The average adult between the ages of 20 and 64 has 3.28 decayed or missing teeth, according to the National Institute of Dental and Craniofacial Research. In addition, 92 percent of adults have had some type of cavities or caries.
Approximately 26 percent of adults between the ages of 20 and 64 have untreated decay and are in need of dental care. Adults in this age group also have approximately 13.65 decayed surfaces in their mouths. Approximately 5 percent of all adults have no teeth in their mouths whatsoever. Current and former smokers are at more risk for decay and cavities.