Enamel Dissolution: II. Action of Titanium Tetrafluoride

Abstract

Mechanisms by which titanium tetrafluoride (TiF4) reduces enamel solubility were investigated. An association was found between solubility reduction and the formation of a glaze on the enamel surface. Also, TiF4-treated enamel had higher levels of fluoride than enamel treated with acidulated phosphate-sodium fluoride. Solubility reductions and fluoride levels decreased slightly with washing but after 48 hours the fluoride level was still 60% of the maximum, and solubility reductions ranged between 64 and 70%.In previous work,' it was shown that titanium tetrafluoride (TiF4) treatment of enamel gave greater reductions of enamel solubility and greater protection against animal caries than did comparable use of other fluorides. These indications of the potential caries-preventive value of TiF4 prompted further study of its effects on enamel. During these latter studies, we observed that TiF4-treated enamel often acquired a glazelike appearance. This raised the question of the extent to which the uniquely high solubility-reducing effect of TiF4 might be dependent on reactions associated with the "glaze" formation or on the fluoride content of TiF4-treated enamel.To obtain information on these questions, experiments were undertaken to indicate the conditions under which the TiF4 glaze formed on enamel, the fluoride content of TiF4-treated enamel, and the relationship of these to the observed reductions in enamel going into solution. Materials and MethodsIn vitro effects on enamel dissolution were measured by the previously described' 'window' technique, in which windows made on unground bovine enamel surfaces are exposed to a series of 15-minute acid decalcifixations in 20 ml 0.1 M acetic acid buffer (HAc), pH 4. The difference in amounts of phosphorus2 in the decalcifying buffer before and after treatment of the enamel with TiF4 or other agents gave a measurement of effects on enamel solubility.The glaze that appeared on the enamel, particularly after topically applied TiF4 followed by application of 0.1 M HAc, was given a visual rating of from 0 to ++++. This glaze produced seemingly whiter enamel and appeared on ground and unground human enamel, and on unground bovine enamel surfaces.To obtain information on the factors influencing glaze formation and the extent to which the glaze determined solubility reduction, glazes of different grades (0 to ++++) formed under various conditions were compared with solubility findings. For this purpose, different agents were used with TiF1 on normal bovine enamel, ethylenediamine-extracted "anorganic" enamel, and "organic-exposed" enamel. The ethylenediamine (ED)-extracted enamel was prepared by refluxing for 2.5 or 20 hours in a Soxhlet apparatus at 118 C.3 Organic-exposed enamel refers to the incompletely EDextracted enamel4 that was etched for two minutes with 0.3%l HCl, thereby exposing the underlying organic material in the partially anorganic enamel. Solubility changes were measured by the window technique.To indicate whether the high solubility reductions given by TiF4, w...

The In Situ Effect of Titanium Tetrafluoride Gel on Erosion/Abrasion Progression in Human Dentin

“…The matrix, even though suggested to be removed prior to laboratorial analysis (17), may have been important to inhibit the progression of erosive lesions, especially when treated with TiF 4 . Some authors reported that TiF 4 produces a glaze on the dentin surface (6,18) and one of the strongest actual theories to explain this formation considers the direct interaction between titanium and the organic matrix (8).…”

“…Among the existing theories to explain its action, one is that titanium is capable of reacting with the oxygen atoms of the phosphate groups of the dental tissue, forming stable titanium oxides (7) or organometallic complexes that can act as a diffusion barrier (8).…”

Protection of short-time enamel erosion by different tetrafluoride compounds

“…6,8,12 The protective effect of TiF 4 is attributed to the acid-resistant surface coating formed by the fluoride-metal complex, which might lead to a mechanical protection of the surface. 14 Furthermore, the application of TiF 4 might lead to an increase in the enamel fluoride content.…”

“…This might enhance the depth of penetration of fluoride ions and promote the formation of CaF 2 . The titanium ions might play an important role as they might substitute calcium in the apatite lattice and show a strong tendency to complex with phosphate groups, forming stable titanium dioxide layer [14][15][16] . Moreover, it is suggested that titanium interacts with organic components of the enamel surface, leading to an increased fluoride uptake by enamel.…”

“…Moreover, it is suggested that titanium interacts with organic components of the enamel surface, leading to an increased fluoride uptake by enamel. 14,17 However, Mundorff et al 14 suggested that hafnium and zirconium might be unable to form an acid-stable surface glaze. In contrast, by SEM analysis it could be shown that pretreatment of enamel surface with different polyvalent ions followed by application of acidulated phosphate fluoride lead to the formation of an amorphous coating on the enamel surface.…”