Changing Inequalities in the Distribution of Caries Associated with Improving Child Oral Health in Australia

Objectives: This study aimed to document the changing distribution of and inequalities in dental caries in Australian children across the 25-year period from 1977 to 2002. Methods: Oral health data were obtained from Australia's national Child Dental Health Survey. Measures of caries distribution included the Significant Caries Index and the proportions of children with high caries experience [decayed, missing and filled teeth (DMFT) >= 4], while inequality was assessed by using Gini coefficients calculated from Lorenz curves. Changes in caries distribution were compared with changes in child dmft/DMFT. Results: While appreciable reductions occurred in child caries experience, in terms of both mean dmft/DMFT and for those children with the poorest oral health, inequalities in the distribution of caries experience increased across the 25-year period. Inequalities in the distribution of decayed and filled teeth differed for the deciduous and permanent dentition and, in the permanent dentition, became increasingly similar in the 1990s. Conclusions: Increasing inequalities in child dental caries in Australia must be interpreted in the context of declines in both mean caries experience and in the caries experience of those children with the poorest oral health. The Gini coefficient documents that the majority of the caries experience is increasingly being confined to a smaller percentage of the child population; however, this is a consequence of population-wide child oral health improvements.