Fluoride

The purpose of this study was to assess exposure to drinking water fluoride and evaluate the risk of dental fluorosis among the Estonian population. The study covered all 15 counties in Estonia and 93.7% of population that has access to public water supplies. In Estonia groundwater is the main source for public water supply systems in most towns and rural settlements. The content of natural fluoride in water ranges from 0.01 to 7.20 mg/L. The exposure to different fluoride levels was assessed by linking data from previous studies on drinking water quality with databases of the Health Protection Inspectorate on water suppliers and the number of water consumers in water supply systems. Exposure assessment showed that 4% of the study population had excessive exposure to fluoride, mainly in small public water supplies in western and central Estonia, where the Silurian-Ordovician aquifer system is the only source of drinking water. There is a strong correlation between natural fluoride levels and the prevalence of dental fluorosis. Risk of dental fluorosis was calculated to different fluoride exposure levels over 1.5 mg/L.

Two contradictory hypotheses on the role of dietary carbohydrates in health and disease shape how dental-systemic associations are regarded. On one side, Cleave and Yudkin postulated that excessive dietary fermentable carbohydrate intake led-in the absence of dental interventions such as fluorides-first to dental diseases and then to systemic diseases. Under this hypothesis, dental and systemic diseases shared-as a common cause-a diet of excess fermentable carbohydrates. Dental diseases were regarded as an alarm bell for future systemic diseases, and restricting carbohydrate intake prevented both dental and systemic diseases. On the opposite side, Keys postulated the lipid hypothesis: that excessive dietary lipid intake caused systemic diseases. Keys advocated a diet high in fermentable carbohydrate for the benefit of general health, and dental diseases became regarded as local dietary side effects. Because general health takes precedence over dental health when it comes to dietary recommendations, dental diseases became viewed as local infections; interventions such as fluorides, sealants, oral hygiene, antimicrobials, and dental fillings became synonymous with maintaining dental health, and carbohydrates were no longer considered as a common cause for dental-systemic diseases. These opposing dietary hypotheses have increasingly been put to the test in clinical trials. The emerging trial results favor Cleave-Yudkin’s hypothesis and may affect preventive approaches for dental and systemic diseases.

Since silicofluorides aren’t used in other coun-tries and are associated with a significant increase in the fre-quency of seven different diseases, stopping their use should be combined with screening and treating children for high body burdens of other toxins. As this suggestion indicates, Americans urgently need to focus on national health policy, can improve health at virtually no cost by ending silicofluoride use, and – as soon as possible – consider ways to increase public financing of medical care.

OBJECTIVES:
The “optimal” intake of fluoride has been widely accepted for decades as between 0.05 and 0.07 mg fluoride per kilogram of body weight (mg F/kg bw) but is based on limited scientific evidence. The purpose of this paper is to present longitudinal fluoride intake data for children free of dental fluorosis in the early-erupting permanent dentition and free of dental caries in both the primary and early-erupting permanent teeth as an estimate of optimal fluoride intake.

METHODS:
Data on fluoride ingestion were obtained from parents of 602 Iowa Fluoride Study children through periodic questionnaires at the ages of 6 weeks; 3, 6, 9, 12, 16, 20, 24, 28, 32, and 36 months; and then at 6-month intervals thereafter. Estimates of total fluoride intake at each time point were made by summing amounts from water, dentifrice, and supplements, as well as other foods and beverages made with, or containing, water. Caries data were obtained from examinations of children at ages 5 and 9 years, whereas fluorosis data were obtained from examinations of children only at age 9 years.

RESULTS:
The estimated mean daily fluoride intake for those children with no caries history and no fluorosis at age 9 years was at, or below, 0.05 mg F/kg bw for nearly all time points through the first 48 months of life, and this level declined thereafter. Children with caries had generally slightly less intakes, whereas those with fluorosis generally had slightly higher intakes.

CONCLUSIONS:
Given the overlap among caries/fluorosis groups in mean fluoride intake and extreme variability in individual fluoride intakes, firmly recommending an “optimal” fluoride intake is problematic.

MAIN RESULTS:
Seventy-four studies were included. For the 70 that contributed data for meta-analysis (involving 42,300 children) the D(M)FS pooled PF was 24% (95% confidence interval (CI), 21 to 28%; p<0.0001). This means that 1.6 children need to brush with a fluoride toothpaste (rather than a non-fluoride toothpaste) over three years to prevent one D(M)FS in populations with caries increment of 2.6 D(M)FS per year. In populations with caries increment of 1.1 D(M)FS per year, 3.7 children will need to use a fluoride toothpaste for three years to avoid one D(M)FS. There was clear heterogeneity, confirmed statistically (p<0.0001). The effect of fluoride toothpaste increased with higher baseline levels of D(M)FS, higher fluoride concentration, higher frequency of use, and supervised brushing, but was not influenced by exposure to water fluoridation. There is little information concerning the deciduous dentition or adverse effects (fluorosis).

REVIEWER’S CONCLUSIONS:
Supported by more than half a century of research, the benefits of fluoride toothpastes are firmly established. Taken together, the trials are of relatively high quality, and provide clear evidence that fluoride toothpastes are efficacious in preventing caries.

“Objectives: There have been few reports regarding variations of fluoride intake by fluid consumption patterns. The purpose of this study was to estimate fluoride intake among children in the United States based on their fluid consumption patterns.

Methods: Fluid intakes of children aged 1-10 years from plain water, beverages, and water from foods were assessed in a 24-hour recall diet survey as a part of the third National Health and Nutritional Examination Survey (NHANES III, 1988-1994). The amount of fluoride ingested from fluids in NHANES III was estimated from several assumptions about the concentration of fluoride in drinking water and beverages. Logistic regression analysis was conducted using SAS® and SUDAAN®.

Results: Children at the 75th percentile or higher of F intake from fluids (not including water used in cooking) ingested 0.05 mg F/kg/day or more, and children at the 90th percentile or higher ingested 0.07 mg F/kg/day or more. This finding held across all age groups. There was substantial variation in the estimated amount of fluoride ingestion depending on the children’s fluid consumption patterns as well as age, gender, and race/ethnicity. African-American children ingested significantly more fluoride than White children in bivariate analysis. This association remained significant after accounting for fluid consumption pattern and other confounding factors in the model.

Conclusion: Our results raise concerns that some children are ingesting significantly more fluoride than others depending on sociodemographic factors and fluid consumption patterns. Additional research is warranted to investigate the variation in the amounts of fluoride ingestion by these factors and its impact on fluorosis prevalence in different population groups. “

“Intake of excess amounts of fluoride during tooth development cause enamel fluorosis, a developmental disturbance that makes enamel more porous. In mild fluorosis, there are white opaque striations across the enamel surface, whereas in more severe cases, the porous regions increase in size, with enamel pitting, and secondary discoloration of the enamel surface. The effects of fluoride on enamel formation suggest that fluoride affects the enamel-forming cells, the ameloblasts. Studies investigating the effects of fluoride on ameloblasts and the mechanisms of fluorosis are based on in vitro cultures as well as animal models. The use of these model systems requires a biologically relevant fluoride dose, and must be carefully interpreted in relation to human tooth formation. Based on these studies, we propose that fluoride can directly affect the ameloblasts, particularly at high fluoride levels, while at lower fluoride levels, the ameloblasts may respond to local effects of fluoride on the mineralizing matrix. A new working model is presented, focused on the assumption that fluoride increases the rate of mineral formation, resulting in a greater release of protons into the forming enamel matrix.”

OBJECTIVES:
The biological effects of resin-modified glass-ionomer cements as used in clinical dentistry are described, and the literature reviewed on this topic.

METHODS:
Information on resin-modified glass-ionomers and on 2-hydroxyethyl methacrylate (HEMA), the most damaging substance released by these materials, has been collected from over 50 published papers. These were mainly identified through Scopus.

RESULTS:
HEMA is known to be released from these materials and has a variety of damaging biological properties, ranging from pulpal inflammation to allergic contact dermatitis. These are therefore potential hazards from resin-modified glass-ionomers. However, clinical results with these materials that have been reported to date are generally positive.

CONCLUSIONS/SIGNIFICANCE:
Resin-modified glass-ionomers cannot be considered biocompatible to nearly the same extent as conventional glass-ionomers. Care needs to be taken with regard to their use in dentistry and, in particular, dental personnel may be at risk from adverse effects such as contact dermatitis and other immunological responses.

PURPOSE:
The aim of this in vivo pilot study was to determine the concentration of fluoride retained intra-orally in saliva after flossing with dental floss impregnated with stannous fluoride (SnF(2)).

METHODS:
Participants flossed their teeth ad libitum with 2 premeasured lengths of fluoridated dental floss. Expectorated saliva samples were collected in vials before flossing (PF), immediately postflossing(IPF), at 30 minutes (30), and 1 hour (60) after flossing for analysis with a fluoride-specific electrode and an Orion millivoltmeter. Postflossing samples were compared to the preflossing samples using ANOVA and Tukey’s HSD.

RESULTS:
Differences between the PF and IPF group means were found to be statistically significant at p<0.01. No other significant differences were found between or among any of the groups. Salivary fluoride levels at 60 minutes (60) were similar to those prior to flossing (PF).

CONCLUSIONS:
It can be concluded that fluoride can be released from flossing with the tested SnF(2)-impregnated dental floss elevating salivary fluoride levels for at least 30 minutes. Use of this fluoride-containing dental floss offers an option for delivery of fluoride to individuals at risk for dental caries.

Water fluoridation has been identified by CDC as one of 10 great public health achievements of the 20th century. The decline in the prevalence and severity of dental caries (tooth decay) in the United States during the past 60 years has been attributed largely to the increased use of fluoride. Community water fluoridation is an equitable and cost-effective method for delivering fluoride to the community. A Healthy People 2010 objective is to increase to 75% the proportion of the U.S. population served by community water systems who receive optimally fluoridated water. To update and revise previous reports on fluoridation in the United States and describe progress toward the Healthy People 2010 objective, CDC analyzed fluoridation data for the period 1992-2006 from the 50 states and District of Columbia (DC). The results indicated that the percentage of the U.S. population served by community water systems who received optimally fluoridated water increased from 62.1% in 1992, to 65.0% in 2000, and 69.2% in 2006, and those percentages varied substantially by state. Public health officials and policymakers in states with lower percentages of residents receiving optimal water fluoridation should consider increasing their efforts to promote fluoridation of community water systems to prevent dental caries.