Income, income inequality, dental caries and dental care levels: an ecological study in rich countries.

Research has shown that beyond a certain level of absolute income, there is a weak relationship between income and population health. On the other hand, relative income or income inequality is more strongly related to health than absolute income in rich countries. The objective of this study was to assess the relationships of income and income inequality with dental caries and dental care levels in 35- to 44-year-old adults among rich countries. Income was assessed by gross domestic product and gross national income, income inequality by Gini coefficient and the ratio between the income of the richest and poorest 20% of the population, dental caries by DMFT and dental care levels by the care, restorative and treatment indices. Pearson and partial correlation were used to examine the relationships between income, income inequality, caries experience and dental care. Income measures were not related to either dental caries or dental care levels. However, income inequality measures were inversely and significantly related to number of filled teeth, DMFT, care index and restorative index, but not to number of decayed or missing teeth. It is concluded that DMFT scores were higher in more equal countries and may be explained by greater levels of restorative care in those countries. (c) 2009 S. Karger AG, Basel.