Cavities are the breakdown of teeth due to bacteria, also known as tooth decay. It’s common for people to have cavities without knowing they do because they don’t typically cause a lot of discomfort until they get worse. The more time that passes, the worse the cavity will become. If you wake up with a toothache or feel a sharp pain in your mouth while eating or drinking, it’s quite possible that you have developed a cavity and should schedule an exam with your dentist.