Most people realize that cavities are unhealthy, but many do not understand just how prevalent of a problem tooth decay actually is. The Centers for Disease Control and Prevention (CDC) now reports that as many as 19 percent of children and 26 percent of adults have untreated cavities. When left untreated, tooth decay can cause a variety of aesthetic and medical issues that will require comprehensive treatments. These are just some of the reasons that everyone should know about the importance of regular dental treatments and how important annual appointments are when it comes to finding and treating cavities. The easiest way to describe a cavity is a hole in one's tooth. These will develop in a number of stages beginning with harmful bacteria being left in the mouth. Certain substances such as sugar will cling to teeth and gums after being ingested. When it is not removed by brushing or flossing, then these different substances will develop into harmful bacteria. In turn, this bacterium will eat away at the outer layer of enamel on the teeth. Cavities occur when the damage has penetrated the outer layer of the teeth, but there are quite a few different types of damage that can take place with tooth decay.