Fluoride Action Network

More Discussion on Brunelle & Carlos

By Paul Connett, PhD | April 28, 2001

We have received several responses to IFIN #290 on the very meager benefits demonstrated in the largest survey ever conducted on tooth decay in the US (Brunelle and Carlos, 1990).

1) Cory Mermer points out that 0.6 tooth surfaces out of 128 is actually less than 0.5% not just “less than 1%” as we more “modestly” calculated.

2) Dr. Albert Burgstahler points out that Dr. Yiamouyiannis made some criticisms of the Brunelle and Carlos study which have never been refuted, these included pointing out that they did not demonstrate that the O.6 tooth surface difference (out of 128 tooth surfaces) was “statistically significant”. We have printed below the section of Dr. Y’s paper which critiqued the B& C paper. The whole of his paper can be found on our web page. (Also on the website, is the Chemical & Engineering News article from May 8, 1989 which discusses both the Yiamouyiannis and Brunelle/Carlos paper.)

3) Thomas Schmidt points out that employees of the CDC have recently done a “re-analysis” of the Brunelle & Carlos study, in which by looking at fluoridation’s “diffusion” effect, they argue that the benefits are a little better than 0.6 tooth surfaces.

We have printed these three responses below. Meanwhile, we again stress that with all its limitations the Brunelle and Carlos study is the best evidence the pro-fluoridation agencies in this country have for demonstrating a benefit for children’s teeth living in fluoridated communities. It amounts to an incredibly meager 0.6 surfaces out of 128 tooth surfaces. Even if it is assumed that this 0.6 of a tooth surface is statistically significant, again we ask what risks would any one in their right mind take in an attempt to secure such a miniscule benefit?

Paul Connett.

1) From Cory Mermer.

Great response by Mike. However, 0.6 is actually less than 0.5% of 128, which is even less than the 1% you and Mike quote.

Has anyone ever tried to contact Brunelle or Carlos about their study data and conclusion?


2) From Professor Albert Burgstahler.

Dear Paul and Mike,

In his 1990 paper in Fluoride John Y drew attention to some serious errors in the Brunelle-Carlos work that have NEVER BEEN CORRECTED. I urge you to consult that full paper plus what he had in the 1993 edition of his Fluoride the Aging Factor. Some of this material would be worth adding, I think. The points you make are good ones, but the claims B&C make do not really show that water fluoridation accounts even for the small differences they claim.

All the best,

Here is the addendum to Dr. Yiamouyiannis’s 1990 paper in Fluoride. The whole apper can be found on our web page at http://www.fluoridealert.org/DMFTs.htm


“Another recent study by Brunelle and Carlos (31), which also uses the same database that we used, reports a 17% lower DMFS rate in the F areas. This study has a number of major deficiencies which render the study of little or no value.

1. It contains extremely serious errors. For example, by a cursory inspection, we found two values that are off by 100% or more. In their Table 9, the DMFS figure for lifelong F exposure residents of Region VII should be about 3, not 1.46 as reported. From their Table 3, the percent of 5-year-olds who have caries is 1.0%, not the 2.7% that can be calculated from the Table (100%-97.3%). When I pointed out this error to Dr. Carlos, he admitted that only 19 out of the 1851 5-year-olds had caries: 19/1851 = 1%, but refused to make the correction (32).

2. It fails to report the tooth decay rates for each of the 84 geographical areas surveyed. This covers up the fact that there is no difference in the tooth decay rates of the fluoridated and nonfluoridated areas surveyed. The Brunelle/Carlos study even fails to list the area studied. As a result, they produce misleading illustrations; for example, their Figure 3 implies that Arizona and New Mexico have the lowest tooth decay rates, when, in fact, not a single area was surveyed in either of the two states.

3. It fails to control for geographical differences in tooth decay rates by indiscriminately and disproportionately bunching children from all parts of the country into 2 groups, F and NF.

4. It fails to do the statistical analysis (or even provide the data, i.e. the standard deviation and sample number) necessary to determine whether the values found for F and NF areas are significantly different. Our calculations show that even if their data were accurate, the 17.7% figure does not reflect a statistically significant difference between the F and NF groups.

5. It fails to report the data for approximately 23,000 schoolchildren who were not life-time residents of either the F or NF areas (the PF group). If fluoridation reduced tooth decay, the DMFS rate of the PF group should have been greater than that of the F group and less than that of the NF group. Our data indicate that the PF group would have had a DMFS rate higher (although not significantly higher) than either the F or NF groups.

6. It fails to report the data for the percentages of decay-free children in F and NF areas. Our data indicate that had these calculations been done by Brunelle and Carlos, the results may have actually indicated better (although not significantly better) dental health in the NF areas.

Brunelle and Carlos, as well as their employer, the NIDR, have recently come under attack for presenting erroneous data and designing poor experiments which promoted the fluoride mouthrinse program (33). The apparent poor quality of their research regarding the 1986-87 survey (30, 31) is not an isolated case.”


30. Brunelle, J.A.: Caries Attack in the Primary Dentition of U.S. Children. J. Dent. Res., 69(Special Issue):180 [Abstr. No. 575], 1990.
31. Brunelle, J.A. and Carlos, J.P.: Recent Trends in Dental Caries in U.S. Children and the Effect of Water Fluoridation. J. Dent. Res., 69(Special Issue):723-728, 1990.
32. Carlos, J.P.: Personal communication, 1989.
33. Disney, J.A., Bohannan, H.M., Klein, S.P., and Bell, R..M.: A Case Study in Contesting the Conventional Wisdom: School Based Mouthrinse Programs in the USA. Community Dent. Oral Epidemiol., 18:46-56, 1990.

3) From Thomas Scmidt.

Paul –

(1) As CDC has apparently become sensitive to the FACT that 18% is only 0.6 tooth surfaces (and 25% adjusted for supplements and topical treatments is still less than one tooth surface out of 128 total) they have just finished figuring out what the “diffusion effect” was — (see abstract below).

As many times as I read it however, I cannot make heads-or-tails out of it (viz., the above abstract)

(2) It is obviously in preparation for the analysis of the next national survey (of course corrected for about 15 different variables including the “diffusion effect”, the phases-of-the-moon and whatever other variables which may be necessary to prove that Dean was correct)

(3) Even more telling than the fractions of a tooth surface is the dose-response data from the same exact data base (ref. Heller et al, 1997 as tabulated by Locker 1999) which I regressed to the best non-linear fit and then graphed with the origin at 0.3-ppm (viz., what we already have naturally occurring in San Diego). It was in the March issue of our Town Council Newsletter — and I e-mailed a copy to Michael and Hardy.

(4) I spent Sunday at the Earth Day “booth” with Dale Phillip, Jeff Green, and Betty and David Kennedy collecting petition signitures for AB-1565 and the congressional investigation. A memorable exchange was with someone who told me “I’m from Europe and we don’t use that stuff; you Americans are crazy”.


Community Dentistry & Oral Epidemiology 2001 Apr;29(2):120-9

Quantifying the diffused benefit from water fluoridation in the United States.

Griffin SO, Gooch BF, Lockwood SA, Tomar SL.
Division of Oral Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, USA. sig1@cdc.gov

OBJECTIVE: To estimate the total contribution of water fluoridation to caries reduction by including the benefit from the diffusion of fluoride from fluoridated communities to surrounding nonfluoridated communities via the export of bottled beverages and processed foods. METHODS: We analyzed data from the 1986-87 NIDR Children’s Survey for 18,507 school children aged 6-17 years who had at least one permanent tooth and for whom a complete fluoride exposure history could be created. To measure water fluoridation exposure, we generated continuous and categorical exposure variables. Years of fluoridation exposure (YFE-continuous) measured the number of years the child lived at residences receiving fluoridated water. Lifetime fluoridation exposure (LFE-categorical) was high if the child lived at residences receiving fluoridated water more than 50% of his life and low, otherwise. We summed the proportion of state population receiving fluoridated water times the number of years the child had lived in each state and then divided this value by the child’s age to measure diffusion exposure (DE). We grouped DE into three levels: low (DE<=0.25), medium (0.25<DE<0.55), and high (DE>=0.55). For each level of DE, we compared the age-adjusted mean DMFS for high and low LFE. In addition we used linear regression to measure the association between DMFS and YFE while controlling for DE, age, exposures to other fluoride sources, and sociodemographic variables. Reported results are significant at P<0.05. RESULTS: Comparison of mean DMFS scores found that the direct benefit of water fluoridation (DMFS(LFE=low) – DMFS(LFE=high)) was 1.44 surfaces among low DE children and 0 among high DE children. The diffused benefit (DMFS(LFE=low, DE=low) – DMFS(LFE=low, DE=high)) was 1.23 surfaces. The regression results were similar and indicated that the direct benefit would be 1.44 fewer DMFS for low DE children and the indirect benefit would be 1.09 fewer DMFS for high DE children. CONCLUSION: Failure to account for the diffusion effect may result in an underestimation of the total benefit of water fluoridation, especially in high diffusion exposure regions.

PMID: 11300171 [PubMed – in process]

Paul Connett’s comment:

The problem the authors have when trying to cite a “diffusion effect” from the “export of bottled beverages and processed foods” to establish an extra hidden benefit from fluoridated waters, is the well documented European experience. There, according to WHO figures (http://www.fluoridealert.org/govt-statements.htm) the rates of dental decay are equal to or better than the US, yet a) the vast majority of European countries are not fluoridated and b) their children are rarely drinking “imported beverages or processed food” which is made with fluoridated water – unless they are drinking Guiness brewed in Dublin (see IFIN # 284)! Hovever, even if this belated “re-analysis”of the data is taken at face value, the maximum benefits that the authors can ascribe to fluoridation is 1.44 surfaces out of 128 tooth surfaces in a child’s mouth. This is a saving of 1.125% . Our question still stands. How much risk would a rational person take to secure such a meager benefit?