Prevalence of malocclusion and orthodontic treatment need in the United States: estimates from the NHANES III survey.

Data from the third National Health and Nutrition Examination Survey (NHANES III) provide a clear picture of malocclusion in the US population. Noticeable incisor irregularity occurs in the majority of all racial/ethnic groups, with only 35% of adults having well-aligned mandibular incisors. Irregularity is severe enough in 15% that both social acceptability and function could be affected, and major arch expansion or extraction of some teeth would be required for correction. About 20% of the population have deviations from the ideal bite relationship; in 2% these are severe enough to be disfiguring and are at the limit for orthodontic correction. In Mexican-Americans compared to the rest of the population, incisor irregularity and both severe Class II and Class III malocclusions are more prevalent, but deep bite and open bite are less prevalent. Application of the Index of Treatment Need to the survey data reveals that 57% to 59% of each racial/ethnic group has at least some degree of orthodontic treatment need. Over 30% of white youths, 11% of Mexican-Americans, and 8% of blacks report receiving treatment. Severe malocclusion is observed more frequently among blacks, which may reflect their lower level of treatment. Treatment is much more frequent in higher income groups, but approximately 5% of those in the lowest income group and 10% to 15% of those in intermediate income groups report being treated.