Fluoride is a mineral that occurs naturally and which can be found in some water supplies and certain foods. It’s very helpful for teeth as it reduces the risk of tooth decay. This is because every day teeth undergo a process called demineralisation and re-mineralisation. Whenever you or your child eats anything starchy or sugary, bacteria in the mouth feed off the remains and create acid. This acidic environment removes minerals from the tooth enamel including fluoride, phosphate and calcium during demineralisation. After a while the mouth becomes less acidic and some of the minerals are redeposited into the enamel. Having sufficient fluoride helps this process of re-mineralisation, making teeth more resistant to acid and sugars in the mouth.