The hard enamel surface of your teeth protects them, much like the skin of an apple protects the fruit inside. This demonstration from Star Smilez shows what can happen to teeth when a cavity develops and allows bacteria inside.
Just like an apple’s skin, enamel is an important barrier for keeping bacteria out of your teeth. When that enamel shield is broken – like when you get a cavity – it opens the door for bacteria to get inside your teeth and cause decay. That’s why it’s important to brush your teeth twice a day with a fluoride toothpaste to remove germs and strengthen your enamel.