Educational inequalities in access to fixed prosthodontic treatment in Norway. Causal effects using the introduction of a school reform as an instrumental variable

Abstract

Objectives

Equality in access to dental services, independent of level of education, is an important aim of Scandinavian welfare policy. In Norway, this policy is the main justification for a dental public subsidy scheme for adults. An important part of the subsidy scheme is to cover the cost of fixed prosthodontic treatment, including implant-based crowns and bridges for premolars, canines and incisors. A stated policy goal is to secure equal access to everybody in need of these services, independent of their level of education. The aim of this study was to estimate the causal effect of education on the probability of receiving fixed prosthodontic treatment in the adult Norwegian population. Methods

During the period 1960–1972, all municipalities in Norway were required to increase the number of compulsory years of education from seven to nine years. We used this education reform as the instrumental variable to create exogenous variation in the individual's number of years of education. The education data were combined with data from the Norwegian Health Economics Administration, which contained our outcome variable. Our sample included individuals with 9 years education or less. Altogether 113 237 individuals were included in the study. Results

For men, the first stage regression coefficient was 0.87 (confidence interval: 0.82–0.92). This means that the reform resulted in 0.87 additional years of education. For men, the probability of receiving fixed prosthodontic treatment increased by 0.67 percentage points per additional year of schooling. For women, the first stage regression coefficient was 0.84 (confidence interval: 0.79–0.88). The second stage regression coefficient was small (= 0.0022) and not statistically significant at a conventional level. Conclusion

From a welfare policy point of view, for men, the subsidy scheme has not succeeded to redistribute resources so that dental services are accessible independent of their social status.