TiF4 and NaF at pH 1.2 but not at pH 3.5 are able to reduce dentin erosion

Objective

This study aimed to analyse and compare the protective effect of buffered (pH 3.5) and native (pH 1.2) TiF₄ in comparison to NaF solutions of same pH on dentin erosion.

Design

Bovine samples were pretreated with 1.50% TiF₄ or 2.02% NaF (both 0.48 M F) solutions, each with a pH of 1.2 and 3.5. The control group received no fluoride pretreatment. Ten samples in each group were eroded with HCl (pH 2.6) for 10 × 60 s. Erosion was analysed by determination of calcium release into the acid. Additionally, the surface and the elemental surface composition were examined by scanning electron microscopy (two samples in each group) and X-ray energy-dispersive spectroscopy in fluoridated but not eroded samples (six samples in each group). Cumulative calcium release (nmol/mm²) was statistically analysed by repeated measures ANOVA and one-way ANOVA at t = 10 min.

Results

TiF₄ and NaF at pH 1.2 decreased calcium release significantly, while TiF₄ and NaF at pH 3.5 were not effective. Samples treated with TiF₄ at pH 1.2 showed a significant increase of Ti, while NaF pretreatment increased F concentration significantly. TiF₄ at pH 1.2 led to the formation of globular precipitates occluding dentinal tubules, which could not be observed on samples treated with TiF₄ at pH 3.5. NaF at pH 1.2 but not at pH 3.5 induced the formation of surface precipitates covering dentinal tubules.

Conclusion

Dentin erosion can be significantly reduced by TiF₄ and NaF at pH 1.2, but not at pH 3.5.