How an increase in income affects the use of dental care services among a low-income population: evidence from the Finnish basic income experiment.

BACKGROUND: Previous research has shown that the use of dental care services has a significant socioeconomic gradient. Lower income groups tend to use dental care services less, and they often have poorer dental health than higher income groups. The purpose of this study is to evaluate how an increase in income affects the use of dental care services among a low-income population. METHODS: The study examines the causal effect of increasing cash transfers on the use of dental care services by utilizing unique register-based data from a randomized field experiment conducted in Finland in 2017-2018. The Finnish basic income experiment introduced an exogenous increase in the income of persons who previously received basic unemployment benefits. Register-based data on the study population's use of public and private dental care services were collected both for the treatment group (N = 2,000) and the control group (N = 173,222) of the experiment over a five-year period 2015-2019: two years before, two years during, and one year after the experiment. The experiment's average treatment effect on the use of dental care services was estimated with OLS regressions. RESULTS: The Finnish basic income experiment had no detectable effect on the overall use of dental care services. However, it decreased the probability of visiting public dental care (-2.7% points, -4.7%, p =.017) and increased the average amount of out-of-pocket spending on private care (12.1 euros, 29.8%, p =.032). The results suggest that, even in a country with a universal public dental care coverage, changes in cash transfers do affect the dental care patterns of low-income populations.