No permanent benefit from fluoridation
Consumption of nonpublic water: implications for children’s caries experience
– Jason M. Armfield and A. John Spencer, Community Dentistry And Oral Epidemiology Volume 32 Issue 4 Page 283 – August 2004
The study was conducted due to concerns that the consumption of unfluoridated bottled and tank water may put children at increased risk of developing caries. The objective was to investigate the relationship between nonpublic water consumption (either from bottles or rainwater tanks) and socioeconomic status (SES) and both deciduous and permanent caries experience. (deciduous teeth are “milk” teeth)
Result: no significant benefit to permanent teeth from fluoridation.
In comparison with children drinking mineral-deficient tank (rain) water, which was never addressed as a possible (and more likely) cause of the difference than fluoride, there was a clinically minimal ( a fraction of a dmfs) though statistically significant (57.1%) but clinically minimal benefit, for milk teeth (children aged 4-9), but only with 100% lifetime exposure to fluoridation not have been the cause of the difference anyway. The study did not aim to address adverse health effects from fluoridation.
More significantly, the study showed up to 137.9% difference in decay rates based on socio-economic status, regardless of fluoridation status. This not only shows the minimal impact on “social equity”, but also the need for careful control for this factor in any study. The authors also state “mean DMFS among 10-15-year-old children was 24.4% higher for those children living within a single-parent family compared with children not in a single-parent family and this was statistically significant.” These results appear to negate the claim that fluoridation “promotes social equity in dental health” as promoters claim, but as also refuted by the York Review findings. This result shows clearly why promoters constantly rest their case on 5 year olds, who still have mostly their milk teeth. It also supports other studies showing no permanent benefit:
- A study by Master and Coplan in 1999 showed minimal differences in decay for children up to 12, and that the difference disappeared entirely by the mid to late teens (the Armfield and Spencer study used the 10-15 age group for results on permanent teeth);
- Hunt Eldridge and Beck, Journal of Public Health Dentistry, 1989, quoted by the NZ Ministry of Health as supporting their claim that fluoridation benefits adults, found no difference after 30 to 40 years of fluoridation exposure;
- Spencer et al 1996: a lifetime difference of only 0.12-0.3 DMFS, which is arguably not statistically significant – “Water Fluoridation in Australia” (1996) Community Dental Health 13 (Suppl 2), 27.
Interestingly, the authors stated that the results of no benefit in permanent teeth came as no surprise to them! The study also found a small benefit from fluoridation, for milk teeth only, even if fluoride toothpaste and fluoride tablet use was controlled for. However there is a critical factor never mentioned in the report, which would have a significant impact on the results: much of the unfluoridated water was tank (rain) water, which has no significant mineral content. The levels of calcium and phosphorus in water supplies has a significant impact in dental health; indeed early US studies “supporting” fluoridation showed, on independent analysis, that decay rates were (inversely) related strongly to the level of these minerals in the water, not the fluoride levels.
In the 2004 study, a total of 9988 children’s dental records from 1991 to 1995 were sampled at random, from school dental service records, based on birth date. Fluoridated children were sampled from the South Australian capital, Adelaide, while unfluoridated children were sampled from the rest of South Australia. The unfluoridated area comprised rural. This is significant because rural areas traditionally have poorer dental health than urban areas. Indeed promoters deliberately “stack” results by making this unequal comparison (Slade et al, Australia,(1996); McKay and Denniston, NZ (2004)). Socio-economic status was controlled for by a number of indicators. It is also significant that, although WHO methodology was followed, dentists recording the data knew the fluoridation status of the children, introducing potential bias in favour of fluoridation. Armfield and Spencer are, overall, clearly in favour of fluoridation, as they recommend, in conclusion, that fluoridated bottled water be given to young children (apparently unaware of the warning on fluoride tablet bottles, in both NZ and Australia, that no fluoride be given to children under 3).
Interestingly, the authors note that “The Australian Chapter of the International Bottled Water Association proposes that one reason why people are drinking bottled water is actually to avoid chemicals such as fluoride used in the treatment of public water supplies.”