Tooth decay, also known as cavities, is the second most prevalent disease in the United States. (The common cold is first.) Tooth decay occurs when plaque, the sticky substance that forms on teeth, combines with the sugars and/or starches of the food we eat. This combination produces acids that attack tooth enamel.A person can get cavities at any age, they are not just for children. As people age, they can develop cavities as your tooth enamel erodes, and dry mouth due to age or medications can also lead to cavities.The best way to prevent tooth decay is by brushing twice a day, flossing daily, and going to your regular dental check ups. Eating healthy foods and avoiding snacks and drinks that are high in sugar are also ways to prevent decay.