Effect of xylitol varnishes on remineralization of artificial enamel caries lesions in situ.

OBJECTIVES: Analyze the effect of varnishes containing xylitol compared to commercial fluoridated varnishes on the remineralization of artificial enamel caries lesions in situ. METHODS: Twenty subjects took part in this crossover, double-blind study performed in four phases of 5days each. Each subject worn palatal appliances containing four predemineralized bovine enamel specimens. Artificial caries lesions were produced by immersion in 30ml of lactic acid buffer containing 3mM CaCl2·2H2O, 3mM KH2PO4, 6µM tetraetil metil diphosphanate (pH 5.0) for 6days. The specimens in each subject were treated once with the following varnishes: 20% xylitol (experimental); Duofluorid™ (6% NaF, 6% CaF2), Duraphat™ (5% NaF, positive control) and placebo (no-F/xylitol, negative control). The varnishes were applied in a thin layer and removed after 6h. Fifteen subjects were able to finish all phases. The enamel alterations were quantified by surface hardness and transversal microradiography. The percentage of surface hardness recovery (%SHR), the integrated mineral loss and lesion depth were statistically analyzed by Friedmann and Dunn's tests test (p<0.05). RESULTS: Enamel surface remineralization was significantly increased by Duraphat™, Duofluorid™ and 20% xylitol formulations. Significant subsurface mineral remineralization could also be seen for the experimental and commercial varnishes, except for Duraphat™, when the parameter "lesion depth" was considered. CONCLUSIONS: 20% xylitol varnish seem to be a promising alternative to increase surface and subsurface remineralization of artificial caries lesions in situ. CLINICAL SIGNIFICANCE: effective vehicles are desirable for caries control. Xylitol varnishes seem to be promising alternatives to increase enamel remineralization in situ, which should be confirmed by clinical studies.

Total fluoride intake and excretion in children up to 4 years of age living in fluoridated and non-fluoridated areas.

Fractional fluoride retention is important during the early years of life when considering the risk of development of dental fluorosis. This study aimed to measure fractional fluoride retention in young children. The objectives were to investigate the relationships between fractional fluoride retention and total daily fluoride intake, age, and body mass index (BMI). Twenty-nine healthy children, up to 4 yr of age, participated; 14 lived in a fluoridated area (0.64 µg ml(-1) of fluoride in drinking water) and 15 lived in a non-fluoridated area (0.04 µg ml(-1) of fluoride in drinking water). The total daily fluoride intake of each child was calculated from the daily dietary fluoride intake and toothpaste ingestion (if fluoride toothpaste was used). Total daily fluoride excretion was measured by collecting voided urine and faeces over a 24-h period, and fractional fluoride retention was calculated by dividing the amount of fluoride retained in the body (total daily fluoride intake minus total daily fluoride excretion) by the total daily fluoride intake. Nine children were excluded from data analysis because of suspected invalid samples. Mean (range) fractional fluoride retention for the remaining 20 children was 0.61 (0.06-0.98). There were no statistically significant correlations between fractional fluoride retention and either age or BMI. However, fractional fluoride retention was correlated with total daily fluoride intake: fractional fluoride retention = 1 - exp (-C × total daily fluoride intake), where C = 28.75 (95% CI = 19.75-37.75). The wide variation in fluoride retention in young children could have important implications when recommendations for fluoride use are being considered.

The effect of different fluoride concentrations and pH of dentifrices on plaque and nail fluoride levels in young children.

To evaluate the influence of dentifrice pH and fluoride (F) concentration on F uptake by plaque and nails, two sets of 5- to 6-year-old children were randomly allocated into four groups, according to the type of dentifrice they had been using for 1 year: (1) experimental liquid dentifrice (ELD), 1,100 ppm F, pH 7.0; (2) ELD, 1,100 ppm F, pH 4.5; (3) ELD, 550 ppm F, pH 4.5, and (4) commercial toothpaste, 1,100 ppm F, pH 7.0. In one set of children, nails were clipped. In the second, plaque samples were collected 1 h after the last use of dentifrice. F concentration in plaque and nails was analyzed. Plaque F concentration was significantly lower in group 4 than in groups 1-3. Nail F concentration was significantly higher in group 4, and significantly lower in group 3, than in group 1 or 2. Plaque F uptake was influenced significantly by dentifrice consistency and nonsignificantly by pH and F concentration. Reduction of dentifrice pH did not affect nail F concentration.