Fluoride in Water: What You Should Know

Water fluoridation programs have been adopted the world over to provide controlled levels of fluoride into the public water system. The primary goal is to promote good tooth health to as many as people as possible in as cost-effective a way as possible.

But what is fluoride? How does it help teeth?

And, most importantly, is it safe?

Fluoride in water


What Is Fluoride?

Fluoride is a naturally occurring chemical found in the earth’s crust, and is a component of mineral salts found in rocks, soil, plants, animals, and natural water sources.

The amount of fluoride found in a given water source depends on the rocks and minerals that source passes through or is surrounded by. This means the natural level of fluoride can actually be quite high — higher than recommended safe levels, even.

In some places, water fluoridation treatment actually involves removing natural fluoride to bring it down to a safe level.


How Does Fluoride Help Teeth?

The most important role of fluoride in oral health is preventing tooth decay.

Fluoride helps in two ways:

  • By reducing This is a process where the minerals in tooth enamel break down and the enamel itself dissolves. This leads to cavities.
  • By promoting remineralisation. This is when a damaged tooth rebuilds and strengthens the enamel.

Fluoride is used by the body to grow and strengthen minerals in teeth, specifically the enamel. Doing this protects the teeth from decay, and helps them heal during the early stages of decay to prevent further problems.


Why is Fluoride in Drinking Water?

Above we mentioned that fluoride is naturally occurring in some water sources. But we do we go out of our way to add fluoride to other sources?

Over the last 70 years, studies have shown that simply adding fluoride to public drinking water can greatly reduce the prevalence of tooth decay.

In children, this reduction can be as high as 47%. For adults, around 25%.

Studies find that for each $1 spent on water fluoridation, up to $18 is saved in avoided treatment costs. When water fluoridation was introduced into Victoria, $1billion was saved over a 25 year period.

This highlights not only the effectiveness of the campaign, but also the prevalence and sheer cost of tooth decay on the health system.

Water fluoridation helps protect teeth at all stages of life. This is one of the reasons why a broad, public distribution was chosen instead of something more targeted — say, fluoridating water at primary schools, to help protect children’s teeth from tooth decay.


Is Fluoride Safe?

Like anything, there are safe and unsafe levels of fluoride.

The goal of water fluoridation plans is to monitor water fluoride concentrations at levels which are both safe, and effective.

Most times this means adding carefully controlled amounts of fluoride to a water source. However, as pointed out above, this can also mean taking fluoride out of a water source. Natural fluoride levels can vary from place to place, and some perfectly natural water sources have fluoride levels that would be unsafe for prolonged exposure.

At the levels present in drinking water across Australia, fluoride is not shown to cause any health problems.

  • There is no evidence linking community water fluoridation and any form of cancer.
  • There is no evidence linking community water fluoridation and cognitive function. Some overseas studies had shown a link, but these studies were also conducted on water sources that had significantly higher levels of fluoride, and did not control for heavy metal contamination.
  • There is no evidence linking community water fluoridation and kidney problems.
  • There is no reliable evidence linking community water fluoridation and hip fractures, skeletal fluorosis, osteoporosis, or musculoskeletal pain.
  • There is no reliable evidence linking community water fluoridation and thyroid problems.

One potential problem that is well documented is dental fluorosis in children. This occurs when an excess of fluoride is consumed while teeth are developing, but before they appear through the gum — around 8 years of age.

This presents as a white discolouration of the teeth, either in patches or streaks. It doesn’t affect the health or function of the tooth.

There are a few simple ways to prevent this:

  • Use as little fluoridated toothpaste as possible when brushing your children’s teeth, and make sure they don’t swallow it. Swallowing toothpaste is thought to be the leading cause of fluorosis.
  • If your child is being fed on a formula mix rather than breastfeeding, check the ingredients and consult your doctor on the best option for you.
  • Do not use fluoride mouth rinse for children under six.


Combining Multiple Fluoride Sources

Since fluoride is in the water supply, is there any reason to use fluoridated toothpaste?

Simply put, yes.

The levels of fluoride in drinking water are kept low. They help to keep a supply of fluoride in the saliva to constantly coat the teeth.

Toothpaste, however, has significantly higher concentrations of fluoride (one of the reasons you’re not meant to eat it!), and is applied directly to the tooth.

The combination of water fluoridation and topical application of fluoridated toothpaste provides a powerful and complementary treatment to strengthen and protect teeth from tooth decay. Using both sources together provides superior protection than either on their own.