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SCIENCE SECTION

Ireland 5

A SCIENTIFIC CRITIQUE OF THE FLUORIDATION FORUM REPORT, IRELAND 2002.

5) Inadequacies of the Forum's dental analysis.

5.1 Is fluoridation preventing dental caries?

The results of several Irish studies were summarized on pp. 100-103. As presented, the data appears to show that fluoridation had a very minor benefit in terms of reducing overall DMFT (Decayed, Missing and Filled Teeth) rates. However, there are problems with the data that the authors did not address.

1. How do they explain the drop in dental caries in subjects who were life-long residents in both the non-fluoridated and fluoridated areas? While this phenomenon is acknowledged on p. 102, it is claimed that "The reduction, however, was greatest in the fluoridation communities", resulting in a 23% overall difference in 12 year olds, or a net difference of 0.7 DMFT.

2. The authors did not correct for a delay in tooth eruption from fluoride ingestion (See Kunzel et al, 1976; Krook et al, 1983; Virtanen et al, 1994; Campagna et al, 1995; Limeback, 2002.) This was pointed out to Dr. O'Mullane when external input was sought but this seems to have been ignored altogether. If one uses the UK data as reported by Diesendorf in 1986, a simple calculation will indicate that the 0.7 DMFT "benefit" can be explained by a delay in tooth eruption.

3. The "benefits" from water fluoridation in adults, when delayed tooth eruption no longer has an effect, are minor. The use of DMFT as a tool for measuring dental decay is flawed in that it is affected by tooth loss from periodontal disease. No where in the report was this mentioned. Apart from one study (ref. 75), which was not a case-control study , the "benefits" from fluoridation for adults is minor. Many factors affect caries risk, such as mature onset diabetes (Narhi et al, 1996) and these must be taken into account when comparing populations.

4. A carefully conducted, randomized, prospective clinical trial on water fluoridation has never been conducted, not in Ireland, nor anywhere else in the world. This is the kind of clinical evidence that is required to approve drugs for human use. Why should placing a drug in the water be any different?

In the US, the net benefit from fluoridation 15 years ago was minor. According to Hunt et al (1989),

"Coronal caries incidence was significantly lower for people who had resided in fluoridated communities for more than 30 years (1.95 vs 1.33 surfaces). Root caries incidence was significantly less among residents for more than 40 years (0.56 vs 1.11 surfaces)."

Today, after many years of fluoridated tooth paste use, one would likely find these differences eroded even further.

Nowhere in the report is there an accounting of how much money has been spent on fluoridation in Ireland. After 30 years of water fluoridation, how many actual tooth surfaces were saved from decay?

It is our contention that, if a delay in tooth eruption is factored in, the number of fillings saved per child is impossible to estimate unless the entire child population receives a dental examination. Even if a net statistically significant difference could be found in adults, it would be so small as to be clinically irrelevant.

5.2 Dental Fluorosis and the critical time of exposure.

According to a statement on p. 128 of the Forum report, "It would appear that the risk of dental fluorosis in the maxillary central incisors is low in the first 15 months of life."

To support this statement only one study is cited, that of Evans and Darwell (1995). While this study has been highly cited for trying to pinpoint the window of susceptibility, recent studies (Ishii and Suckling, 1991; Milsom et al 1996; Ismail et al, 1996; Bardsen and Bjortvatn, 1998; Brothwell and Limeback, 1999 and Fomon et al, 2000) show that exposure right from birth (during the first year) clearly increases the risk for dental fluorosis. Evansâ study may, therefore, be flawed (Burt, personal communication).

According to Bardsen and Bjorvatn:

"The findings indicate that early mineralizing teeth (central incisors and first molars) are highly susceptible to dental fluorosis if exposed to fluoride from the first and - to a lesser extent - also from the 2nd year of life."

According to Milsom et al:

"In light of these findings, it is worth considering the potential of the presence of enamel defects in deciduous molars in children aged 1 to 3 years as a predictor of the future appearance of similar lesions in their permanent incisors."

According to Ismail et al:

"The odds that a child had a maxillary central incisor with fluorosis were 5.69 (95% CI = 1.34, 24.15) times higher if exposure occurred during the first year of life compared with exposure after 1 year of age."

According to Brothwell and Limeback:

"Breast-feeding for 6 months or more may protect children from developing dental fluorosis in the permanent incisors."

According to Ishii and Suckling:

"Two 'at-risk' periods for the production of moderate or severe fluorosis were evident. One started at birth and ended early in tooth development, while the other started later and ended at eruption."

According to Fomon et al:

"We believe the most important measures that should be undertaken are (1) use, when feasible, of water low in fluoride for dilution of infant formulas; (2) adult supervision of toothbrushing by children younger than 5 years of age; and (3) changes in recommendations for administration of fluoride supplements so that such supplements are not given to infants and more stringent criteria are applied for administration to children."

5.3 Dental Fluorosis and Infant feeding.

On p.133 of the Forum report, the authors state that:

"It is recommended that parents continue to reconstitute infant formula with boiled tap water. Many brands of bottled water available in Ireland are not suitable for use in the reconstitution of infant formula due to the presence of salt and other substances which may be harmful to infants and young children."

It is hard to believe that this is a serious statement. Natural water has "salts" that may be harmful to the baby? Where are the studies to back this statement? What about the silicofluorides artificially added to tap water that are concentrated when boiled? The effect on infant development of these chemicals has never been tested. How can these chemicals be recommended as additives to infant formula over natural "salts" contained in bottled water?

On p.134 of the report, the authors state that:

"An increase in the rate of breast feeding in this country would contribute significantly to a reduction of the occurrence of dental fluorosis."

If the Forum panel recognizes this to be true, then why promote dental fluorosis by continuing to recommend the use of infant formula made with boiled tap water which results in infant formula that has 100 times the level of fluoride as human breast milk?

If there is any doubt that infant formula made with fluoridated water increases dental fluorosis, whether at the old 1.0 ppm "optimal" level or the new 0.7 ppm "target" level, one only has to read the literature on the subject. The number of studies that have examined this problem is large. Why were the studies by Pendrys and Katz, 1989; Clark et al, 1994; Pendrys et al, 1994; Van Winkle et al, 1995; Grimaldo et al, 1995; Lewis and Limeback, 1996; Silva and Reynolds, 1996; Villa et al, 1998; Fomon and Ekstrand, 1999; Brothwell and Limeback, 1999; Pendrys, 2000; and Buzalef et al, 2001, ignored and not considered by the members of the fluoridation forum.

One must ask why this task was given to the Food Safety Authority of Ireland (FSAI) instead of being addressed by the Forum panel. Here are some key exerpts from some of these reports.

According to Buzalaf, 2001:

"Hence, to limit fluoride intakes to amounts <0.1 mg/kg/day, it is necessary to avoid use of fluoridated water (around 1 ppm) to dilute powdered infant formulas."

According to Pendrys, 2000:

"Enamel fluorosis in the optimally fluoridated study sample was attributed to early toothbrushing behaviors, inappropriate fluoride supplementation and the use of infant formula in the form of a powdered concentrate."

According to Fomon and Ekstrand, 1999:

"Many fewer infants are exposed to high F intakes from formula plus a supplement (recommended only for communities with water providing less than 0.3 ppm F) than from formula alone in communities with F content of 1 ppm in the drinking water."

According to Brothwell and Limeback, 1999:

"Breast-feeding for 6 months or more may protect children from developing dental fluorosis in the permanent incisors."

According to Villa et al, 1998:

"Subjects in Group I were 20.44 times more likely (95% CI: 5.00-93.48) to develop CMI fluorosis than children who were older than 24 months (Group III) when fluoridation began."

According to Silva and Reynolds, 1996:

"However, prolonged consumption (beyond 12 months of age) of infant formula reconstituted with optimally-fluoridated water could result in excessive amounts of fluoride being ingested during enamel development of the anterior permanent teeth and therefore may be a risk factor for fluorosis of these teeth."

According to Grimaldo et al, 1995:

"91% used infant formula reconstituted with boiled water." "Taking together all these results, three risk factors for human exposure to fluoride in SLP can be identified: ambient temperature, boiled water, and food preparation with boiled water."

According to Clark et al, 1994:

"Logistic regression analyses showed that the use of infant formula and parental educational attainment were significantly associated with the occurrence of dental fluorosis in the range of scores from 2 to 6."

According to Pendrys et al, 1994:

"Logistic regression analyses, which adjusted for confounding variables, revealed that mild-to moderate enamel fluorosis on early forming (Fluorosis Risk Index (FRI) classification I) enamel surfaces was strongly associated with both milk-based (odds ratio (OR) = 3.34, 95% confidence interval (CI) 1.38-8.07) and soy-based (OR = 7.16, 95% CI 1.35-37.89) infant formula use,"

According to Pendrys and Katz, 1989:

"An odds ratio of 1.7 associated with infant formula use was suggestive of an increased risk of enamel fluorosis"

5.5 Conclusion on the Forum's dental analysis:

The report fails to demonstrate that over 30 years of fluoridation in Ireland has actually prevented tooth decay. Nor do the Forum authors attempt to put the Irish dental findings into the larger context of studies conducted elsewhere. For example, they do not mention the largest survey conducted in the US (Brunelle and Carlos, 1990) in which the authors could only find an average difference in tooth decay of 0.6 of one tooth surface out of 128 tooth surfaces for children (aged 5 -17 years) who had lived their whole lives in fluoridated communities compared to non-fluoridated ones. Even this minuscule difference was not shown to be statistically significant by the authors. Nor do they cite the work of Spencer et al (1996) who report an even smaller difference of 0.12 - 0.3 tooth surfaces in Australia. In New Zealand, de Liefde (1998) reports differences in tooth decay as being not clinically significant. Nor do they adequately address the fact that the vast majority of European countries have been able to achieve comparable, or lower, levels of dental decay as in Ireland, without fluoridating their water supplies. Finally, they do not acknowledge that where in recent years fluoridation has been halted in communities in Finland, Cuba, former East Germany and Canada, tooth decay rates have not gone up as predicted by promoters of fluoridation, but have actually gone down (Maupome et al, 2001; Kunzel and Fischer,1997,2000; Kunzel et al, 2000; and Seppa et al, 2000).

Further, the Forum authors do not provide convincing evidence that fluoridated water, even at the new target level of 0.7 ppm, does not, and will not, cause dental fluorosis when used to make up infant formula.


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