By Guest Author 08/01/2018 7


Conspiratorial people love to claim that the government adds fluoride to water and toothpaste in some dastardly plan to make us all sleepy slaves, helpless to resist their evil bidding.

The truth, however, is far less scandalous and far more reassuring – fluoride is your friend, my friend, and geochemistry is how we know this!

Teeth are comprised of a calcium phosphate mineral called apatite – which is the most common phosphate mineral – it’s got what plants crave, which is why fertiliser brands give themselves names like “Blood and Bone”.

Like most minerals, apatite has different compositional chemical varieties, known as “end members”, and the end member of the apatite that our teeth are made from is called hydroxyapatite. Hydroxyapatite is structurally rather weak, and so it is easily penetrated and dissolved by acids from plaque, otherwise known as tooth decay.

Luckily, there is a different end member of apatite which is much stronger and can step in to shoulder hydroxyapatite’s burden, taking one for the team. This guy is fluorapatite, and has a much stronger crystal structure, which means that the introduction of fluoride to hydroxyapatite fills in the weak spots and remineralises the teeth, reversing lesions in damaged teeth. Topical fluoride, such as that from toothpaste, increases the size and rate of growth of the apatite crystals, making your teeth great again, and making them a bit less susceptible to further decay. When you ingest fluoride via drinking water, it absorbs into the bloodstream and is carried to new teeth sites, where the fluoride reacts with the hydroxyapatite, resulting in the developing crystals growing as fluorapatite – and therefore much stronger.

So take off your tinfoil hats, brush your teeth and rejoice, because science proves that fluoride is not out to get you!

Chelle Fitzgerald is a geology student and science writer living in Dunedin, New Zealand. She loves Jurassic Park and red wine. 

This article was originally published on Critic te Arohi, Otago University’s student magazine. Artwork is by the wonderful Ceridwyn Giddens – check out her work here! 


7 Responses to “Science Tank | Fluoride”

  • “Chelle Fitzgerald is a geology student and science writer living in Dunedin, New Zealand”

    Chelle lives in fluoridated Dunedin. Enough said. She has obviously been affected by the Dunedin’s fluoridated water.

  • Of course she’s been affected by the fluoridated water.

    Her teeth are stronger and less prone to decay because of the fluorapatite they contain.

    That’s the point of the article.

  • Kane, it is 2018, how about turning over a new leaf and swearing off posting trolling comments…

    • Peter, how about when you show up to hear Prof Connett this year you ask a question as opposed to just taking a recording and then defaming him on Jesse Mulligan’ s radio programme? Show a backbone maybe.

    • Chelle, should the recommended concentration level of fluoride be 0.7 – 1ppm per the NZ MOH or 0.7ppm per the US HSS recommendation? Auckland reduced the level to 0.7ppm on 26 January 2016.

  • Fluoride shouldn’t be prescribed by lobbied-legislators, delivered by water employees and dosed based on thirst and not age, health, weight and need. Everyone gets a different dose depending on the amount of water consumed.

    Fluoride should be prescribed to individuals by medical professionals, not by communities.