Evaluation of social inequality of use of dental services in Norway.

Abstract

It is tempting to assume that the increase in use-rates in Norway throughout the 1970's reflects a decrease in social inequality concerning use of dental services. In order to assess whether or not equalization has been achieved from 1973 to 1983, the application of a conservative and a radical standard led to different conclusions about equalization. Therefore, a formal model containing explicit assumptions was constructed and used to test the null hypothesis of no significant change in social inequality concerning regular use of dental services as well as no significant change in use-rates from 1973 to 1983. The model corrects for the ceiling effect as the proportion of regular dental visitors from a social status group increases, by assuming that the dental visiting potential is normally distributed within each social status group. The empirical basis was formed by nationwide interview surveys in 1973 (n = 1630) and in 1983 (n = 1410). Level of income was selected as indicator of social status and grouped into seven categories. Regular visitor rates for each income group were transformed to standard normal deviates (z-scores) and regressed upon level of income separately for 1973 and 1983. There was a net improvement of proportions of regular dental visitors from 1973 to 1983 as measured by a significant decrease of the intercept, but no equalization between social status groups as measured by no significant change of the slope.