The prevalence of clinically meaningful malocclusion among US adults

The primary purpose of this study was to statistically evaluate age, ethnic and sex differences in the prevalence of clinically meaningful malocclusions among adults.

A random sample of 8804 untreated US adults between 17 and 46 years of age was selected from the Third National Health and Nutrition Examination Survey data.

Three ethnic (non-Hispanic White, non-Hispanic Black and Mexican Americans) and three age (17-26, 27-36 and 37-46 years) groups were evaluated. Subjects with and without clinically meaningful malocclusions were categorized based on the established cut-off values. Chi-square analyses were performed to determine differences in prevalence.

The prevalence of clinically meaningful mandibular incisor irregularity, overjet and overbite increased significantly (P < 0.05) with age, while posterior crossbite decreased. There were statistically significant ethnic differences in the prevalence of incisor irregularity, overbite, overjet, open bite and reverse overjet. Males had a significantly higher prevalence of clinically meaningful mandibular incisor irregularity, overbite, open bite and reverse overjet than females. One-third of US adults exhibited no clinically meaningful malocclusions.

There are age, ethnic and sex differences in the prevalence of clinically meaningful malocclusions that characterize approximately two-thirds of untreated US adults.