Acid makes holes in the teeth. The acid is made when sweet foods mix with germs in your mouth.
It is not possible to prevent cavities or gum problems by trying to kill all of the germs in your mouth. There are too many — and some germs are good for you. The important thing is to keep the germs from getting together and making a film or coating on your teeth.
This film on the teeth is called plaque, but you do not need to use this word. Every morning we can all feel a ‘furry film’ on our teeth. This film must not be allowed to stay on the teeth! It will mix with sugar and make acid. Worse, if it stays in a group (or ‘colony’) for more than 24 hours, it will mix with saliva, harden, and make tartar.
The main reason for cleaning teeth is to break up these colonies so they cannot make acid. Also, if you forget to clean your teeth, tartar will form, and you will need a dental worker to scrape it off. This is why it is important to clean your teeth at least every 24 hours, so the tartar can never form on your teeth.