Another Q-
We don't have fluoridated water, and we haven't for four years. We use floridated toothpaste, so is that a big deal in your opinion? Our hygienist wants us to buy fluoridated water for kids, but it seems unnecessary to drink it, right?
Although fluoride is great at cleaning teeth, it was never meant to be swallowed - which is why the toothpaste manufacturers direct you to call a poison control center should a small child accidentally swallow any (really - look at the label). I actually have a filter on my sink that takes fluoride out. Save money; don't buy the fluoridated water.
Fluoride doesn't really clean teeth. It is absorbed by the enamel, which strengthens it and protects it against decay.
Fluoride is dangerous to consume *in large amounts in a single dose*, or *in large amounts continuously*. There are many ions or molecules that are dangerous this way. If a small child somehow ate a cup of salt, that would also be dangerous, but a small consumption of salt every day is important for maintaining blood osmolarity, the function of the nervous system, etc.
The main danger of massive fluoride consumption is that fluoride is up-taken by bone, causing skeletal fluorosis. This is extremely rare in developed countries because the concentrations in drinking water are carefully monitored and truly massive doses of fluoride are necessary to begin to show symptoms.
http://en.wikipedia.org/wiki/Skeletal_fluorosisMunicipal fluoridated drinking water is completely safe for regular consumption. In fact, fluoridated drinking water has been shown in almost every study over the last 60+ years to be an incredibly cheap, safe, and effective public health intervention, joining the likes of iodized salt and enriched flour.
http://www.cdc.gov/fluoridation/safety/systematic.htmhttp://www.cdc.gov/mmwr/preview/mmwrhtml/rr5014a1.htmThe reason your hygienist wants you to supplement the kids' fluoride intake is that fluoride intake during childhood has been shown to have life-long protective effect for the health of teeth.
Some relevant quotes (bolding mine)
"Because frequent exposure to small amounts of fluoride each day will best reduce the risk for dental caries in all age groups, the work group recommends that all persons drink water with an optimal fluoride concentration and brush their teeth twice daily with fluoride toothpaste. For persons at high risk for dental caries, additional fluoride measures might be needed.
Measured use of fluoride modalities is particularly appropriate during the time of anterior tooth enamel development (i.e., age <6 years). "
"Fluoride works to control early dental caries in several ways. Fluoride concentrated in plaque and saliva inhibits the demineralization of sound enamel and enhances the remineralization (i.e., recovery) of demineralized enamel (12,13). As cariogenic bacteria metabolize carbohydrates and produce acid, fluoride is released from dental plaque in response to lowered pH at the tooth-plaque interface (14). The released fluoride and the fluoride present in saliva are then taken up, along with calcium and phosphate, by de-mineralized enamel to establish an improved enamel crystal structure. This improved structure is more acid resistant and contains more fluoride and less carbonate (12,15--19) (Figure 1). Fluoride is more readily taken up by demineralized enamel than by sound enamel (20).
Cycles of demineralization and remineralization continue throughout the lifetime of the tooth. [eg, lifelong]
Fluoride also inhibits dental caries by affecting the activity of cariogenic bacteria. As fluoride concentrates in dental plaque, it inhibits the process by which cariogenic bacteria metabolize carbohydrates to produce acid and affects bacterial production of adhesive polysaccharides (21). In laboratory studies, when a low concentration of fluoride is constantly present, one type of cariogenic bacteria, Streptococcus mutans, produces less acid (22--25). Whether this reduced acid production reduces the cariogenicity of these bacteria in humans is unclear (26).
Saliva is a major carrier of topical fluoride. The concentration of fluoride in ductal saliva, as it is secreted from salivary glands, is low --- approximately 0.016 parts per million (ppm) in areas where drinking water is fluoridated and 0.006 ppm in nonfluoridated areas (27). This concentration of fluoride is not likely to affect cariogenic activity. However, drinking fluoridated water, brushing with fluoride toothpaste, or using other fluoride dental products can raise the concentration of fluoride in saliva present in the mouth 100- to 1,000-fold.
The concentration returns to previous levels within 1--2 hours but, during this time, saliva serves as an important source of fluoride for concentration in plaque and for tooth remineralization (28). "
"
Initial studies of community water fluoridation demonstrated that reductions in childhood dental caries attributable to fluoridation were approximately 50%--60% (94--97). More recent estimates are lower --- 18%--40% (98,99). This decrease in attributable benefit is likely caused by the increasing use of fluoride from other sources, with the widespread use of fluoride toothpaste probably the most important. The diffusion or "halo" effect of beverages and food processed in fluoridated areas but consumed in nonfluoridated areas also indirectly spreads some benefit of fluoridated water to nonfluoridated communities. This effect lessens the differences in caries experience among communities (100).
Quantifying the benefits of water fluoridation among adults is more complicated because adults are rarely surveyed, their fluoride histories are potentially more varied, and their tooth loss or restorations might be caused by dental problems other than caries (e.g., trauma or periodontal diseases).
Nevertheless, adults are reported to receive caries-preventive benefits from community water fluoridation (99,101--103). These benefits might be particularly advantageous for adults aged >50 years, many of whom are at increased risk for dental caries. Besides coronal caries, older adults typically experience gingival recession, which results in teeth with exposed root surfaces. Unlike the crowns of teeth, these root surfaces are not covered by enamel and are more susceptible to caries. Because tooth retention among older age groups has increased in recent decades in the United States (39), these groups' risk for caries will increase as the country's population ages. Older adults also frequently require multiple medications for chronic conditions, and many of these medications can reduce salivary output (104). Drinking water containing an optimal concentration of fluoride can mitigate the risk factors for caries among older adults.
Studies have reported that the prevalence of root caries among adults is inversely related to fluoride concentration in the community drinking water (105--107)."
