title: Protective effects of SnF2 - Part II. Deposition and retention on pellicle-coated enamel.
abstract: Deposition of an acid-resistant barrier onto enamel represents a potentially superior means for delivering protection against dietary, erosive acid challenges.
  
  
  OBJECTIVE
  The purpose of this study was to demonstrate the ability of a stabilised stannous fluoride (SnF2 ) dentifrice to: (1) deposit a SnF2 barrier layer onto pellicle-coated enamel surfaces; (2) increase the intensity of the barrier layer over time; and (3) be retained on the enamel surface for hours after product use.
  
  
  METHODS
  Squares of human enamel were exposed to pooled saliva for 1 hour (pellicle formation) and separated into six sets. Set 1 was treated with the supernatant of a 1:3 slurry of the test dentifrice (Crest(®) Pro-Health(®) : water for 2 minutes), then rinsed. Set 2 was treated in the same manner and then placed into saliva (6 hours). Set 3 was cycled through seven repeated treatments. Set 4 was treated for seven cycles and then placed into saliva (6 hours). Set 5 was a water control, and set 6 was a water control that remained in saliva for 6 hours. Surface analysis of specimens was done using laser ablation Inductively Coupled Plasma Mass Spectroscopy (ICP-MS).
  
  
  RESULTS
  Deposition of a barrier layer was demonstrated, beginning with the initial treatment, with Sn (using isotopes (117) Sn + (120) Sn) measured on the enamel surface as the reference marker. Deposition of the barrier layer was greater after seven cycles, and the retention of this layer was highly significant (P = 0.05, anova: 6 hours).
  
  
  CONCLUSIONS
  This study confirms that: (1) the stabilised SnF2 dentifrice deposits a barrier layer onto the enamel surface, beginning with the first use of the product; (2) this barrier is enhanced following multiple treatments; and (3) the barrier layer is retained on the enamel surface for hours after product use.
authors.affiliation: The Procter & Gamble Company, Mason, OH, USA.
authors.forename: Deepa
authors.initials: D
authors.lastname: Khambe
authors.forename: Sandra L
authors.initials: SL
authors.lastname: Eversole
authors.forename: Timothy
authors.initials: T
authors.lastname: Mills
authors.forename: Robert V
authors.initials: RV
authors.lastname: Faller
mesh_terms: D003743:Dental Enamel / Q000737:chemistry / Q000378:metabolism*; D044622:Dental Pellicle / Q000737:chemistry / Q000378:metabolism*; D003802:Dentifrices / Q000032:analysis / Q000493:pharmacokinetics; D006801:Humans; D007554:Isotopes; D053844:Lasers, Solid-State; D010710:Phosphates / Q000032:analysis / Q000493:pharmacokinetics; D020011:Protective Agents / Q000032:analysis / Q000493:pharmacokinetics; D013054:Spectrophotometry, Atomic / Q000295:instrumentation / Q000379:methods; D013997:Time Factors; D014002:Tin Fluorides / Q000032:analysis / Q000493:pharmacokinetics*; D014004:Tin Radioisotopes; D014867:Water / Q000737:chemistry
chemical_list: C510825:Crest Pro-Health Dentifrice; D003802:Dentifrices; D007554:Isotopes; D010710:Phosphates; D020011:Protective Agents; D014002:Tin Fluorides; D014004:Tin Radioisotopes; D014867:Water
keywords: Erosion; fluoride; laser ablation; stannous fluoride; toothpaste