Ingested fluoride, dental health and old age

By Ken Perrott 03/09/2014


dentistWhen we who are chronologically challenged get together we often discuss health – and sometimes compare notes.  But, strangely, I have never heard people discuss their dental health. Don’t know why, but I started to wonder if I was the only one with my particular problem.

These days I seem to visit my dentist quite often – but current tooth decay is never the problem. Its more likely to be tooth fracture – bits of teeth breaking away or chipping off. So I asked a couple of dentists if I was unusual – or is tooth fracture just another problem of old age.

Turns out I am quite normal, at least in this respect. Dentists do find tooth fracture is more common than tooth decay at my age.* To me this underlines an important fact – what happens in our youth can affect us for the rest of our life, and particularly in our old age.

This goes for our teeth, as well as our brain. Our teeth form and develop in our early years. So the damage we do during their development comes back to bite us, as it were, 60 or more years later. Just as child abuse or neglect can have psychological effects in old age, it can also have dental effects.

Nutritional deficiencies during these early years can increase risk of developmental defects of the teeth and dental caries throughout the rest of our lives. Because teeth development is completed by age 8 we are stuck with these defects for the rest of our lives.

Fluoride and teeth development

Fluoride deficiency can be a factor in tooth development defects. This is because it is a normal and natural part of the tooth mineral, the tooth apatite. Fluoride lowers the solubility of apatites and makes them stronger and harder. Consequently, fluoride deficiency in childhood weakens tooth enamel and can  produce a susceptibility to tooth fracture later in life.

I think it is important to realise this. Recently I heard someone claim that ingested fluoride only has an effect on developing teeth in children so was of no benefit to adults.  A very short-sighted understanding –  children turn into adults.

Another reason I think it is important to understand the importance of ingested fluoride to our teeth throughout our life is the propaganda from anti-fluoride activists claiming that ingested fluoride does not influence out teeth. They have taken on the scientific understanding of the reaction of fluoride at the tooth surface which inhibits demineralisation to argue that ingesting fluoride is like drinking sun tan lotion because the effect is, they claim, purely topical.

That is a misrepresentation – and one that causes  confusion when anti-fluoride campaigners make these claims in their submission to councils. (The Hamilton City Council even advanced this misunderstanding as accepted knowledge – see When politicians and bureaucrats decide the science).

A more balanced understanding of the science shows the beneficial effects of fluoride intake is both systemic (via ingested fluoride) and topical (via the surface reaction at the tooth surface). Incorporation of fluoride into the bioapatites forming our teeth and bones strengthens and hardens them. This occurs during tooth development. Because the tooth material is stronger and harder it is less likely to suffer from fractures, scratching and similar damage.

On the other hand, fluoride intake helps protect existing teeth from decay because of the surface reaction inhibiting demineralisation of the teeth. Just from a chemical perspective the presence of calcium, phosphate and fluoride in saliva and tooth biofilms helps prevent tooth decay resulting from acid attack and demineralisation. But from a mechanical perspective if our teeth are harder and stronger there will also be fewer physical defects providing sites for the chemical acid attack.

Fluoride benefits from ingestion and surface effects

Anti-fluoride propagandists have worked hard to deny any benefits of fluoride on dental health. Often they fall back on the argument that any benefits arise only form a “topical” effect. They usually interpret this to mean tooth brushing or dental topical applications.

However, consumption of fluoridated water and food enables transfer of fluoride to saliva and biofilms on the teeth. This fluoride, together with calcium and phosphate on the saliva, reduces acid attack on the teeth and so helps prevent tooth decay. Because fluoride concentrations in saliva decrease within an hour or so after brushing, fluoridated water complements use of  fluoridated toothpaste. We are in more regular contact with food and water than we are with toothpaste

But ingestion of fluoride in food and drink during tooth development in children also helps harden and strengthen tooth enamel. This benefits a person’s teeth throughout their life by helping prevent  and tooth fracture and physical defects. Harder tooth enamel will reduce tooth decay by preventing physical formation of sites for it to take hold, even though the acid attack is itself a chemical, surface effect.

So, even the chronologically challenged benefit from community water fluoridation. And you young ones – remember one day you are going to be old and your quality of life may well depend on the community water fluoridation you had access to as a child.


*Apparently tooth decay can still return as a major problem in old age because the withdrawal of gums from the tooth roots open new sites for decay. This is known as root caries.

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