With the common cold being the only disease more rampant, tooth decay is one of the world’s oldest and most widespread diseases. In fact, it is a problem for more than 90% of US adults over age forty. To best understand dental decay, you should think of your mouth as an ecosystem where living organisms interact with everything in it and the fact that tooth decay is an infectious disease. And if you want a healthy ecosystem with good dental and oral health, then you need to understand what habits are required for obtaining this goal. You must form and execute a plan of action for preventing tooth decay.