The case for fluoridated water

FILE

It's an issue that sparks plenty of debate - and there's an array of information out there, some accurate and some not. Rebecca Malcolm found answers to some commonly asked questions

Is there a difference between fluoride found naturally in water and fluoride that is added to water?

There is no difference. The fluoride ions in water are exactly the same regardless of whether they come naturally from rocks or are added as calcium fluoride or sodium silicofluoride.

How does fluoride help my teeth?

Fluoride works in three ways. It makes teeth more resistant to decay by strengthening the tooth surface, it interferes with the growth of the bacteria that cause cavities and it helps to repair the early stages of tooth decay. It can help strengthen baby teeth before they come through the gums by building fluoride into their structure. The main effect is when teeth erupt through the gums. If fluoride is present in saliva, teeth will continually be exposed to small levels of fluoride, which helps strengthen the tooth surface.

Is tooth decay a serious problem?

Internationally, decay rates have been decreasing over the last 20 years. However, tooth decay is still a significant health problem, particularly in communities with insufficient fluoride in their water.

Tooth decay will result in the life-long repair of teeth or tooth loss. Decay causes pain and loss of self-esteem and it also costs individuals and the community to treat it. Approximately $500 million is spent in New Zealand on dental treatment. The largest proportion of this is treating dental decay.

Dental pain can stop a person from eating, working and sleeping which affects their whole wellbeing. Decayed teeth can affect people's self-esteem and confidence about the way their teeth look or their bad breath.

Although tooth decay remains a common disease, it is largely preventable. Dental decay does not have to be a fact of life - prevention is possible and fluoridation, along with a healthy diet, is the most cost-effective way to achieve this.

Can't we take fluoride tablets instead? Surely they're just as good.

No. The benefit of fluoride tablets is limited as they don't provide constant small doses through the day and are more expensive over time than water fluoridation. The fluoride in the saliva from a tablet lasts only three hours, and would give less than 1 per cent of the fluoride available from food and drink in a fluoridated area. They need to be taken daily and chewed, which is difficult for children. Public health says water fluoridation is more effective because it is taken regularly throughout the day in the water used to drink and cook with irrespective of the consumer's social, economic or physical status.

If we brush our teeth with toothpaste with fluoride, isn't that enough?

Water fluoridation doesn't replace brushing teeth, regular dental check-ups or a low-sugar diet. But not everyone is brushing their teeth twice daily with the right toothpaste. The 2009 New Zealand Oral Health survey found only about 65 per cent of people brushed twice a day using fluoride toothpaste, slightly less for children. The fluoride from toothpaste and that from drinking water go hand in hand. Some is taken up by bones and teeth. When fluoride is ingested regularly when teeth are developing, it is deposited across the tooth's entire surface and this slows down decay. Because of this, tooth decay in fluoridated areas progresses more slowly.

Where else has water fluoridation?

About 370 million people in 27 countries have fluoridated water supplies and an estimated 40 million people drink water with naturally-occurring fluoride at the optimal level. Other countries use fluoridated salt or milk.

How do we know fluoridation is effective?

The effectiveness has been documented in scientific literature for well over 50 years. Data from the 1930s and 1940s shows children drinking naturally fluoridated water had lower decay rates than children consuming water without fluoride. Studies have also shown that when communities stop fluoridation, there is a reversal of the benefits, an increase in decay rates and a large increase in the number of baby teeth extracted. Most recent studies continue to show that the difference between fluoridated and non-fluoridated areas continues to be significant throughout life. The World Health Organisation, Public Health Commission, Ministry of Health and Environmental Science and Research have all supported its safety.

Can fluoridated water cause toxic effects?

It is impossible to experience fluoride toxicity from drinking water at the optimally fluoridated levels planned. An adult would have to drink several thousand glasses of fluoridated water in one sitting to get an acutely lethal dose of fluoride. In excessive quantities fluoride too can be toxic, but, at the very low concentrations (0.7 ppm to 1 ppm) used in water fluoridation it is not toxic, even when used over a lifetime.

Can a person have too much fluoride in their body?

Yes, like vitamins and other dietary supplements. In countries where there are extremely high levels of fluoride, it can cause skeletal fluorosis but this requires taking in much more fluoride than anyone in New Zealand would be exposed to.

What towns have fluoridated water supply in our region?

The Whakatane town, Ohope, Taupo Central, Taupo South, Turangi and Tokaanu water supplies have fluoridated water supplies.

Is there a "down side" to water fluoridation?

Numerous large scientific reviews over the past 60 years and ongoing monitoring of all new, relevant scientific studies continue to confirm that water fluoridation is effective and safe - and not linked to any health risks. The only recognised adverse effect is the possibility of mild fluorosis, which appears as small white lines or white spots on teeth. It is harmless, usually un-noticeable and does not affect the health of the teeth.

- Information provided by the Ministry of Health and Toi Te Ora Public Health.

HOW MUCH FLUORIDE?
Water from the Waipa Spring (Eastern areas) has about 0.3ppm naturally.
Water from the Wai-iti Spring (Rotoiti) has about 0.4ppm naturally.
The rest of the Rotorua water supplies has less the 0.2ppm naturally.
The optimal level is between 0.7ppm and 1.0ppm.
Measurements in parts per million.
- Figures supplied by the Rotorua District Council