The dental caries is not a problem only of children. Adults of all ages can have cavities too. The causes of tooth decay are the same for everyone, regardless of age. Caries results when the bacteria in the plate are fed with carbohydrates (sugar and starch) in our diet to produce acids that cause cavities.
However, the nature of the caries problem does change somewhat as people get older. Adults are more likely to have cavities around old fillings, and as many adults grew up without the benefits of fluoride, they have more fillings. Tooth decay is also common among older adults. Caries in the root occurs when there is recession of the gums which exposes the softer surface of the root, which suffers from decay more easily than tooth enamel.
Dry mouth also promotes tooth decay. This condition, called xerostomia, occurs when the amount of saliva is greatly reduced. It can be caused by many types of medications (such as antihistamines, antihypertensive , and antidepressants) or by radiation therapy to the head or neck. Saliva is needed to lubricate the mouth, take away food and neutralize the acids produced by the plaque. If allowed to continue, dry mouth can lead to rampant tooth decay. If you think you have this problem, be sure to check with your dentist or doctor. They can recommend artificial saliva and fluoride products to help prevent tooth decay.