PubMed · 15400384
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P RENARD. 1950. The fluoride issue.. https://pubmed.ncbi.nlm.nih.gov/15400384/
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OBJECTIVES: The uptake of F(-) ions by glass ionomer cement (GIC) has been extensively studied but the precise location of the F(-) ion in the GIC structure has not been reported. The aim of this study is to use model materials to elucidate the possible locations. GIC consists of residual particles of aluminosilicate glass surrounded by depleted glass in an ionically crosslinked polymeric matrix. This study evaluates uptake by both unreacted glass particles (RAW) and particles acid-treated to produce a depleted glass surface (DEPLETED). METHOD: Three glasses, previously studied as cements, were tested at the particle size used in GICs. LG30 contained Al, Ca, O, P, and Si; LG26 also contained F and AH2 contained Na as well. To produce depleted surfaces they were immersed in acetic acid washed and dried at room temperature. Test samples (N=5) were immersed in KF solution (900ppm F). Control solutions without glass were used. Both were stored at 37C for 48h. F concentrations were measured using ISE with TISAB IV. RESULTS: Uptake was Control-test expressed in micromol/g glass. RAW LG30=56 (16); LG26=35(17); AH2=17(31). DEPLETED LG30=285(41); LG26=431(42); AH2=286(50). The levels of F uptake by DEPLETED were comparable to those found with GICs formed with these glasses. CONCLUSIONS: The glass particles of GIC, and particularly the depleted zones surrounding them, can account for an appreciable amount of the F uptake observed with cements but do not show the same relation between F content and F uptake previously observed with cements.
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We demonstrate a multi-spectrum technique for facile, quantitative determination of lead in solid materials using solid-state (207)Pb NMR that avoids the major problem of uniform excitation across a wide spectral range; the method can be employed without chemical separation or other chemical manipulations and without any prior sample preparation, resulting in a non-destructive analysis, and producing results that are in agreement with gravimetric analyses of mixed samples of the lead halides.