Effects of different amine fluoride concentrations on enamel remineralization.

OBJECTIVES: The aim of this study was to investigate the effects of decreasing fluoride concentrations on repeated demineralizing challenges on human enamel. MATERIALS AND METHODS: In 24 teeth, 3mm×3mm windows were prepared on the buccal and lingual sides and treated in a cycling demineralization-remineralization model. Remineralization was achieved with 100, 10 and 0.1 ppm fluoride from anime fluoride. Coronal sections were cut through the artificial lesions, and three sections per tooth were investigated using polarized light microscopy and scanning electron microscopy with quantitative element analysis. RESULTS: The morphology of the lesions was studied, and the extensions of the superficial layer and the body of the lesion were measured. Using element analysis, the Ca, P and F content were determined. The body of the lesion appeared remineralized after application of 100 ppm fluoride, while remineralization of the lesion was less successful after application of 10 and 0.1 ppm fluoride. The thickness of the superficial layer increased with decreasing fluoride concentrations, and also the extension of the body of the lesion increased. Ca and P content increased with increasing fluoride concentrations. CONCLUSIONS: The effectiveness of fluoride in enamel remineralization increased with increasing fluoride concentration. CLINICAL RELEVANCE: A consistently higher level of fluoride in saliva should be a goal in caries prevention.

Quantitative analysis of the calcium and phosphorus content of developing and permanent human teeth.

It was the aim of this study to investigate the distribution of Ca, P and C in predentin, dentin and enamel in human tooth buds and permanent teeth by EDX element analysis. The mandible of a 16-week-old human fetus containing eight mineralizing tooth buds and three human permanent molars were fixed in formaldehyde and embedded in Technovit 9100. Serial sections of 80 microm thickness of the mandible were cut in the frontal-dorsal direction, and polarized light micrographs were taken of these sections. The permanent teeth were cut in mesio-distal direction. The sections were investigated with scanning electron microscopy and EDX element analysis with a Philips XL 30 FEG scanning microscope and an EDAX energy-dispersive X-ray system using spot measurements, EDX line-scans and element mapping. Quantitative measurements were made in predentin, mineralizing dentin adjacent to predentin, mature dentin, mineralizing enamel and young enamel of developing teeth and mature enamel of permanent teeth. In developing teeth the Ca and P content increased rapidly from outer predentin towards mineralizing dentin. In enamel prisms of developing teeth the Ca and P content increased linearly from the surface towards the enamel-dentin junction. In permanent teeth only a small layer of predentin was found. The Ca and P content in enamel and circumpulpal dentin of permanent teeth was higher than in developing teeth. The Ca/P ratio differed between predentin and dentin areas reflecting different calcium phosphate compositions, but it was the same in mineralizing and young enamel. The differences in the distribution of Ca and P reflect different mineralizing patterns of the enamel and dentin matrices.

[Experimental algesimetric study of the hypoalgesic effect of body acupuncture]. / Experimentelle algesimetrische Untersuchung zum hypalgetischen Effekt der Körperakupunktur.

AIMS: The aim of the present study was to investigate whether body acupuncture is suitable to increase the pre-pain sensitivity threshold (PPST). METHODS: For this purpose, the PPST was algesimetrically determined after pulpal electric stimulation (baseline) in 24 patients with healthy frontal teeth. RESULTS AND DISCUSSION: After acupuncture at specific (test group) and unspecific sites (control group, placebo acupuncture), the shift of the PPST was registered. After stimulation of specific acupuncture sites, a mean increase of 110% of the PPST could be obtained. Stimulation at unspecific sites showed only an increase of the PPST of 30%. To which extent this pain reduction is due to a physiological effect on pain reception, or physical irritation, or suggestion could not be verified in this study. Also, the endorphin theory discussed in connection with acupuncture could neither be proved nor disproved. Further controlled clinical studies have to be carried out to prove under clinical conditions the positive results of this experimental algesimetric study.