Editor;

Let's talk about teeth. Tooth decay is one of the most widespread chronic diseases and seen more often to affect children, seniors and individuals with lower income.

Fluoridation of drinking water is an accepted measure to protect public health by preventing tooth decay. Fluoridation is supported by extensive scientific evidence and endorsed by more than 100 health agencies worldwide. Fluoride has been safely added to drinking water for more than half a century. The important advantage of water fluoridation is that it benefits all, regardless of age, income, education, employment, or dental insurance status.

Fluoride is not a drug. Fluoride comes from fluorine, a commonly occurring mineral found in soil, air, plants, animals and water. It is the 13th most abundant element on the earth's crust. The United States National Research Council considers fluoride to be a "beneficial element for humans" (NRC, 1989).

It is all a matter of amount. Many things are good for us in small amounts and harmful in large amounts. This is particularly true of the minerals that we need to be healthy. Iron helps to make our red blood cells, but too much iron will poison our muscles and can cause heart failure. Zinc, manganese, copper, molybdenum iodine, chromium, selenium and fluoride are all essential trace elements.

There is no argument that too much fluoride is not good. As more dental products containing fluoride have come along, the recommended amounts for fluoride in municipal water have decreased.

Too much fluoride may result in fluorosis in developing teeth. In Grey and Bruce, all children's teeth are examined by public health dental hygienists at Kindergarten, Grade 2 and in some schools Grade 4. We do not see dental fluorosis in the children drinking Owen Sound water.

Some areas of Bruce County have high naturally occurring fluoride in the ground water. These areas are well known to public health and the local dental practitioners. Communities with naturally occurring fluoride generally have less decay.

Fluoride has two main actions on tooth health. Topical (surface) fluoride increases the tooth's resistance to decay. This fluoride is available in various dental products such as toothpastes, mouthwash and rinses. Systemic (ingested) fluoride is used in the development of teeth and bones. Systemic fluoride strengthens the enamel and helps create a tooth surface more resistant to decay. Dentists recommend a combination of both systemic and topical fluoride to obtain maximum benefits.

The anti-fluoride advocates dismiss a huge body of science that supports this safe and cost-effective public health measure. Instead, they draw on a handful of studies to prop up their claims. Let's look at some of the specifics.

Campbell River BC is offered as proof that removing fluoride from drinking water does not result in increased decay in the children's teeth. What they don't say is that after the end of the water fluoridation a universal fluoride varnish program was provided for the children. Regular application of fluoride varnish is very effective to protective children's teeth. Well, why not the same here? Campbell River was a small military base. That kind of a program would be prohibitively expensive in Owen Sound. Hamilton currently spends about $1.5-Million a year to fluoridate their municipal water supply. Health economists estimate that it would cost Hamilton $17-Million per year to switch to topical fluoride varnish done by public health and if done through the dentists, it would be about $33M. The fluoridation of Owen Sound water costs between $15 and $20 thousand dollars a year. Every $1 invested in adding fluoride to drinking water saves $38 in dental care. (American Dental Association)

Fluoride's effect on thyroid function? In the 1960s, researchers looked to treat over-active thyroid by using high doses of fluoride to block the absorption of iodine. It was known that the absorption of iodine is affected by high levels of fluoride, not surprising as these two minerals share similar characteristics. This effort was abandoned as more effective treatments for hyperthyroidism were developed. The amounts of fluoride used were considerably higher that levels found in municipal water.

Again, amount is the issue in the oft-cited studies from China looking at the effects of fluoride on IQ. There were significant amounts of fluoride in the water, far beyond what we use. Worthy of mention, those studies also identify low iodine levels, air quality from the burning of high fluoride coal and the presence of arsenic and lead which are all factors that can affect IQ.

It is an exaggeration to state 97 per cent of European countries have banned water fluoridation. Many countries do not fluoridate their water but instead add fluoride to their table salt and milk to get the benefits it offers, among them Austria, France, Germany, Spain, and Switzerland.

Not only was fluoridation approved in earlier plebiscites by Owen Sound residents, we share a set of values to support actions that benefit the greater good. While we value individual rights, we accept that some public policies put the common good above the desires of individuals. Fluoridation of the water supply fits into this thinking.

In all this discussion, where are those that are most vulnerable? The cost of removing water fluoridation would be felt most by lower income and other health-disadvantaged populations, who already experience poorer oral health and face significant barriers to dental care.

Still not sure? Pick up the phone and call your dentist.

Hazel Lynn, MD, FCFP, MHScc

Medical Officer of Health