Effect of a fluoridated food item on enamel in situ.

After the consumption of food items prepared with fluoridated salt elevated fluoride concentrations can be observed in saliva, whereby enamel mineralization is supposed to be positively affected. The aim of this double-blind (with respect to fluoride), placebo-controlled, randomized, cross-over study was to evaluate the effects of the consumption of either a fluoridated (effect) or a placebo food item on the mineral content of sound and pre-demineralized human enamel in situ. During both phases of the study 8 enamel specimens in each of 10 intraoral appliances were positioned, either recessed or flush with the acrylic surface. One of the flanges was brushed twice daily with fluoride-free toothpaste prior to the storage of the appliance in sucrose solution. The subjects were asked to refrain from other sources of fluorides except for the consumption of either a highly fluoride-containing (0.5 mg) or a placebo cookie (3 times daily) during the respective study phase. Mineral content and lesion depth were measured in the enamel specimens and fluoride concentrations in saliva and urine. Significantly increased urinary and salivary (immediately after food consumption) fluoride concentrations compared to baseline were observed during the effect phase. In the absence of fluorides more pronounced demineralization was observed, especially for the recessed specimens of both surface conditions. Brushing was shown to inhibit demineralization, particularly during the placebo phase. In conclusion, fluorides added to food items seem to be efficacious to inhibit enamel demineralization in plaque-covered enamel but might be less effective if oral hygiene is adequate.

Effect of various Ca2+/PO4(3-) concentrations of linseed-based saliva substitutes on enamel in vitro.

Remineralization might be hampered by various polymers used in saliva substitutes. Thus, the present study evaluated the effects of various calcium and phosphate concentrations of linseed-based solutions on the mineral loss of pre-demineralized bovine enamel in vitro. A commercially available saliva substitute (Salinum) based on linseed was tested as well. Enamel specimens were prepared from bovine incisors and embedded in epoxy resin. One-third of each sample was covered with nail varnish (control of sound enamel). After demineralization (37 degrees Celsius; pH 5.0; 14 days) another third of the samples was nail-varnished again. Subsequently, the specimens (n = 10) were exposed to 12 linseed-based solutions (Ca(2+) addition 0-2 mM; PO4(3-) addition 0-3.2 mM) at pH 5.5 and 6.5 as well as to Salinum) for 14 days (37 degrees Celsius). The differences in mineral loss between the values prior to and after the storage in the various solutions were evaluated from microradiographs of thin sections (100 mum). The general linear model revealed a significant dependency for the mineral loss on 'calcium' (P = 0.003), but not on 'pH' (P = 0.397) and 'phosphate' (P = 0.094). Salinum) induced a significant greater mineral loss compared with equivalently saturated solutions (P < 0.05; anova, Bonferroni). The solution with the highest calcium and phosphate concentration showed the greatest mineral gain (P = 0.033; paired t-test). The addition of calcium and phosphate seems to have a positive effect on the remineralizing qualities of linseed-based saliva substitutes.

Plaque surface area after rinsing with a low-level fluoride-containing Darjeeling tea.

Plaque surface area after rinsing with a tea, containing low levels of fluoride, was evaluated in 30 human volunteers with a single-blind, one-operator, three-period, three-treatment cross-over study. The mouthwashes employed were: (1) tea (Darjeeling first flush:< 0.2 ppm F-), (2) Meridol(R), (3) control (tap water:< 0.2 ppm F-). During the experiment the participants refrained from oral hygiene procedures and rinsed their mouth three times a day after each meal with 20 ml of the respective rinse. After 3 d standardized photographs were taken of the upper canines and premolars and the plaque areas were measured planimetrically. Statistical analysis showed a marked decrease in plaque surface area after rinsing with Meridol, whereas no difference in plaque surface area was observed after mouthrinsing with tea and tap water, respectively.