OBJECTIVE: To evaluate the in vitro preventive effect of topical application of achemically stable titanium-tetrafluoride (TiF4) varnish and a sodium fluoride (NaF) varnish on bovine enamel by pH cycling test. METHODOLOGY: The sample consisted of 75 blocks of bovine enamel measuring 3x3mm, which were randomly assigned to 5 groups of 15, as follows: G1: Fluoridated dentifrice + varnish without active principle; G2: fluoridated dentifrice + TiF4 varnish (4 minutes); G3: fluoridated dentifrice + TiF4 varnish (24 hours); G4:fluoridated dentifrice + NaF varnish (24 hours); G5: fluoridated dentifrice.A pH cycling was carried out for a period of 14 days, consisting of 8 cycles at 37 °C. The treated blocks were kept in demineralizing and remineralizing solutions for 8 and 16 hours, respectively, being then subjected to surface analysis under scanning electron microscopy and dispersive energy spectroscopy. RESULT: The TiF4 varnishshowed a greater protection to enamel when compared with the other groups.Even after the cycling period, the following elements were found on the enamel surface: phosphorus, calcium, sodium, magnesium, titanium, chlorine, silicon, aluminum, sulfur, potassium, oxygen and fluorine. CONCLUSION: The adamantine structure subjected to the action of titanium tetrafluoride revealed the presence of a protective pellicle.Calcium and phosphorus were the major inorganic compounds found in enamel. Furthermore, there were changes in the chemical composition of the adamantine surface layer as a result of the treatment with fluoride.
Titanium; fluorine compounds; reactivity-stability