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 applicability of fingernail lead and cadmium levels as subchronic exposure biomarkers for preschool children.

Preschool children are exposed daily to metals in their homes and at daycare centers (DCC). Metal exposure and health effects are associated even at low levels, and children comprise a group of public health concern. Nail metals have been studied for exposure biomonitoring and compared to other biological media. The aim of this study was to explore the applicability of preschool fingernail lead and cadmium as subchronic exposure biomarkers. Nail lead and cadmium levels (NLL and NCL) of 602 preschool children (age: 1-4 years) who attended 21 DCC in São Paulo, Brazil, in 2013 were analyzed. Results were compared against blood lead and cadmium levels (BLL and BCL) found in a previous study. Inductively coupled plasma mass spectrometry (ICP-MS) analyses were performed for both samples. DCC and metal contaminated sites (MCS) were georeferencing. Logistic regression tests were applied to verify associations between nail metal levels and risk factors (sex, age, maternal education, secondary smoking, DCC geographic district, vehicle flow density, relative altitude and distance between DCC and nearest MCS) (p < 0.05). BLL was stratified by exposure level (low: <5 µg.dL-1; high: >13.9 µg.dL-1; medium: ≥5 µg.dL-1 and ≤13.9 µg.dL-1) and also tested the associations in order to verify if nail lead levels are affected by exposure intensity defined by blood metals concentrations. Radius distance and relative altitude of DCC to nearest MCS were associated with high NLL and NCL. Abnormal appearance of nails was associated with high NLL and low NCL. Lead and cadmium exposure magnitude had no significant impact on NLL. NLL should only be used for initial screening, and when financial resources are scarce, especially in areas located near contaminated sites. Preschool children were co-exposed to both lead and cadmium, reinforcing the need for broader studies evaluating exposure to environmental pollutants for more than one chemical element.

Low-fluoride acidic dentifrice: a randomized clinical trial in a fluoridated area.

BACKGROUND: Low-fluoride dentifrices have been suggested as alternatives to reduce dental fluorosis risk, but there is no consensus regarding their clinical effectiveness, which has been suggested to be increased when their pH is acidic. AIMS: This single-blind randomized clinical trial evaluated the caries increment during the use of a low-fluoride acidic liquid dentifrice. METHODS: Four-year-old schoolchildren (n = 1,402) living in a fluoridated area (0.6-0.8 ppm F) were randomly allocated to 4 groups differing according to the type of dentifrice used over a 20-month period. Group 1 (n = 345): liquid dentifrice, 1,100 ppm F, pH 4.5. Group 2 (n = 343): liquid dentifrice, 1,100 ppm F, pH 7.0. Group 3 (n = 354): liquid dentifrice, 550 ppm F, pH 4.5. Group 4 (n = 360): toothpaste, 1,100 ppm F, pH 7.0. At baseline and after 20 months, clinical examinations were conducted (dmfs index) and caries increment was calculated. Data were analysed by GLM procedure using classrooms (cluster) as unit of analysis (p < 0.05). RESULTS: The mean ± SD (95% CI) net increments found were as follows. Group 1: 2.06 ± 2.38 (1.8-2.3); group 2: 2.08 ± 2.87 (1.7-2.4); group 3: 2.05 ± 2.79 (1.7-2.4), and group 4: 2.08 ± 2.34 (1.8-2.4). No significant differences were detected among the groups. CONCLUSION: In a population with high caries risk living in a fluoridated area, as the selected sample, and according to the present protocol, the low-fluoride acidic liquid dentifrice seems to lead to similar caries progression rates as conventional 1,100 ppm F toothpaste.

Low-fluoride dentifrices with reduced pH: fluoride concentration in whole saliva and bioavailability.

This double-blind study assessed the fluoride (F) concentration in whole saliva and F bioavailability after the use of low-F dentifrices with reduced pH. Whole saliva was collected from 10 volunteers after brushing with: experimental dentifrices (pH 5.5) 275, 550 and 1,100 ppm F; commercial 500 ppm F, pH 6.9 and a 'gold standard' 1,100 ppm F, pH 6.5. To analyze F bioavailability, 9 volunteers ingested weights of four dentifrices equivalent to 2 mg F: 1,500 ppm F/MFP/CaCO3, pH 9.5; 1,100 ppm F/NaF/silica, pH 5.5; 1,100 ppm F/NaF/silica, pH 7.0 and 1,100 ppm F/NaF/silica, pH 6.5 ('gold standard'). Ductal saliva and urine were collected. F was analyzed by electrode. Data were tested using ANOVA and Tukey's post hoc test (p < 0.05). The 550 ppm F/pH 5.5 dentifrice was similar to the 'gold standard' in its effect on whole saliva F concentration. The area under the curve of ductal saliva F concentration x time and urinary F excretion rates did not differ among the dentifrices. The results show that acidic low-F dentifrices are effective in increasing salivary F concentration and pH reduction does not seem to affect their F bioavailability.

Effectiveness of a chlorhexidine dentifrice in orthodontic patients: a randomized-controlled trial.

This blind and randomized-controlled trial analysed chlorhexidine dentifrices in relation to dental plaque, gingivitis, bleeding, calculus and enamel extrinsic staining development. Volunteers in fixed orthodontic therapy used the following dentifrices: 1100 ppmF, NaF (group A, n=27); experimental, 1100 ppmF, NaF and chlorhexidine 0.95% (group B, n=28); and experimental, chlorhexidine 0.95% (group C, n=28). At baseline, after 6, 12 and 24 weeks, clinical examinations were carried out. The gingivitis, bleeding and plaque data were tested by anova and Tukey's post hoc tests. Stain and calculus data were analysed by Kruskal-Wallis and Dunn's post hoc tests (p<0.05). Plaque, gingivitis and bleeding scores improved in all three groups, but up to the 6 and 12 weeks examination the products containing chlorhexidine were statistically better. The chlorhexidine dentifrices significantly increased the mean of the stain index, although most of the patients did not notice the stains. The calculus index was not significantly modified. In summary, this study suggests that the use of dentifrices containing chlorhexidine seems to be effective for the treatment of gingivitis in orthodontic patients, although the intense motivating contact that the volunteers had with the researchers may have also played a role.

Trends in dental caries prevalence in 12-year-old schoolchildren between 1976 and 2001 in Bauru, Brazil.

OBJECTIVE: To evaluate the trends in dental caries prevalence in 12-year-old schoolchildren between 1976 and 2001 in Bauru, Brazil. Study design. An epidemiological survey was performed by trained, calibrated examiners by the same research group in 1976, 1984, 1990, 1995 and 2001, using the decayed, missing and filled teeth (DMFT) index. METHODS: Urban elementary schools were chosen because they provide a fair representation of the city's population in terms of socio-economic status. The study included 261, 321, 253, 377 and 211 subjects from the same regions in 1976, 1984, 1990, 1995 and 2001, respectively. The prevalence of caries and the DMFT index were used. RESULTS: A remarkable decrease was seen in the DMFT index at age 12 (84.53%) between 1976 and 2001. The DMFT indices at age 12 were 9.89, 7.01, 3.97, 4.13 and 1.53 in 1976, 1984, 1990, 1995 and 2001, respectively. The percentage of schoolchildren presenting with sound permanent teeth (DMFT = 0) increased from 0.40 to 45.50% between 1976 and 2001. Over the same period, the percentage of schoolchildren with six or more decayed teeth decreased from 86.99% to 5.21%. CONCLUSIONS: The phenomenon of dental caries polarization is already perceptible in Bauru, Brazil. The increase in the number of schoolchildren with sound permanent teeth (DMFT = 0) suggests that the dental health policy in Bauru has had a positive effect in children's dental health, and should therefore be considered for other cities.