Mechanism of Action of TiF₄ on Dental Enamel Surface: SEM/EDX, KOH-Soluble F, and X-Ray Diffraction Analysis

Abstract

This in vitro study aimed to evaluate the action of TiF₄ on sound and carious bovine and human enamel. Sound (S) and pre-demineralised (DE) bovine and human (primary and permanent) enamel samples were treated with TiF₄ (pH 1.0) or NaF varnishes (pH 5.0), containing 0.95, 1.95, or 2.45% F for 12 h. The enamel surfaces were analysed using SEM-EDX (scanning electron microscopy/energy-dispersive X-ray spectroscopy) (n = 10, 5 S and 5 DE) and KOH-soluble fluoride was quantified (n = 20, 10 S and 10 DE). Hydroxyapatite powder produced by precipitation method was treated with the corresponding fluoride solutions for 1 min (n = 2). The formed compounds were detected using X-ray diffraction (XRD). All TiF₄ varnishes produced a coating layer rich in Ti and F on all types of enamel surface, with micro-cracks in its extension. TiF₄ (1.95 and 2.45% F) provided higher fluoride deposition than NaF, especially for bovine enamel (p < 0.0001). It also induced a higher fluoride deposition on DE samples compared to S samples (p < 0.0001), except for primary enamel. The Ti content was higher for bovine and human primary enamel than human permanent enamel, with some differences between S and DE. The XRD analysis showed that TiF₄ induced the formation of new compounds such as CaF₂, TiO₂, and Ti(HPO₄)₂·H₂O. In conclusion, TiF₄ (>0.95% F) interacts better, when compared to NaF, with bovine and human primary enamel than with human permanent enamel. TiF₄ provoked higher F deposition compared to NaF. Carious enamel showed higher F uptake than sound enamel by TiF₄ application, while Ti uptake was dependent on the enamel condition and origin.

Comparison between micro‐computed tomography and transverse microradiography of sound dentine treated with fluorides and demineralized by microcosm biofilm

“…Previous works have shown that the effect of TiF 4 varnish is superior to that of NaF varnish on enamel de‐remineralization , as a result of the formation of a glaze‐like layer that is rich in calcium fluoride, titanium oxide, and hydrated titanium phosphate, which is acid resistant . Titanium tetrafluoride varnish also promoted higher deposition of calcium fluoride than NaF varnish as a result of its lower pH . Besides, TiF 4 varnish has cytotoxic potential on fibroblasts similarly to NaF varnish, which is widely applied in the mouth .…”

Effect of a Titanium Tetrafluoride Varnish in the Prevention and Treatment of Carious Lesions in the Permanent Teeth of Children Living in a Fluoridated Region: Protocol for a Randomized Controlled Trial

“…Several in vitro and in situ studies have shown that an experimental 4% TiF 4 is more effective than NaF at reducing demineralization and improving remineralization [ 7 - 9 ]. The titanium ions from TiF 4 react with dental apatite, forming an acid resistant, glaze-like layer that is rich in hydrated titanium phosphate and titanium dioxide [ 10 ]. Furthermore, TiF 4 varnish induces a higher deposition of calcium fluoride (CaF 2 ) than NaF varnish on both intact and demineralized enamel surface [ 10 ].…”

“…The titanium ions from TiF 4 react with dental apatite, forming an acid resistant, glaze-like layer that is rich in hydrated titanium phosphate and titanium dioxide [ 10 ]. Furthermore, TiF 4 varnish induces a higher deposition of calcium fluoride (CaF 2 ) than NaF varnish on both intact and demineralized enamel surface [ 10 ].…”

Avaliação dos efeitos promovidos pela aplicação do TiF4 sobre a dentina humana erodida

“…É consenso na literatura que o tetrafluoreto de titânio possui propriedades singulares quando aplicado sobre a superfície dental. Pela afinidade entre os íons Ti e o tecido dental, além da formação de compostos CaF 2 -like comum a todos os fluoretos , o TiF 4 é capaz de formar uma camada adicional sobre a superfície, conhecida como glaze Comar et al, 2017). Esta é ácido-resistente e pode proteger a estrutura recoberta do contato direto com os desafios erosivos, sejam de origem intrínseca ou extrínseca .…”