title: Ferric sulphate alterations on primary dentin and the adhesive interface.
abstract: OBJECTIVE
  The purpose of this study was to test the hypothesis that the pulp medication ferric sulphate (FS) may remain on primary dentin, affecting its microchemical structure and the bond strength of adhesives to primary dentin.
  
  
  METHODS
  The effects of FS and pre-bonding conditioning (37% phosphoric acid [PA] for 15 s or a self-etching primer, with or without the use of 2% chlorhexidine [CHX]) on FS-treated primary dentin were characterized using optical microscopy with Masson's and Perls' stains, variable-pressure SEM/energy-dispersive x-ray spectroscopy (VP-SEM/EDS), Fourier transform infrared spectroscopy (FT-IR), and x-ray diffraction. Ferric sulphate was applied for 30 s or 1 h for microchemical analysis. The adhesive interface and the bond strength were studied by VP-SEM/EDS and the μTBS test (1 mm2 bars, crosshead speed 0.5 mm/min), respectively. The study groups were: etch-and-rinse (E&R, Excite) adhesive (group 1); FS+E&R (group 2); FS+CHX+E&R (group 3); self-etching (SE, Adper Scotchbond) adhesive (group 4); FS+SE (group 5); FS+CHX+SE (group 6).
  
  
  RESULTS
  Ferric sulphate application produced demineralization, gypsum formation, and adsorption of Fe on the dentin surface, and it modified the collagen structure of primary dentin. There were no effects of FS on bond strength of the tested etch-and-rinse adhesive system. FS slightly reduced the bond strength between the primary dentin and the SE adhesive, and the values were not restored by CHX (group 4 = 17.58 ± 5.52 MPa > group 5 = 14.26 ± 7.08 MPa = group 6 = 13.96 ± 4.87 MPa).
  
  
  CONCLUSIONS
  Ferric sulphate alters the microchemical structure of primary dentin and can impair the adhesive strength of some self-etching adhesives.
authors.forename: M Esther
authors.initials: ME
authors.lastname: Rodríguez-Priego
authors.forename: M Victoria
authors.initials: MV
authors.lastname: Bolaños-Carmona
authors.forename: Santiago
authors.initials: S
authors.lastname: González-López
authors.forename: Alejandro
authors.initials: A
authors.lastname: Rodríguez-Navarro
authors.forename: M Purificación
authors.initials: MP
authors.lastname: Sánchez-Sánchez
mesh_terms: D000134:Acid Etching, Dental; D000327:Adsorption; D002133:Calcium Sulfate / Q000737:chemistry; D002648:Child; D002710:Chlorhexidine / Q000737:chemistry; D003094:Collagen / Q000187:drug effects; D001840:Dental Bonding; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000187:drug effects* / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry / Q000494:pharmacology*; D006397:Hematinics / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D010756:Phosphoric Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013997:Time Factors; D017001:Tooth Demineralization / Q000139:chemically induced; D014094:Tooth, Deciduous / Q000187:drug effects* / Q000648:ultrastructure; D014961:X-Ray Diffraction
chemical_list: D017220:Dentin-Bonding Agents; C420130:Excite cement; D005290:Ferric Compounds; D006397:Hematinics; D008689:Methacrylates; D010756:Phosphoric Acids; D019279:Resin Cements; C024823:ferric sulfate; D003094:Collagen; C041330:Scotchbond; C030242:phosphoric acid; D002710:Chlorhexidine; D002133:Calcium Sulfate