The aim of this study was to develop a titanium tetrafluoride (TiF 4 ) 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)54؍ were aged at 65°C and 30% of relativity humidity (RE n°0 1/05-ANVISA) and after 3, 6, 9 and 12 months, nine samples were removed for evaluation and compared with fresh samples. Chemical stability of TiF 4 varnish was determinate by , respectively. Means followed by distinct letters were statistically different (pϽ0.05). 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 CaF 2 .Key words titanium tetrafluoride; drug stability; fluoride varnish Although professionally applied topical fluoride treatment has been used for caries control for many years, there is an interest in finding new compounds for this purpose.1,2) TiF 4 (titanium tetrafluoride) is a fluoridated compound which has low values of pH (ca. 1-2) 3) in water or alcohol solutions. In addition to the pH values, titanium corrosion resistance and the capacity to form an oxide coating on enamel could be responsible for the results related to caries process.
1,2,4-7)However, in spite of the promising results, this compound has not yet been used in clinical procedures due to the lack of stability in water solutions.
8)TiF 4 hydrolysis processes in water have been described, with emphasis on the formation of many fluoride complexes. 4,6) In addition to the stability and physical chemical properties of fluoridated agents, the efficacy of these products depends on the capacity to react with enamel forming reaction products, which can be loosely (calcium fluoride) or firmly (fluorapatite) bound to enamel and could interfere with the de-and re-mineralizing phases of the caries process.7) The aim of this study was to produce a TiF 4 varnish and evaluate the chemical stability and enamel reactivity during one year period.
ExperimentalVarnish Preparation and Aging The TiF 4 varnish was prepared by dissolving TiF 4 (ca. 4%) and resin products in ethanol 96%. A homogeneous solution was obtained by slowly adding the solids to ethanol with vigorously stirring. Next, the viscous solution was placed in plastic containers (nϭ45), protected from light exposure and maintained in an aging process at 65°C and 30% RH (relative humidity). 9) After 3, 6, 9 and 12 months, nine samples were removed for analyses and compared with fresh samples.NMR Spectra The fresh and aged TiF 4 varnish formulations were analyzed by 19 F-NMR using a Bruker AC300 (282.4 MHz) and an Advance DPX (235.4 MHz) spectrometer in 5 mm co-axial tubes at Ϫ30°C. CFCl 3 was placed in the center coaxial tube as a chemical shift reference (dϭ0 ppm) and as a reference for quantitative analyses.Reactivity with Enamel The reactivity of the TiF 4 varnish formulation was evaluated using 15 bovine enamel blocks (3ϫ3ϫ2 mm) per group/time. A varnish without T...