title: Stannous fluoride/sodium hexametaphosphate dentifrice increases dentin resistance to tubule exposure in vitro.
abstract: OBJECTIVE
  The purpose of this study was to compare the reactivity of three dentifrice formulations on smear layer-covered root dentin surfaces, and the effects of the formulation treatments on resistance to acid softening and dentinal tubuli disclosure.
  
  
  METHODS
  Commercial dentifrices, including Crest Cavity Protection Regular, Colgate Total, and a new dentifrice comprised of stannous fluoride/sodium hexametaphosphate (SnF2/HMP: Crest Pro-Health), were cycled through a pre-treatment period on smear layer-covered dentin surfaces, including intermittent soaking in dentifrice slurries and whole human saliva immersion. Following pre-treatments, the cycling treatments were modified to include dietary acid exposure, including soaks in an acidic soft drink. Vickers surface microhardness, variable pressure scanning electron microscopy (VP-SEM), and confocal laser scanning microscopy in reflection mode (CLSM) were used to characterize dentin reactivity and smear layer protection.
  
  
  RESULTS
  CLSM and SEM analyses showed that specimens treated with SnF2/HMP appeared to resist acid solubilization, evidenced by the absence of disclosed dentinal tubuli. The histo-tomographic observations in this study were in agreement with the hardness measurements. The superior surface protection of dentin with SnF2/HMP would suggest potential benefits in ameliorating dentinal hypersensitivity in the clinical situation.
  
  
  CONCLUSIONS
  A stannous fluoride/sodium hexametaphosphate dentifrice prevents dietary acid softening and tubule exposure of smear layer dentin surfaces.
authors.affiliation: Procter & Gamble Health Care Research Center, Mason, Ohio, USA. White.dj.1@pg.com
authors.forename: Donald J
authors.initials: DJ
authors.lastname: White
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Lawless
authors.forename: Ayowumi
authors.initials: A
authors.lastname: Fatade
authors.forename: Arif
authors.initials: A
authors.lastname: Baig
authors.forename: Roxana
authors.initials: R
authors.lastname: von Koppenfels
authors.forename: Heinz
authors.initials: H
authors.lastname: Duschner
authors.forename: Hermann
authors.initials: H
authors.lastname: Götz
mesh_terms: D003802:Dentifrices / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D003807:Dentin Sensitivity / Q000517:prevention & control*; D003808:Dentin Solubility / Q000187:drug effects*; D004338:Drug Combinations; D006244:Hardness; D006801:Humans; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D010710:Phosphates / Q000494:pharmacology / Q000627:therapeutic use*; D016369:Smear Layer; D014002:Tin Fluorides / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D003802:Dentifrices; D004338:Drug Combinations; D010710:Phosphates; D014002:Tin Fluorides; C009285:sodium polymetaphosphate