Fluorine binding with dentin adjacent to fluoride-containing luting materials

Tooth-bound (KOH-insoluble) fluoride contributes to caries prevention because of its low acid solubility and long retention within tooth structure. The purpose of this study was to evaluate tooth-bound fluoride in dentin, taken up from fluoride-containing luting materials, using an in-air μPIXE/PIGE system. The dentin surface of tooth root cross-sections and an acrylic resin were cemented with four different fluoride-containing luting materials. Specimens were stored in a remineralizing solution for 4 or 8 weeks and then sectioned into two slices. Two adjacent slices were used for measurement of fluorine and calcium concentration using in-air μPIXE/PIGE. For analysis of the KOH-insoluble fluoride ((KOH(+)), one slice was immersed in 1 mol/L KOH solution for 24 h. The other slice was not treated with KOH in order to analyze KOH-soluble and -insoluble fluoride (whole fluoride, KOH(−)). KOH(+) levels were lower than KOH(−) levels for all materials at both duration periods. Higher concentration of fluorine wa...