The caries-inhibiting effect of unsupervised daily use of four different toothpastes was compared in a 3-year clinical and microbiological study: (1) 0.8% sodium monofluorophosphate (MFP) with 3% xylitol and 6% sorbitol; (2) 0.03% sodium fluoride with 3% xylitol and 6% sorbitol; (3) 0.8% MFP with 9% sorbitol, and (4) 0.03% sodium fluoride with 9% sorbitol. In all 284 children, 12–13 years old at baseline, took part in the study. After 3 years, no statistically significant differences were found between the different toothpaste groups concerning either development of initial or gross caries lesions or number of mutans streptococci and lactobacilli in saliva. However, children with no detectable approximal caries at baseline, who used the MFP toothpaste with the xylitol-sorbitol mixture, showed a lower (p < 0.05) caries increment as compared with children who used the MFP toothpaste with sorbitol alone.

The aim of this study was to compare the effect of two different dental varnishes on approximal caries incidence in teenagers with proven caries susceptibility during a 3–year period. Two hundred 13– to 14–year–old subjects exhibiting at least two approximal enamel caries lesions were selected to take part in the study. One hundred and eighty subjects participated after informed consent and were randomly assigned to two equally sized groups. One group was treated with a fluoride varnish (FV, Fluor Protector) containing 0.1% F every 3rd month and the participants of the other group were treated in the same mode with a chlorhexidine varnish (CV, Cervitec^®) containing 1% chlorhexidine and 1% thymol. In total, each subject was treated 12 times during the experimental period. Approximal caries including enamel lesions (DMFS_appr) were recorded from four bitewing radiographs exposed at the start and end of the study. The mean (±SD) caries prevalence at baseline was 2.2±3.4 in the FV group and 2.5±4.0 in the CV group. After 3 years, the average approximal caries incidence was 2.7±3.1 and 3.1±3.5 in the FV and CV groups, respectively. The differences at baseline and after 3 years were not statistically significant. In conclusion, treatments every 3rd month with either a fluoride– or a chlorhexidine/thymol–containing varnish showed a promising effect with low approximal caries incidence and progression in teenagers with proven caries suceptibility.

The penetration profiles of F have been investigated using secondary ion mass spectrometry, at depths of ca. 0.1–1.5 μm in specimens of permanent and deciduous human enamel after application of different varnishes and toothpastes. The treatment with NaF containing varnishes was found to result in gains of more than 1,000 wt-ppm F even at 1.5 μm depth, roughly proportional to the root of the fluoride content in the agent. Silane varnish yields similarly high F uptake and a particularly flat penetration profile. While F from the NaF varnish in the main seems to enter the dental tissue, that from the silane to a large extent remains in the agent medium, penetrating the porosities of enamel. Some evidence is seen of a chemical transformation of superficial enamel in the presence of the silane agent. Acidulated NaF toothpastes yield considerably higher and flatter F penetration profiles than all neutral or basic toothpastes investigated.

A Cameca IMS 300 ion analyzer has been used to measure fluorine concentrations in tooth material. Samples of human and shark teeth were studied. Negative oxygen primary ions produce secondary mass spectra in which positive as well as negative fluorine ion peaks are well re­ presented. With constant measuring conditions, the reproducibility of the F/Ca ion ratios is satisfactory. Fluorine concentrations in the 10 ppm region are easily recorded. By means of samples previously measured by macroscopic F-determining methods, a calibration can be effected to obtain, from the ion current ratios, at least semiquantitative values of F-concentrations. In a sample of human enamel, the F-concentration was found to vary from about 3000 ppm at the surface to about 100 ppm in the interior. In shark enamel the composition at the surface cor­ responded to nearly saturated fluorapatite, 3.6% F, but the fluorine concentration decreased distinctly at increasing depth.