strength; dental cements; metal coping; thermal cycling