In vivo fluoride uptake in enamel and dentin from fluoride-containing materials.

The ability of fluoride-containing materials to deposit fluoride into the cavity walls could be a measure of their anticariogenic properties. Great penetration depths of fluoride were found in all groups in this study, with deeper penetration in dentin compared to enamel.

In vivo uptake and retention of fluoride after a brief application of TiF4 to dentin.

The purpose of this study was to examine the long-term retention of F and Ti in dentin after a brief application of 1% TiF4. Six facets of exposed dentin in each of four beagle dogs were treated for 10 sec or 1 min with a 1% solution of TiF4. Four control facets in a fifth dog were left untreated and extracted after 12 weeks. The TiF4-treated teeth were harvested after 4, 8, and 22 weeks and analyzed for F and Ti with an electron microprobe. The F concentrations in dentin surfaces of specimens retained in the mouth for 4, 8, and 22 weeks were after the 10-sec treatment 0.48% +/- 0.24, 0.51% +/- 0.20, and 0.56% +/- 0.20, respectively, and after the 1-min treatment 0.64% +/- 0.20, 0.66% +/- 0.18, and 0.71% +/- 0.19. High concentrations of Ti were found at the specimen surfaces in all groups. None of the control specimens showed F or Ti contents above the detection limits for the method used. The results showed that a very brief application of 1% TiF4 deposited high concentrations of F and Ti which were retained for at least 22 weeks.

Effects of TiF4 solutions on root surfaces in vitro after different application periods.

Topical application of aqueous solutions of TiF4 to root surfaces has been shown to result in a rapid uptake of fluoride. The purpose of this study was to assess whether the application period and/or the ionic strength of the TiF4 solution can be reduced without a corresponding reduction in the fluoride uptake. Root halves from human teeth were exposed to (a) 1% TiF4 for 10 sec and 1, 2, and 4 min, and (b) 3.4% TiF4 for the same application periods. Root surface areas protected by nail polish served as controls. Transverse ground sections through the treated root surface areas were then prepared and analyzed for F by electron microprobe analysis. Most treated specimens showed F concentrations in the 0.60-1.94% range, whereas control surfaces contained less than 0.30%. Similar F concentrations were found in the surfaces treated with the two solutions. Reducing the application period resulted in a shallower penetration of F into the hard tissue but only a slight reduction of the F concentration in the surface layer. High concentrations of Ti were found on the surface of all treated specimens. This shows that both the application period and the ionic strength of TiF4 solutions can be considerably reduced and still enable a high uptake of fluoride. The results indicate that TiF4 may be an efficacious agent for F application to root surfaces under clinical conditions.

Long-term retention of TiF4 and SnF2 after topical application to dentin in dogs.

As part of an evaluation of the potential of topical application of TiF4 in the prevention or arrest of root caries, the longevity of the titanium-rich glaze and the long-term retention of titanium and fluoride in exposed dentin surfaces were examined in dogs. For comparison, the effect of fluoride in combination with another cation, tin, was studied as well. Facets of exposed dentin were prepared in two beagles and treated for 1 or 4 min with either a TiF4 or an SnF2 solution (1.1 M F, native pH). After 3, 7, or 21 wk, the experimental surfaces were analyzed for fluoride, titanium, tin, and calcium using an electron microprobe. Dentin surfaces treated with TiF4 for 1 min showed fluoride concentrations ranging from less than 0.15% to 1.03%, while those treated for 4 min with SnF2 showed values from 0.22% to 1.28%. The calcium analyses revealed partial surface demineralization in one half of the SnF2-treated specimens, while this was a rare finding in the TiF4 group. The findings show that a brief application of TiF4 to exposed dentin results in approximately the same increase in fluoride content as a 4-min application of SnF2, with, however, less surface demineralization. In addition, the presence of a surface glaze may impart an added benefit to the use of TiF4 as a topical agent in the prevention of root caries.

X-ray microanalysis of dentin: a review.

The aim of this review was to present a condensed summary of the literature on X-ray microanalysis of dentin, including both energy-dispersive (EDS) and wavelength-dispersive (WDS) analysis. Estimations of concentrations by XMA of dentin should be regarded as semiquantitative values. The Ca level in rat odontoblasts was elevated in the secreting end of the cell body. In predentin Ca accumulated at a concentration of 2% that of mineralized dentin. In coronal dentin the peritubular areas were hypermineralized (Ca, P, Mg). Primary caries lesions showed a decrease of Ca, P, Mg and Cl, and usually an increase of S and Zn. The mineralized surface often present contained especially high concentrations of F and K. Considerable uptake of various ions in cavity walls exposed to filling materials was assessed: from silver amalgam, Zn and Sn, from silicate cement and glassionomer cement F, Al and Zn, and from zinc oxide-eugenol cement, Zn. The highest F concentrations following topical application were found with solutions of TiF4 and with the varnishes Duraphat and Fluor Protector. Dentin wall lesions adjacent to amalgam fillings exhibited considerably reduced Ca and P values, but concomitantly considerable amounts of Zn and Sn, that explained the increased radiopacity seen in some microradiographs.

Electron probe study of coronal dentin in red deer.

A topographic description of the concentration profiles of Ca, P, Mg, Zn, F, S and K in coronal dentin of red deer is given. The concentrations reported should be regarded as semiquantitative values. An area along the mesiodistal axis of the crowns showed lower concentrations of Ca and P and higher concentrations of Mg than the surrounding bulk of dentin. The inner dentin revealed downward slopes of the Ca, P and Mg profiles toward the pulpal cavity, whereas the Zn, F and usually also the S profiles showed elevations. Incidental findings were elevations of S and K profiles near the worn incisal edges. The walls of giant tubules, which are frequent in red deer dentin, showed in many cases modest elevations of the Ca, P, Mg and Zn profiles. The lumina of these tubules revealed in a few instances elevation of the S profiles.

Electron probe study of human and red deer cementum and root dentin.

A topographical description of the concentration profiles of Ca, P, Mg, Zn, F, S, and K in human and red deer cementum and root dentin is given. The concentrations reported should be regarded as semiquantitative values. A downward slope of the Ca, P and Mg profiles toward the pulpal cavity seemed largely to correspond with the secondary dentin. Marked elevations of the Zn profiles, modest elevations of the F profiles, and in a few instances of the S profiles, toward root surface and pulpal cavity were registered. In a couple of scans a slight elevation of the K profile toward the root surface ws observed. A high degree of concordance in human and red deer teeth was ascertained.

Fluoride uptake by cavity walls from a fluoride-containing amalgam in vitro. An electron microprobe analysis.

The aim of this study was to register the fluoride distribution in cavity walls following exposure to a fluoride-containing amalgam in vitro. Class V cavities were prepared on buccal and lingual surfaces in ten extracted premolars and filled with a fluoride-containing (experimental) or a conventional (control) amalgam. After storing the teeth in artificial saliva for three months, the fillings were removed and the cavity walls analyzed with an electron microprobe. The cavity walls which had been exposed to the conventional amalgam did not show F concentrations above the detection limit (0.15%). In the experiment group, however, more than 60% of the analyses of the enamel walls revealed fluoride concentrations greater than 0.15%, the values ranging from 0.2 to 1.7%. In the dentin walls fluoride concentrations of 0.2 - 1.9% were measured. However, 80% of the analyses revealed values between 0.9 and 1.5%. The depth of the zone of increased F concentration in enamel and dentin walls was on the average 27 and 108 micrometer, respectively. Although the concentrations should only be regarded as semiquantitative values, they indicate that considerable amounts of fluoride are deposited in the cavity walls from the fluoride-containing amalgam.