Disparities in Dental Use and Untreated Caries Prevalence by Income.

INTRODUCTION: Untreated dental caries (UC), although preventable, is the most prevalent disease in the United States. UC diminishes quality of life and lowers productivity for millions of Americans and is notably higher among lower-income compared to higher-income persons. OBJECTIVE: This study examines changes in disparities by income in past-year dental use (DU) and UC in 4 life stages (2-5, 6-19, 20-64, and >/=65 y) between 1999-2004 and 2011-2016. We also examined changes in dental safety net policies during this time. METHODS: We obtained data on dependent variables, UC and DU, from cross-sectional, nationally representative surveys for 1999-2004 and 2011-2016. We used multivariable regression models with 3 main-effect explanatory variables: income (<200% or >/=200% federal poverty level), life stage, and survey period (1999-2004 or 2011-2016) and sociodemographic variables. We included 2-way interaction terms among main-effect variables to test whether disparities had changed over time in each life stage and a 3-way term to test changes in disparities differed across life stages. RESULTS: Model-adjusted disparities in DU decreased for both preschool-age and school-age children, and disparities in UC decreased for school-age children. Changes in DU and UC disparities were not detectable for working-age adults and increased for retirement-age adults. Changes in DU and UC among preschool and school-age children were not significantly different from one another and were significantly different from changes among retirement-age adults. Compared to working-age adults, changes in disparities for DU and UC were significantly different for school-age children, and changes in DU were significantly different for preschool-age children. Between surveys, the dental safety net was expanded for youth but remained largely unchanged for adults. CONCLUSIONS: Expanding the dental safety net for youth could have contributed to increased access to dental care among children relative to adults and contributed to the decrease in disparities in DU and UC among youth. KNOWLEDGE TRANSFER STATEMENT: Between 1999-2004 and 2011-2016, the dental safety net was expanded for youth but remained largely unchanged for adults. Using national survey data to compare changes in disparities in past-year dental use and untreated dental caries by income between adults and youth sheds light on the potential impact of expanding the dental safety net.