Enamel which has had fluoride during development is no more resistant to decay than unfluoridated enamel, so the justification for making children swallow fluoride for 50 years was shown to be incorrect (CDC 1999).
The major effect of fluoride is topical (direct contact with the tooth) not systemic (swallowing). If fluoride is in contact with the tooth for a long enough time and in sufficient concentrations, it can slow down early decay areas by slowing down calcium loss from the early cavity.
Water fluoridation does not generally provide sufficient levels of fluoride in the saliva to have any significant effect on tooth decay. These levels are achieved after using fluoride toothpaste, which is 1000 times more potent.
Is tooth decay a serious problem?
Tooth decay rates have dropped to very low levels in all developed countries, whether fluoridated or not (in New Zealand the average 13-year-old has had one filling in their permanent teeth).
There are groups which appear to be particularly at risk of a high decay rate, and this comes down primarily to poor diet and oral hygiene habits among those groups. They exist both in fluoridated as well as unfluoridated areas, it is not water fluoridation that defines these groups, nor does it significantly protect the teeth of such groups.
Can't we take fluoride tablets instead? Surely they're just as good.
Swallowing fluoride tablets is of questionable value as this does not result in elevated salivary fluoride to any level of benefit. They are no longer recommended due to toxicity.
If we brush our teeth with toothpaste with fluoride, isn't that enough?
Yes. Fluoride toothpaste contains 1000ppm fluoride whereas fluoridated water contains only 0.85ppm - over 1000 times less. It is implausible that this tiny amount of fluoride could provide additional benefit.
Where else has water fluoridation?
The US accounts for over half the fluoride drinkers in the world. Few other countries have over 50 per cent fluoridation. In fact 80 per cent of the developed world is unfluoridated, including 97 per cent of continental Europe.
How do we know fluoridation is effective?
Most of the world does not have fluoridation and their teeth are just as good, if not better, than ours. Tooth decay rates across fluoridated and non-fluoridated New Zealand shows some unfluoridated places are better than the fluoridated areas and vice versa. Nowhere has tooth decay gone up when fluoridation has stopped such as Ashburton, Timaru, New Plymouth, Waipukurau etc.
Can fluoridated water cause toxic effects?
Yes. The toxic limit for long term ingestion is 0.05mg per kilogram of body weight a day (ATSDR 2003). Given the fluoride ingested from other sources such as food, drink and toothpaste, the toxic limit is easily exceeded by most children under 8 years of age and many adults (ESR report 2009), and fluoridated water simply adds to the risk of overdose.
Fluoride is linked to many adverse health effects such as lowered IQ, underactive thyroid, increases in hip fractures, arthritis. Overseas studies have found 1 - 5 per cent of people are particularly sensitive to fluoride.
Can a person have too much fluoride in their body?
Yes. Fluoride is not an essential nutrient, so there is no need for any fluoride to be ingested at all. Of the ingested fluoride, 50 per cent stays in the body, predominantly going to bones and teeth, but also circulating through the blood to all the cells in the body.
Chronic accumulation of low levels can lead to bone and joint disease, diabetes, thyroid problems, etc, especially if the toxic chronic ingestion limit of 0.05 mg/kg/day is exceeded. For this reason, the WHO stresses that total fluoride levels should be measured at the individual level in areas that want to fluoridate the water to ensure that fluoride overdose is not occurring. This is not happening.
Is there a "downside" to water fluoridation?
Large scientific reviews raise many red flags about health issues and highlight many areas where knowledge is poor and better research is required.
https://zen.nzherald.co.nz/v2/images/datepicker.png
It is the dose which determines whether a person will have harmful health effects, regardless of what the water concentration is, and any responsible health body should monitor fluoride levels at the individual level, as recommended by WHO.
- Mr Litras, a Wellington dentist, is the founder of FIND (Fluoride Information Network for Dentists) which aims at independently and objectively assessing fluoride research. He was a member of the New Zealand Dental Association for 35 years until resigning recently over his differing opinions on fluoride.
