title: In vitro effect of calcium nanophosphate and high-concentrated fluoride agents on enamel erosion: an AFM study.
abstract: BACKGROUND
  Calcium nanophosphate paste can provide ions to remineralize enamel. There are, however, no data available about the remineralizing effect of this paste on the prevention of enamel erosion, when compared with highly concentrated fluoride agents.
  
  
  OBJECTIVE
  To analyze the effect of calcium nanophosphate paste, fluoride gel, and varnish to protect against enamel erosion using surface Knoop hardness (KNH) and atomic force microscopy (AFM).
  
  
  METHODS
  Forty enamel blocks (4 × 4 mm) of third molars were used for 4 groups (n = 10): 1.23% fluoride gel (Fluorgel-DFL(®) ); calcium nanophosphate paste (Desensibilize NanoP-FGM(®) ); fluoride varnish (Duraphat-Colgate(®) ) and control (without agent). The specimens were immersed in cola drink for 5 min and 2 h in artificial saliva, 4× per day for 5 days. The agents were applied before the first erosive cycle. KNH values were obtained before and after the erosive challenge. The surface morphology was evaluated by AFM. anova, Tukey's, and T-Student tests were applied.
  
  
  RESULTS
  After erosion, no significant difference was found for KNH among gel, nanophosphate, and varnish groups; however, they showed higher KNH than control group. Gel and nanophosphate paste showed a protective layer formation on enamel surface by AFM.
  
  
  CONCLUSIONS
  The calcium nanophosphate paste showed similar protection against enamel erosion compared with high-concentrated fluoride agents, even containing lower fluoride concentration.
authors.affiliation: Department of Dentistry, Federal University of Campina Grande, UFCG, Patos, PB, Brazil.
authors.forename: Isabella Cavalcante
authors.initials: IC
authors.lastname: Medeiros
authors.forename: Veruska Lima Moura
authors.initials: VL
authors.lastname: Brasil
authors.forename: Hugo Lemes
authors.initials: HL
authors.lastname: Carlo
authors.forename: Rogerio Lacerda Dos
authors.initials: RL
authors.lastname: Santos
authors.forename: Bruno Alessandro Silva Guedes
authors.initials: BA
authors.lastname: De Lima
authors.forename: Fabíola Galbiatti
authors.initials: FG
authors.lastname: De Carvalho
mesh_terms: D002130:Calcium Phosphates / Q000737:chemistry*; D003743:Dental Enamel / Q000737:chemistry*; D005459:Fluorides / Q000737:chemistry*; D006801:Humans; D066298:In Vitro Techniques; D018625:Microscopy, Atomic Force; D053758:Nanoparticles; D014077:Tooth Erosion
chemical_list: D002130:Calcium Phosphates; C020243:calcium phosphate; D005459:Fluorides