Is Fluoride Safe? What the Evidence Says About Tap Water and Toothpaste
- Star Light Dental
- July 23, 2026
- [email protected]
Fluoride has been added to Sydney’s water supply since 1968, and it is in almost every toothpaste on the supermarket shelf. It is also the subject of a steady stream of alarming claims online, so it is no surprise that parents ask us whether it is safe.
Here is what fluoride does, what the evidence says, and how to use it sensibly.
1. What Fluoride Actually Does
Tooth enamel is in a constant tug of war. Acids from plaque and from food dissolve minerals out of it, and saliva puts them back. Fluoride tips that balance in favour of repair. It helps minerals return to early areas of damage, it makes the rebuilt enamel more resistant to acid, and it slows the bacteria that produce the acid in the first place.
Most of the benefit comes from fluoride being present in the mouth in small amounts, often. That is exactly what tap water and toothpaste provide.
2. What the Evidence Says About Tap Water
Australia’s National Health and Medical Research Council carried out a comprehensive review of the evidence and concluded that community water fluoridation, at the levels used in Australia, is a safe and effective way to reduce tooth decay. It found that fluoridation reduces decay by roughly a quarter to almost half in children and adolescents, and by around a quarter in adults.
The review found no reliable evidence that fluoridation at Australian levels causes cancer, affects intelligence, damages bones or causes any other health problem. Around nine in ten Australians now have access to fluoridated water.
3. What About the Studies on Children’s Development?
You may have seen headlines about overseas research linking fluoride with lower IQ in children. Those findings relate to fluoride levels more than double those used in Australian water supplies, usually in regions where fluoride occurs naturally in groundwater at high concentrations. Health authorities here and overseas have been clear that those results do not apply to the much lower, controlled levels in our water.
4. The One Real Side Effect: Fluorosis
If young children swallow too much fluoride while their adult teeth are forming, faint white flecks can appear on those teeth. This is dental fluorosis. In Australia it is almost always very mild, purely cosmetic and often visible only to a dentist. It is caused mainly by swallowing toothpaste, not by drinking tap water, which is why the toothpaste guidelines for children matter. Our article on white spots on teeth explains the other causes.
5. How Much Toothpaste for Children?
- Under 18 months: brush with water only, unless a dentist advises otherwise.
- 18 months to 5 years: a pea-sized amount of low-fluoride children’s toothpaste, twice a day.
- 6 years and over: a pea-sized amount of standard fluoride toothpaste.
- Teach children to spit, not rinse, and keep the tube out of reach so that it is not eaten as a treat.
Adults at high risk of decay, for example with a dry mouth, may benefit from a high-strength fluoride toothpaste or a professional fluoride treatment. Ask us whether that applies to you.
6. Filters, Bottled Water and Tank Water
- Most jug and tap-mounted carbon filters do not remove fluoride.
- Reverse osmosis systems and distillers do remove it.
- Most bottled water contains little or no fluoride.
- Rainwater tanks are not fluoridated.
If your household drinks mainly bottled, tank or reverse-osmosis water, mention it at your check-up. It raises the risk of decay, especially for children, and we can suggest ways to make up the difference.
Questions About Fluoride for Your Family?
Ask us at your next check-up at Star Light Dental in Prestons. We are happy to talk through the evidence and tailor the advice to your family. Call (02) 9432 2833 or book online.
This article is general information based on the published position of Australian health authorities at the time of writing.