title: Effect of fluoride varnish and gel on dental erosion in primary and permanent teeth.
abstract: OBJECTIVE
  To assess the effect of a fluoride varnish and gel on the erosive wear of primary and permanent teeth.
  
  
  METHODS
  Sixty human primary (n=30) and permanent (n=30) enamel specimens were randomly assigned to one of the following groups: APF gel (1.23% F), NaF varnish (2.26% F), and control (no treatment). Fluoride gel was applied for 4 min and fluoride varnish for 24 h. Six daily demineralisation-remineralization cycles of 5 min of immersion in a cola drink (pH 2.3) and 30 min in artificial saliva were conducted during 7 days. All specimens were stored in artificial saliva between and after cycles. Surface Knoop microhardness (%SMHC) readings were performed at baseline, 48 h and 7 days. Data were tested using ANOVA and Tukey's tests (p<0.05).
  
  
  RESULTS
  For primary enamel, the mean %SMHC (+/-SD) after 48 h and 7 days was, respectively: gel (31.0+/-14.4 and 36.9+/-7.5), varnish (26.7+/-9.5 and 38.3+/-8.7), and control (35.8+/-8.6 and 45.0+/-8.6). For permanent enamel, such values were: gel (37.5+/-7.7 and 27.8+/-7.5), varnish (31.7+/-9.6 and 27.4+/-11.1) and control (48.6+/-6.4 and 43.1+/-6.4). In primary enamel, erosion inhibition by fluoride was not significant at 48 h (p=0.203) and 7 days (p=0.082). In permanent specimens, both products showed a significant effect (p<0.001).
  
  
  CONCLUSIONS
  Both fluoride varnish and gel were able to inhibit erosive enamel loss but mainly in the permanent experimental groups. Primary and permanent enamel substrates reacted differently to both demineralization by a cola drink and remineralization by fluoridated compounds.
authors.affiliation: Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of São Paulo, Av. Lineu Prestes, 2227, 05508-000 São Paulo, SP, Brazil. chrismurakami@gmail.com
authors.forename: Christiana
authors.initials: C
authors.lastname: Murakami
authors.forename: Marcelo
authors.initials: M
authors.lastname: Bönecker
authors.forename: Maria Salete Nahás Pires
authors.initials: MS
authors.lastname: Corrêa
authors.forename: Fausto Medeiros
authors.initials: FM
authors.lastname: Mendes
authors.forename: Célia Regina Martins Delgado
authors.initials: CR
authors.lastname: Rodrigues
mesh_terms: D000149:Acidulated Phosphate Fluoride / Q000008:administration & dosage*; D000367:Age Factors; D002253:Carbonated Beverages / Q000009:adverse effects; D003743:Dental Enamel / Q000254:growth & development; D003747:Dental Enamel Solubility; D019229:Dentition, Permanent; D005460:Fluorides, Topical / Q000008:administration & dosage*; D005782:Gels; D006244:Hardness; D006801:Humans; D010150:Paint; D012969:Sodium Fluoride / Q000008:administration & dosage*; D017001:Tooth Demineralization; D014077:Tooth Erosion / Q000139:chemically induced / Q000517:prevention & control*; D014094:Tooth, Deciduous / Q000503:physiopathology*
chemical_list: D005460:Fluorides, Topical; D005782:Gels; D000149:Acidulated Phosphate Fluoride; D012969:Sodium Fluoride