October 20, 2020 4 min read
Fluoride is a naturally occurring form of the very common element fluorine. It is found all over the place–in water, food, plants, soil, rocks and so forth.
When your body takes in fluoride, it almost completely stored in your bones and teeth. It is known to help the mineralization process of your bones and teeth. It is also thought to help prevent, or lower the risk of, cavities.
With that basic understanding of what Fluoride is, why exactly would it help to prevent cavities?
First, let’s look at the basic formation, or cause, of a cavity. The word itself is related to the word “cave” and its basic meaning is a hole or a hollow space.
Your teeth are quite hard, on the outside, due to a layer of super-tough calcium. This calcium comes in a form known as “hydroxyapatite” which is a naturally occurring form of calcium that makes up the majority of your bones and teeth.
Some bacteria in your mouth create a lot of acid. This acid eats away at the enamel and removes minerals (mostly the calcium) from the teeth. This is called demineralization.
In a normal and healthy mouth, nature has developed systems to fight this acidity and to put the minerals back. This is called remineralization.
In simple terms, when things are in balance then the mineralization process is stable and your enamel stays strong. But when the bacteria grow out of balance and your mouth is too acidic, then the enamel is weakened and the cavity formation process starts.
Hydroxyapatite (the natural mineral that makes up most of your enamel) is made up of a few different elements (think of ingredients in a cake) and what fluoride does is to simply replace some of those elements (ingredients) to create a different mineral called “fluorapatite” that is also very hard and good at protecting your teeth.
Going back to our cake example, if you took out the vanilla flavor and substituted chocolate then you would still have a cake but just a different cake.
As a note, studies going back several decades point to the fact that fluoride is most effective in cavity prevention when it is directly applied to the teeth. This would suggest that water fluoridation may be less effective than thought.
Bottom line, the fundamental reason that fluoride is thought to help prevent cavities is that it is effective at remineralizing the enamel. When applied directly to the teeth, it helps to form a strong mineral (fluorapatite) that strengthens the enamel and repairs the damage done by bacterial acid and demineralization.