title: Distribution of fluoride and calcium in plaque biofilms after  the use of conventional and low-fluoride dentifrices.
abstract: BACKGROUND
  The distribution of fluoride and calcium in plaque after the use of fluoride dentifrices has not yet been determined.
  
  
  OBJECTIVE
  To evaluate fluoride and calcium distribution in sections of biofilms generated in situ after the use of conventional and low-fluoride dentifrices.
  
  
  METHODS
  Children (n = 11, 8–10 years old) brushed with placebo (fluoride-free), low-fluoride (513 mgF/kg), and conventional (1072 mgF/kg) dentifrices twice daily for 1 week, following a double-blind, cross-over protocol. Biofilms were generated using Leeds in situ devices, which were collected 1 and 12 h after brushing, and sectioned through their depth. Sections were grouped (10 x 5 μm) for fluoride and calcium analysis. Sections 4 lm thick were used for image analysis and determination of biomass fraction. Results were analysed by ANOVA, Tukey’s test, and linear regression analysis (P < 0.05).
  
  
  RESULTS
  Fluoride and calcium were mostly located at the outer sections of biofilms for all dentifrices tested, and these ions were directly correlated throughout most of biofilm’s sections. Results for conventional dentifrice were significantly higher than for the placebo, but did not differ from those for the low-fluoride dentifrice.
  
  
  CONCLUSIONS
  The use of a low-fluoride dentifrice did not promote a higher fluoride uptake in inner biofilms’ sections, as hypothesized. As plaque fluoride was significantly elevated only after the use of the conventional dentifrice, the recommendation of low-fluoride formulations should be done with caution, considering both risks and benefits.
authors.forename: Juliano Pelim
authors.initials: JP
authors.lastname: Pessan
authors.forename: Karina Mirela Ribeiro
authors.initials: KM
authors.lastname: Pinto Alves
authors.forename: Flávia de Moraes
authors.initials: Fde M
authors.lastname: Italiani
authors.forename: Irene
authors.initials: I
authors.lastname: Ramires
authors.forename: José Roberto Pereira
authors.initials: JR
authors.lastname: Lauris
authors.forename: Gary Milton
authors.initials: GM
authors.lastname: Whitford
authors.forename: Kyriacos Jack
authors.initials: KJ
authors.lastname: Toumba
authors.forename: Colin
authors.initials: C
authors.lastname: Robinson
authors.forename: Marilia Afonso Rabelo
authors.initials: MA
authors.lastname: Buzalaf
mesh_terms: D018441:Biofilms; D001938:Brazil; D002118:Calcium / Q000378:metabolism*; D002648:Child; D003773:Dental Plaque; D003802:Dentifrices; D005260:Female; D005459:Fluorides / Q000008:administration & dosage* / Q000378:metabolism*; D006801:Humans; D008297:Male
chemical_list: D003802:Dentifrices; D005459:Fluorides; D002118:Calcium