Sunday, December 11, 2005

CDC Fluoridation Recommendations Part 1

On August 17, 2001, the U.S. Centers for Disease Control released new fluoride recommendations. See

This is a fictional conversation between the dentists who wrote the new report (CDC) and an average American (ME). All quotes are from the CDC report exactly as written.
CDC: “In the earliest days of fluoride research, investigators hypothesized that fluoride affects enamel and inhibits dental caries (cavities) only when incorporated into developing dental enamel...”

ME: Hey, we all make mistakes doc.

CDC: “Fluoride works primarily after teeth have erupted…”

ME: Oh, I see. But what does swallowed fluoride do?

CDC: “Fluoride ingested during tooth development can also result in a range of visually detectable changes in enamel opacity... because of hypomineralization.”

ME: What happens?

CDC: “...chalklike, lacy markings across a tooth's enamel surface... In the moderate form, >50% of the enamel surface is opaque white. The rare, severe form manifests as pitted and brittle enamel. After eruption, teeth with moderate or severe fluorosis might develop areas of brown stain. In the severe form, the compromised enamel might break away, resulting in excessive wear of the teeth.

ME: So how does fluoride reduce tooth decay?

CDC: “Fluoride concentrated in plaque and saliva inhibits the demineralization of sound enamel and enhances the remineralization”

ME: But doc, you make me brush off the plaque twice a day. Then your torturer hygienist digs out what I missed twice a year.

CDC: “...fluoride is released from dental plaque in response to lowered pH at the tooth-plaque interface.”

ME: Hello, are you listening? In fact, you or your hygienist brush my off my plaque during my semi-annual cleanings with that gritty fluoride paste.

CDC: “Fluoride-containing paste is routinely used during dental prophylaxis (i.e., cleaning). The abrasive paste, which contains 4,000--20,000 ppm fluoride, might restore the concentration of fluoride in the surface layer of enamel removed by polishing...”

ME: Oh.

CDC: “Fluoride paste is not accepted by FDA or ADA as an efficacious way to prevent dental caries.”

ME: Now you are scaring me, doc. Well, what about the fluoridated toothpaste I use every day?

CDC: “Few studies evaluating the effectiveness of fluoride toothpaste, gel, rinse, and varnish among adult populations are available.”

ME: Man, oh, man!

CDC: “Saliva is a major carrier of topical fluoride”

ME: Oh, I see

CDC: “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.

ME: So the fluoride in saliva is killing Mr. germs!

CDC: “This concentration of fluoride is not likely to affect cariogenic activity”

ME: Hey Abbot. Who’s on first.

CDC: “In laboratory studies, when a low concentration of fluoride is constantly present, one type of cariogenic bacteria, Streptococcus mutans, produces less acid”

ME: Oh, so fluoride kills the Streptococcus mutans that causes tooth decay?

CDC: “Whether this reduced acid production reduces the cariogenicity of these bacteria in humans is unclear”

ME: Is this report supposed to be a comedy?

ME: OK, so fluoride doesn’t incorporate into developing teeth to prevent tooth decay; but does concentrate in the plaque on the outside of my teeth but I brush it off. Fluoride’s in my saliva but at doses not high enough to reduce tooth decay. So fluoride must get into my teeth somehow to prevent cavities.

CDC: “The prevalence of dental caries in a population is not inversely related to the concentration of fluoride in enamel, and a higher concentration of enamel fluoride is not necessarily more efficacious in preventing dental caries.”

ME: Oy! So what’s good about fluoridation?

CDC: "Today, all U.S. residents are exposed to fluoride to some degree, and widespread use of fluoride has been a major factor in the decline in the prevalence and severity of dental caries in the United States and other economically developed countries.”

ME: What’s your reference for that?

CDC: “Reference 1) Bratthall D, Hänsel Petersson G, Sundberg H. Reasons for the caries decline: what do the experts believe? Eur J Oral Sci 1996;104:416--22.”

ME: BELIEVE? But doc remember what happened when you believed ingested fluoride incorporated into developing enamel to reduce tooth decay.? Can’t you do any better. What happened to those early studies with natural fluoride that gave birth to fluoridation?

CDC: “... the limitations of these studies make summarizing the quality of evidence on community water fluoridation as Grade I inappropriate.”

ME: So they just don’t make the grade, huh. That’s a shame. Well, you’ve been adding un-natural fluoride to water supplies for over 50 years. You said you had mounds of studies proving its safety and efficacy. What about those?

CDC: “The quality of evidence from studies on the effectiveness of adjusting fluoride concentration in community water to optimal levels is Grade II-1.”

ME: They don’t make top grade either. Bummer! This is upsetting you. Let’s change the subject. So you want bottled water labels to show fluoride content?

CDC: “Producers of bottled water should label the fluoride concentration of their products.”

ME: This sounds reasonable.

CDC: “In the United States, water and processed beverages (e.g., soft drinks and fruit juices) can provide approximately 75% of a person's fluoride intake.”

ME: Are you asking for the fluoride content labeled on soda and fruit juices?

CDC: (silent on this issue)

ME: What’s so bad about fluoride that it has to be listed on the labels.

CDC: “Fluoride ingested during tooth development can also result in a range of visually detectable changes in enamel opacity… These changes have been broadly termed enamel fluorosis, certain extremes of which are cosmetically objectionable… Severe forms of this condition can occur only when young children ingest excess fluoride, from any source, during critical periods of tooth development.…Concerns regarding the risk for enamel fluorosis are limited to children aged <8>

ME: So how much is too much?

CDC: “Intake that maximally reduces occurrence of dental caries without causing unwanted side effects, including moderate enamel fluorosis.”

ME: I would prefer you tell me the amount that would guarantee against any fluorosis, even mild, but give me what you have.

CDC: From Table 2 - Adequate intake of fluoride for:

· a baby 0-6 months old or 16 pounds is 0.01 milligrams day (mg/day)
· a child 6-12 months or 20 pounds is 0.5 mg/day
· a child 1-3 years or 29 pounds is 0.7
· a child 4-8 years or 48 pounds is 1.1 mg/day

ME: So babies are safe if they drink these amounts even though most of them don’t have teeth to get any topical benefits

CDC: “In a survey of four U.S. cities with different fluoride concentrations in the drinking water (range: 0.37--1.04 ppm), ... infants aged 6 months ingested 0.21--0.54 mg fluoride per day”
ME: Oh my goodness. That’s too high. They may get fluorosis. What should we do?

...Continued in Part II

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