Health insurance reduces the economic burden of diseases and enhances access to medical services. This study compared, among social classes, the utilization of preventive dental service before and after health insurance covered dental scaling. We analyzed time-series secondary data for 3 175 584 participants from 253 survey areas nationwide in the Community Health Survey (2009-2014) in Korea. The weighted proportion of participants who underwent dental scaling was defined as the scaling rate. Data regarding demographic and socioeconomic characteristics were collected. Scaling rates continuously increased over the 6-year period, particularly in 2014. College graduates had significantly higher scaling rates. Monthly income and scaling rate were positively related. Differences by education decreased over time. Differences by income were particularly high between 2012 and 2014. For women, the temporal rate was 2 times higher for professionals than for the unemployed. Despite increased dental scaling rates since the health coverage change in 2013, socioeconomic differences persist.

Background: In 2009, the South Korean government expanded universal health insurance to include oral health services. In the present study, we sought to examine whether improved access resulted in a reduction in income-based self-reported oral health inequalities. Methods: We analyzed repeated cross-sectional data from the Korea National Health and Nutrition Examination Survey (KNHANES) waves IV through VI (2007–2015). We analyzed self-reported oral health status among 68,431subjects. Changes in oral health inequalities across four income levels (low, middle-low, middle-high, and high) were assessed with the Slope Index of Inequality (SII) and the Relative Index of Inequality (RII). Results: The average oral health status of children and adolescents improved the most over the observation period. The absolute magnitude of oral health inequalities (measured by the SII) improved for most groups, with the notable exception of young male adults. By contrast, the ratio of poor oral health between high- and low-income groups (measured by the RII) changed little over time, indicating that relative inequalities remained resistant to change. Conclusions: The expansion of dental health insurance may not be sufficient to move the needle on self-reported oral health inequalities among adults.

Background: In 2012, the Korean government expanded dental insurance for the elderly to promote improved access to dental care. We examined the causal effect of this policy on dental care needs, focusing on low-income older adults.Methods: We compared data before and after policy implementation using double difference (DD) and triple difference (DDD) analyses. We used the nationally representative data from the Korea National Health and Nutrition Examination Survey from 2010 and 2016–2018. Individuals aged ≥65 years were included in the treatment group, and individuals aged <65 years were included in the control group.Results: Dental insurance expansion was associated with a paradoxical increase in perceived unmet dental needs among elderly individuals (8.8 percentage points increase, 95% CI: 4.7 to 13.0). However, there were improvements in dental prosthetics outcomes (denture wearing [4.0 percentage points, 95% CI: 0.2 to 7.9] and dental implants [5.0 percentage points, 95% CI: 2.1 to 7.9]; P < 0.01). Upon analyzing low-income elderly individuals by using DDD analysis, we found that the insurance expansion led to a 21.6% lower increase in unmet dental needs among low-income adults, compared to high-income adults (95% CI: -35.0 to -8.5; P < 0.01).Conclusions: Dental insurance expansion in South Korea resulted in improvements in access to dental prosthetic services overall. It also led to a lower increase in unmet dental needs among low-income older adults, compared to high-income adults.