title: In vivo effects of a SnF2 gel on acid-softened enamel.
abstract: The purpose of this investigation was to study the intra-oral rehardening of acid-softened enamel and fluoride uptake from SnF2 gel. Bovine enamel slabs were softened with 0.1 mol/L lactate buffer at pH 4.0 for 14 hrs and then mounted in a mandibular removable Hawley appliance. Control slabs were worn for 96 hrs by seven adult males whose teeth were brushed daily with a fluoride-free dentifrice. Test slabs were exposed once/day to 0.4% SnF2 gel. The gel was swabbed onto the slabs for one minute before being replaced in the mouth unrinsed. The natural dentition was brushed 4 X /day with a fluoride-free dentifrice. Microhardness testing was performed after intra-oral exposure (IOE) and after acid-resistance-testing (ART) following immersion in 0.01 mol/L lactate buffer for 24 hrs at pH of 4.0. Fluoride uptake was measured on separate controls, test slabs, and test slabs after ART, with 0.5 mol/L HClO4 etches of from 15 to 60 sec. The F content was measured with a F-ion-specific electrode and the phosphate content by spectrophotometry. Following IOE, microhardness recovery was 35.6% for control and 37.9% for test slabs, and control slabs retained 1.4% resistance to acid, as compared with 18.6% for the test slabs. The F content of control slabs was significantly less than that of SnF2-treated slabs from 5 to 60 micron in depth, and the F content of SnF2-treated slabs after ART was significantly less at depths of from 5 to 35 micron than that of SnF2-treated slabs not exposed to ART. Both control and SnF2 enamel slabs demonstrated rehardening after IOE, but only SnF2-treated enamel retained a significant fraction of that rehardening after ART.
authors.forename: J W
authors.initials: JW
authors.lastname: Clark
authors.forename: A
authors.initials: A
authors.lastname: Quiros
authors.forename: R E
authors.initials: RE
authors.lastname: Corpron
authors.forename: F G
authors.initials: FG
authors.lastname: More
authors.forename: C J
authors.initials: CJ
authors.lastname: Kowalski
mesh_terms: D000328:Adult; D000818:Animals; D002417:Cattle; D003731:Dental Caries / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D003743:Dental Enamel / Q000032:analysis / Q000187:drug effects* / Q000473:pathology; D003747:Dental Enamel Solubility / Q000187:drug effects; D005459:Fluorides / Q000032:analysis / Q000494:pharmacology*; D005460:Fluorides, Topical; D006244:Hardness; D006801:Humans; D008297:Male; D008875:Middle Aged; D014002:Tin Fluorides / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D005460:Fluorides, Topical; D014002:Tin Fluorides; D005459:Fluorides