Objective To describe trends in income disparities in dental caries among U.S. children and adolescents during two decades of fluctuating economic growth. Methods Data were from National Health and Nutrition Examination Surveys conducted in 1988-1994, 1999-2004, and 2011-2014. The number of tooth surfaces with dental caries experience per child was computed for three age groups: 2-5, 6-11, and 12-17 years. Absolute and relative measures of inequality compared caries experience in families below the poverty level with families where income was at least three times the poverty threshold. Results Conspicuous, inverse income gradients in dental caries were observed at each time period and in each age group. However, there was no consistent trend or statistically significant change in the degree of inequality between survey periods. Conclusions Persisting income disparities in dental caries among U.S. children and adolescents challenge public health dentistry to redouble efforts to redress the inequity.