1179 Effect of Fluoride, Calcium and Phosphate on Releases from Varnishes

Saturday, March 24, 2012: 8 a.m. - 9:30 a.m.
Presentation Type: Oral Session
M. TUNG, NIST, Gaithersburg, MD, and A. CHUANG, Brown University, Providence, RI
Fluoride (F) varnishes are effective in preventing caries and reducing dentin sensitivity. The addition of calcium (Ca) and phosphate (PO4) salts may influence the F release rate and also induce formation of calcium/phosphate/fluoride as persistent F reservoirs. The hypothesis is that F release rate can be optimized with the F content and the addition of Ca and PO4 salts.  Objectives: To study the effect of the F content and the Ca and PO4 salts on the ion release and precipitation of F varnishes. Methods: The varnish containing 1670 ppm or 22600 ppm fluoride with or without Ca salt (10%) and PO4 salt (5.8%) was painted on a 2x2 cm plastic substrate and immersed in a 0.03 mol/L NaCl solution (n=3). The released ions were measured with pH, Ca, and F electrodes under slow stirring at 22 oC for 3 days. The concentrations of Ca and PO4 were analyzed by spectrophotometric methods. The precipitated calcium phosphate fluoride was characterized with X-ray Powder Diffraction and Scanning Electron Microscope.  Results: Table shows the % ± S.D. of released F; the releases increased with the increase in F content and addition of Ca and PO4 salts.







1 Day

5.1 ± 3.3%

17.3 ± 1.6%

9.6 ± 4%

41 ± 15%

3 Day

9.7 ± 7.3%

51.1 ± 5.6%

28 ± 14%

79 ± 14%

With  F-varnishes containing Ca/PO4, the Ca and PO4 concentrations increased together with the pH increase and then decreased due to the precipitation of spherical calcium fluoride and amorphous calcium phosphate nanoaggregates.  Conclusions: The release rate of F can be optimized with the F content and the addition of Ca and PO4 salts in the varnish.  These salts may prolong the retention of the released F by the precipitation of mixed phases of calcium phosphate fluorides. 

This abstract is based on research that was funded entirely or partially by an outside source: NIST and ADAF

Keywords: Caries, Delivery systems, Dental materials, Fluoride and Remineralization