Enamel Fluoride Retention after DCPD and APF Application and Prolonged Exposure to Fluoride in vitro

Abstract

The effect of a topical fluoride regimen consisting of a four-minute pre-treatment with a saturated dicalcium phosphate dihydrate (DCPD) solution followed by a four-minute application of APF was compared with that of a four-minute application of APF alone with respect to the deposition of fluoride in enamel in an apatitic form in vitro. Following the topical applications, specimens were washed in either (1) an inorganic wash solution for 24 hrs or (2) an inorganic wash solution with 1 ppm F added for 28 days; specimens were then subjected to KOH extraction for 24 hrs. Fluoride-by-depth profiles revealed that the DCPD/APF treatment resulted in a significant increase in the apatitic F concentration of enamel to a depth of 20 microns, while APF application alone did not. All groups exposed to the 1 ppm F wash acquired significant amounts of apatitic F, with the differences between groups remaining relatively constant.

Enhanced Enamel F Uptake by Monocalcium Phosphate Monohydrate Gels

“…The F uptake by the control specimens observed in the present study is consistent with previously reported results in which the enamel was treated with a 1-or 2-ppm-F solution of similar composition (ten Cate and Duijsters, 1982;Crall and Bjerga, 1986). Other in vitro studies (Hong et al, 1985) and in vivo studies (Mellberg and Nicholson, 1974;Shern et al, 1984) have shown that repeated short applications of 0.2% NaF can cause incorporation of some permanently bound F into the enamel.…”

“…The 1 ppm F solution used in the present study has calcium and phosphate concentrations similar to those in saliva, but the F concentration, 1 or 2 ppm, used here as well as in several other studies (ten Cate and Duijsters, 1982;Crall and Bjerga, 1986), is considerably higher than that found in saliva. However, enamel pre-treated with DCPD-forming solution has been shown (Takagi et al, 1984) to be capable of incorporating F from solutions containing as low as 0.1 ppm F in vitro, whereas enamel not pre-treated was unreactive with F of this level.…”

“…Application of DCPD-forming solutions has been shown to increase substantially the enamel reactivity toward F (Takagi et al, 1984;Bjerga and Crall, 1984;Crall and Bjerga, 1986;Shem et al, 1984;Hong et al, 1985). Thus, if F is available from sources such as F-containing dentifrices or rinses, the apatitic F content in enamel can be increased by the use of DCPD-forming treatments without additional topical F applications.…”

Assessment of Loosely-bound and Firmly-bound Fluoride Uptake by Tooth Enamel from Topically Applied Fluoride Treatments

“…The very low F uptake values determined from the enamel biopsy data for the APF-treated samples would suggest that in the present study, little (if any) CaF2 remained in the enamel after the washing. In contrast to the APF treatment, the combination of DCPD and APF treatments produced a much greater firmly-bound F uptake, as has been shown previously (Chow et al, 1981;Crall and Bjerga, 1986). The DCPD pre-treatment appeared to be a beneficial adjunct to the F treatment, because it promoted the deposition of both loosely-bound and firmly-bound F uptake.…”

Enhanced Root Fluoride Uptake by Monocalcium Phosphate Monohydrate Gels

“…The results obtained in the present study are consistent with those reported previously [Crall and Bjerga, 1986;Takagi et al, 1987] in that an acidic pretreatment which formed DCPD in the enamel mineral increased the F incorporation. Formation of DCPD has also been suggested [Chow and Brown, 1975] as a possible mechanism for the increased F uptake induced by acid pretreatment [Aasenden et al, 1968], Although the MCPM gel also contained some F, nearly all of the F was in the undis solved form of CaF?…”