title: Comparison between the effect of plasma and chemical treatments on fiber post surface.
abstract: BACKGROUND
  The aim of the present study was to evaluate the fiber post surface after plasma and usual treatments and the adhesion between treated fiber posts and Rely X Unicem resin cement (3M ESPE, St Paul, MN).
  
  
  METHODS
  Flat fiber posts were divided into 6 groups according to surface treatment: silane, hydrofluoric acid, hydrofluoric acid plus silane, plasma polymerization with argon, ethylenediamine plasma (EDA), and the control group. A goniometer was used to measure the contact angle between the groups with water or resin cement. Scanning electron microscopy and electron dispersive spectroscopy were used to examine the topography and chemical changes in the post surfaces after treatment. Push-out tests were performed using a universal testing machine to evaluate the adhesion strength between treated fiber posts and resin cement.
  
  
  RESULTS
  In the contact angle with water, the most hydrophilic surface was observed in samples treated with argon plasma, followed by treatments with silane and hydrofluoric acid plus silane. The hydrophobic characteristic was observed with EDA and hydrofluoric acid. The contact angle with dual resin cement showed lower values with argon and EDA, followed by silane and hydrofluoric acid plus silane. Electron dispersive spectroscopy analyses showed chemical modifications in the surface after different treatments although topographic changes were verified only with EDA plasma compared with the control. Push-out results did not show differences between groups compared with the control, except for EDA plasma treatment.
  
  
  CONCLUSIONS
  Plasma treatment favored the wettability of the post surface by modifying it chemically. Adhesion improvement was only observed after EDA treatment.
authors.affiliation: Department of Metallurgic and Materials Engineering, Federal University of Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Marta Cléa
authors.initials: MC
authors.lastname: Costa Dantas
authors.forename: Maíra
authors.initials: M
authors.lastname: do Prado
authors.forename: Vinicius Silva
authors.initials: VS
authors.lastname: Costa
authors.forename: Mauro G
authors.initials: MG
authors.lastname: Gaiotte
authors.forename: Renata A
authors.initials: RA
authors.lastname: Simão
authors.forename: Fernando Luis
authors.initials: FL
authors.lastname: Bastian
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D001128:Argon / Q000737:chemistry; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D004853:Epoxy Resins / Q000737:chemistry; D005029:Ethylenediamines / Q000737:chemistry; D006801:Humans; D006858:Hydrofluoric Acid / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D058626:Plasma Gases / Q000737:chemistry*; D058105:Polymerization; D011176:Post and Core Technique / Q000295:instrumentation*; D019279:Resin Cements / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry; D046590:Spectroscopy, Electron Energy-Loss; D013314:Stress, Mechanical; D013499:Surface Properties; D014867:Water / Q000737:chemistry; D017155:Wettability
chemical_list: C542237:3-methacryloxypropyltrimethoxysilane; D003764:Dental Materials; D004853:Epoxy Resins; D005029:Ethylenediamines; D008689:Methacrylates; D058626:Plasma Gases; C483701:Rely X Unicem; D019279:Resin Cements; D012821:Silanes; D014867:Water; C031234:ethylenediamine; D001128:Argon; D006858:Hydrofluoric Acid