Formation of CaF2 on sound enamel and in caries-like enamel lesions after different forms of fluoride applications in vitro.
The formation of calcium fluoride (CaF2) was measured on sound enamel (SE) and in caries-like enamel lesions (CL) after treatment in vitro with 2% neutral NaF or Duraphat. The caries-like lesions were created by exposure to acidified gel at pH 4.5 within a 0.07-cm2 window punched in water-repellant tape. The same window area was used in series (n = 10) of SE or CL during the application of NaF for 1 or 5 min or for 18 h or Duraphat for 6 or 18 h. CaF2 was extracted with 1 M KOH for 24 h, and fluoride was determined by gas chromatography. The short-term applications of NaF produced only negligible amounts of CaF2 on SE. The amounts of CaF2 in CL after 5 min application of NaF corresponded to (mean +/- SEM) 27 +/- 2.0 micrograms F/cm2. More than half of this amount was observed after only 1 min exposure to the NaF solution. The quantities of CaF2 in CL were similar after 6 and 18 h application of Duraphat, amounting to 26 +/- 2.2 and 31 +/- 2.2 micrograms F/cm2, respectively, suggesting that the reaction was essentially terminated after 6 h. These amounts were only about one fourth of the quantity obtained after 18 h exposure to the NaF solution. Thus, the conventional 5-min treatment with NaF produced the same amount of CaF2 in CL as 6 or 18 h exposure to Duraphat.
Bruun
C
C
Department of Cariology and Endodontics, Royal Dental College, Copenhagen, Denmark.
Givskov
H
H
D002124:Calcium Fluoride / Q000032:analysis* / Q000378:metabolism; D003731:Dental Caries / Q000378:metabolism*; D003743:Dental Enamel / Q000378:metabolism*; D003747:Dental Enamel Solubility; D005460:Fluorides, Topical / Q000008:administration & dosage*; D006801:Humans; D016062:Porosity; D012969:Sodium Fluoride
D005460:Fluorides, Topical; C023807:sodium fluoride topical preparation; D012969:Sodium Fluoride; D002124:Calcium Fluoride