Towards an understanding of the structural determinants of oral health inequalities: A comparative analysis between Canada and the United States

• Highlights changes and contributors to oral health inequalities in Canada and the U.S. since 1970.
• Provides a comparative framework for analysing income-related oral health inequalities.
• Hypotheses-generating findings on contributors to income-related oral health inequalities.

ObjectiveTo compare the magnitude of, and contributors to, income-related inequalities in oral health outcomes within and between Canada and the United States over time.MethodsThe concentration index was used to estimate income-related inequalities in three oral health outcomes from the Nutrition Canada National Survey 1970–1972, Canadian Health Measures Survey 2007–2009, Health and Nutrition Examination Survey I 1971–1974, and National Health and Nutrition Examination Survey 2007–2008. Concentration indices were decomposed to determine the contribution of demographic and socioeconomic factors to oral health inequalities.ResultsOur estimates show that over time in both countries, inequalities in decayed teeth and edentulism were concentrated among the poor and inequalities in filled teeth were concentrated among the rich. Over time, inequalities in decayed teeth increased and decreased for measures of filled teeth and edentulism in both countries. Inequalities were higher in the United States compared to Canada for filled and decayed teeth outcomes. Socioeconomic characteristics (education, income) contributed greater to inequalities than demographic characteristics (age, sex). As well, income contributed more to inequalities in recent surveys in both Canada and the United States.ConclusionsInequalities in oral health have persisted over the past 35 years in Canada and the United States, and are associated with age, sex, education, and income and have varied over time.