Fluoride is the best-evidenced protection we have against decay. How it works, the right concentration by age, and the safe amount for children.
Most people choose toothpaste by flavour, brand or a whitening claim. Yet one ingredient does the real work, printed in small type on the back of the tube: the fluoride concentration. Knowing that number is almost the whole of choosing a toothpaste.
How fluoride protects the tooth
Bacteria in the mouth produce acid as they break down sugar. That acid draws calcium and phosphate out of the enamel surface — demineralisation. Saliva then neutralises the environment and carries those minerals back. Dental health is the balance of these two.
Fluoride tips that balance towards repair. It joins the returning minerals to form a crystal far more resistant to acid, and it also slows the metabolism of acid-producing bacteria. It speeds repair and reduces the attack at once.
The effect is from contact, not swallowing
For many years fluoride was thought to work only from within, while the tooth was developing. What is known today is that the main protection comes from fluoride contacting the tooth surface several times a day. That is why toothpaste works when it is applied and left.
The practical consequence matters: rinsing thoroughly after brushing washes away the fluoride reserve the paste has left. The correct approach is to spit out the excess and not rinse. That single change of habit makes more difference than changing brand.
The right concentration for adults
The standard in adult toothpaste is 1,450 ppm fluoride. That is enough for protection and is what most brands use. If the tube does not state a ppm value, the product is not suitable for the job.
In patients at high risk the dentist may move to a 5,000 ppm prescription paste. These are used where there is dry mouth, exposed root surfaces or a history of recurrent decay; they are not for everyone.
In children, is it the amount or the concentration?
Both, but in this order: the concentration should suit the age and the amount should be small. Current practice is to use an age-appropriate concentration in a small amount, rather than a low-fluoride paste.
- From the first tooth to age 3: a smear the size of a grain of rice
- Ages 3–6: a pea-sized amount
- Age 6 and over: a thin strip along the brush head
At these ages brushing must be supervised and the child prevented from eating the paste. Keep the tube out of reach in the bathroom.
What is fluorosis, and is it a real risk?
Fluorosis is the appearance of white flecks or lines in enamel, caused by taking in too much fluoride over a long period while the teeth are still forming in the jaw. It can only develop in unerupted teeth — roughly before the age of eight.
With the correct amount, fluorosis from toothpaste is not seen in practice. The risk comes from a child regularly swallowing paste, which is why amount and supervision are stressed. Avoiding fluoride, by contrast, clearly raises decay risk — a far commoner and more serious problem.
Do fluoride-free pastes achieve anything?
Fluoride-free pastes mechanically remove the soft surface layer, so they do clean. They do not, however, contribute to remineralising enamel. Alternatives such as hydroxyapatite are being studied, but the level of evidence is not comparable with that for fluoride.
Unless there is a medical reason, choosing a fluoride-free paste means voluntarily giving up the best protection available.
Isn't the fluoride in water and food enough?
In most parts of Türkiye the fluoride level in mains water is low, below what would provide protection. Antalya is no exception, and relying on the water instead of toothpaste is not sound. Tea leaves and seafood contain fluoride, but not in amounts that create protection at the tooth surface.
Fluoride supplements (drops or tablets) are given only after professional assessment, with all of the child's fluoride sources taken into account. Starting a supplement on your own does carry a genuine fluorosis risk, unlike toothpaste.
How much do the other ingredients matter?
Abrasives, foaming agents and flavourings determine comfort in use but provide no protection. Pastes labelled "whitening" remove surface stain; they do not change the tooth's own colour. Continuous use of highly abrasive products can wear the root surface exposed by receding gums.
Desensitising ingredients — potassium nitrate, stannous fluoride — have a genuine function and are worthwhile for patients with sensitivity. Otherwise the number to check when choosing a paste remains the ppm value.
