Examining changes in income-related oral health inequality in Canada: a population-level perspective

Introduction: Monitoring trends in oral health outcomes is key to identifying population needs and informing policy for improvements in oral health of Canadians. At present, effort to examine income-related inequalities in oral health and their changes over time has been minimal in Canada. Our objectives were to examine and compare income-related inequalities in decayed teeth in Canada between 1970 and 2000s. Methods: A secondary data analysis using the Nutrition Canada National Survey 1970-1972 and Canadian Health Measures Survey 2007-2009 was performed in order to examine individual- and population-level income-related inequalities in oral health. Income quintiles and concentration indices for the presence of one or more decayed teeth were derived using indirect standardization and multivariate logistic regression. Results: Results highlight that income-gradients in oral health have persisted over time, with lower reductions in decayed teeth in lower income quintiles than higher quintiles. Higher concentration indices were exhibited in more recent surveys suggesting an increase in income-related inequality in decayed teeth over time. Conclusion: Our findings provide a benchmark for measuring changes to income-related inequalities in oral health in the Canadian population and reveal that inequalities in untreated dental disease have persisted despite overall reductions in caries rates over time