Inequality in access to dental services in a market-based dental care system. A population study from Norway 1975-2018

Objective: To examine income-related inequalities in access to dental services from 1975 to 2018. In Norway, dental care services for adults are privately financed. This might lead to income-related inequalities in access to dental services. However, over the last decades Norwegians have experienced a rapid growth in income, including people with lower income. This may have led to improved access to dental services for these people. Therefore, inequalities in access to dental services may have become less over the last decades. Research design: This was a prospective study. Statistics Norway collected samples of cross-sectional health survey data for the following years: 1975, 1985, 1995, 2002, 2008, 2012 and 2018. For each sample, individuals 20 years and older were drawn randomly from the non-institutionalized adult population using a two-stage stratified cluster sample technique. Inequalities were measured using the concentration index. The dependent variable was use of dental services during the last year and the key independent variable was equalized household income. Results: The concentration index for inequalities in use of dental services according to income decreased from 0.10 (95% confidence interval = 0.09, 0.11) in 1975 to 0.04 (95% confidence interval = 0.03, 0.05) in 2018. The decrease was particularly large from 2002 to 2012. This was a period with a large growth in gross national income. Conclusion: People with a low income had a marked increase in their purchasing power from 1975 to 2018. This coincided with an increase in demand for dental care for this low-income group.