Income-based inequalities in dental service utilization: A multiple mediation analysis

With elimination of the financial burden of dental services, one can expect an increase in utilization of dental services. This study aimed to investigate the effective mechanisms of financial barriers to the utilization of dental services in an Australian adult population. South Australian survey data from the Dental Care and Oral Health Study (2015) were analysed. Following the flexible mediation approach, the direct effect of income and indirect effect of income through mediators (insurance, concession card and service sector) on the outcomes (visit avoidance and treatment prevention due to the cost) were calculated. Findings showed that around half of the low-income people and one-third of the high-income South Australians experienced a financial burden on receiving a dental visit or service. The indirect effect of income on both outcomes of financial burden was negligible, while the direct effect was significant. By changing the potential outcome distribution to their counterfactual exposure distribution and if the mediators are drawn from their counterfactual exposure (lower/higher income) distribution, the odds of visit avoidance and treatment prevention due to the cost were almost twice (Odds Ratio: 2.13, 95% CI 1.72-2.60) and 98% (Odds Ratio: 1.98, 95% CI 1.67-2.35) than in the lower-income individuals, respectively. It can be concluded that the level of household income, directly and regardless of insurance status, concession card ownership and whether the service sector was public or private, affected the financial burden on utilization of dental services.