title: In vivo effects of fluoride on enamel permeability.
abstract: This in vivo study evaluated the effects of topical fluoride application on enamel by repeated scanning electron microscopy analysis of replicas. Baseline fluid droplets were employed as qualitative indication of enamel permeability. CaF(2)-like globules were detected in vivo after fluoride application and were not found after professional brushing, ultrasound action, or chemical extraction. Absence of water permeability of enamel was demonstrated even after removal of CaF(2)-like globules. Droplets reappeared within 1 h in sodium fluoride-treated teeth, but they did not reappear even after 1 week following topical enamel treatment with acidulated phosphate fluoride. Teeth treated with an acidulate fluoride-free solution showed lack of CaF(2)-like globules and no droplets for at least 1 week as detected in acidulate phosphate fluoride-treated teeth. The caries-preventing action of fluoride may be due to its ability to decrease permeability and diffusion pathways. CaF(2)-like globules seem to be indirectly involved in enamel protection over time maintaining an impermeable barrier, and phosphoric acid seemed to play an unexpected fluoride-independent preventive role.
authors.affiliation: Endodontics Unit, Department of Oral Sciences, Alma Mater Studiorum-University of Bologna, via San Vitale 59, 40125 Bologna, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Chersoni
authors.forename: Angelica
authors.initials: A
authors.lastname: Bertacci
authors.forename: David H
authors.initials: DH
authors.lastname: Pashley
authors.forename: Franklin R
authors.initials: FR
authors.lastname: Tay
authors.forename: Lucio
authors.initials: L
authors.lastname: Montebugnoli
authors.forename: Carlo
authors.initials: C
authors.lastname: Prati
mesh_terms: D000149:Acidulated Phosphate Fluoride / Q000494:pharmacology; D000328:Adult; D002124:Calcium Fluoride / Q000032:analysis / Q000737:chemistry; D002327:Cariostatic Agents / Q000494:pharmacology*; D003743:Dental Enamel / Q000187:drug effects / Q000648:ultrastructure; D003745:Dental Enamel Permeability / Q000187:drug effects*; D003777:Dental Prophylaxis / Q000295:instrumentation; D004058:Diffusion; D005460:Fluorides, Topical / Q000494:pharmacology*; D006801:Humans; D006878:Hydroxides / Q000494:pharmacology; D007180:Incisor / Q000187:drug effects / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D010539:Permeability / Q000187:drug effects; D010756:Phosphoric Acids / Q000494:pharmacology; D017680:Potassium Compounds / Q000494:pharmacology; D016628:Replica Techniques; D012969:Sodium Fluoride / Q000494:pharmacology; D013997:Time Factors; D014465:Ultrasonics; D014867:Water / Q000378:metabolism
chemical_list: D002327:Cariostatic Agents; D005460:Fluorides, Topical; D006878:Hydroxides; D010756:Phosphoric Acids; D017680:Potassium Compounds; D014867:Water; D000149:Acidulated Phosphate Fluoride; D012969:Sodium Fluoride; C030242:phosphoric acid; D002124:Calcium Fluoride; C029943:potassium hydroxide