At the levels used in Australian drinking water and toothpaste, fluoride is safe, and it is one of the best-supported ways to prevent tooth decay. That is the conclusion of the National Health and Medical Research Council (NHMRC), which reviewed the research in 2017. The one effect of too much fluoride that shows up in Australia is a cosmetic one, faint white marks on teeth, and the recommended doses are set to keep even that mild.
Fluoride worries spread easily online, so this page sets out what the Australian review looked at, what it found, and how much fluoride makes sense at each age.
What the NHMRC review concluded
The NHMRC is the country's main body for health research funding and advice. Its 2017 public statement found that community water fluoridation reduces tooth decay by 26% to 44% in children and adolescents and by 27% in adults. It supports states and territories fluoridating water within a range of 0.6 to 1.1 milligrams of fluoride per litre.
The review also looked beyond teeth. It reported reliable evidence that fluoridation at current Australian levels is not associated with cancer, Down syndrome, cognitive dysfunction, lowered intelligence or hip fracture, and no reliable evidence of a link with conditions such as osteoporosis, skeletal fluorosis or thyroid problems. Its overall description of water fluoridation was safe, effective and ethical.
Fluoridated water reaches most of the country. According to the Australian Institute of Health and Welfare, the NHMRC estimated in 2017 that around 89% of Australians had access to it.
Why the dose is the whole point
Almost anything can cause harm in a large enough amount, and fluoride is no exception. The safety finding applies to the regulated range in Australian water and to toothpaste used as directed. It does not mean that more fluoride is better. That is why the guidance below is specific about amounts, particularly for small children who are still learning to spit.
Fluorosis: the effect the guidelines are built around
Dental fluorosis can develop when a child takes in more fluoride than needed while the adult teeth are still forming under the gums in early childhood. Once a tooth has come through, it cannot develop fluorosis. The NHMRC statement notes that almost all fluorosis in Australia is very mild or mild, appearing as faint white flecks or lines, and that it does not affect how teeth work. Very mild to mild fluorosis has even been linked with some protection against decay in adult teeth.
White marks can have other causes, including early decay and enamel that formed poorly for other reasons. Our guide to white spots on teeth explains how a dentist tells them apart.
How fluoride stops decay
Enamel is constantly losing and regaining minerals. After you eat or drink something sugary, plaque bacteria make acid that dissolves a little of the surface. Saliva then brings calcium and phosphate back. Fluoride at the tooth surface speeds up that repair and leaves the rebuilt enamel more resistant to the next acid attack. Regular low doses, from water and twice-daily brushing, keep that process working in your favour. The way decay starts and spreads is covered in our article on how cavities form.
How much fluoride toothpaste to use at each age
Australian guidance, summarised by the Australian Dental Association, sets out toothpaste use by age:
- Under 18 months: no toothpaste, unless your dentist advises otherwise.
- 18 months to 6 years: a smear of low-fluoride children's toothpaste, with an adult supervising.
- 6 years and over: a pea-sized amount of standard fluoride toothpaste, twice a day.
At every age the habit is the same: spit out the foam, do not swallow it, and do not rinse straight away, so a little fluoride stays on the teeth.
Extra fluoride for people at higher risk
Some people get more decay than average, for example because of a dry mouth, exposed roots, braces or a history of new cavities. For them, a dentist or OHT may suggest a fluoride varnish painted onto the teeth, which the Australian Dental Association guidance allows up to four times a year for people at moderate or high risk. Adults at high risk may also be advised to use a high-strength fluoride toothpaste, which should only be used on professional advice.
| Source | What it does | Who it is for |
|---|---|---|
| Fluoridated tap water | Steady low-level protection through the day | The whole community |
| Fluoride toothpaste | Daily repair of early enamel damage | Everyone, in the amount set for their age |
| Fluoride varnish | A higher-strength application at the dental visit | Children and adults at moderate or high decay risk |
| High-strength fluoride toothpaste | Extra protection used at home | Adults at high risk, on professional advice only |
Common questions
Is fluoride-free toothpaste a safer choice?
It removes the ingredient with the strongest evidence for preventing cavities. If you are weighing it up, our articles on fluoride-free toothpaste and hydroxyapatite toothpaste compared with fluoride look at the evidence for the alternatives.
Can adults get too much fluoride from water and toothpaste combined?
Normal use of fluoride toothpaste together with fluoridated tap water sits within the levels the NHMRC considers safe. The caution about amounts mainly concerns young children who swallow toothpaste while their teeth are forming.
My child already has white marks. Is that fluorosis?
It might be, but early decay and other enamel conditions can look similar. A dentist or OHT can check and advise whether anything needs doing.
If you have questions about fluoride for yourself or your children, bring them to your next check-up at Lumi Dental, where our dentists and OHTs can look at your decay risk and suggest what fits.
