TiF4 varnish-A F-19-NMR stability study and enamel reactivity evaluation

The aim of this study was to develop a titanium tetrafluoride (TiF4) varnish and evaluate the stability of the formulation and its reactivity with dental enamel. The varnish was prepared in a resinous matrix using ethanol 96% as solvent. Samples (n=45) were aged at 65 degrees C and 30% of relativity humidity (RE no 01/05-ANVISA) and after 3, 6, 9 and 12 months, nine samples were removed for evaluation and compared with fresh samples. Chemical stability of TiF4 varnish was determinate by F-19-NMR and the reactivity of the formulation was quantified by formation of fluoride loosely (CaF2) and firmly bound (fluorapatite; FA) to enamel. For reactivity comparisons, a varnish without TiF4 was used as control. The loss of soluble fluoride was about 0.9% after one year of storage. The values of the reactivity (mean +/- S.D.) of fresh, aged at 3, 6, 9 and 12 months and control samples were: CaF2 (mu g F/mm(2)) : 89.3 +/- 27.5(a); 54.5 +/- 14.3(b); 51.2 +/- 29.8(b); 69.3 +/- 21.3(a); 48.0 +/- 27.4(b); 0.10 +/- 0.07(c), FA (mu g F/g): 2477.5 +/- 1044.0(a); 2484.8 +/- 992.0(a); 2580.0 +/- 1383.9(a); 2517.2 +/- 929.9(a); 2121.0 +/- 1059.2(a); 330.0 +/- 180.0(b), respectively. Means followed by distinct letters were statistically different (p<0.05). After one year of storage, the formulation was chemically stable and the levels of FA were maintained. However there was an initial decrease in the ability to form CaF2.