A Sumerian text from 5000 BC describes “tooth worms” as the cause of dental decay. While bacteria, not tooth worms, are the actual cause of dental decay; they were correct in theorizing that a living organism in the mouth is the source. There are as many as 500-650 different species of bacteria in your oral cavity. They live in the biofilm which covers all the surfaces of the mouth. A great way to prevent dental decay is to brush, floss, and use an antibacterial mouth rinse daily. Finally, go for a dental cleaning and exam at least twice annually.