Proximal caries prevalence in 19-year-olds living in Sweden. A radiographic study in four counties.

A random sample of all 19-year-olds in four counties in the middle of Sweden in 1994 constituted the group studied. The material consisted of posterior bitewing radiographs from 511 19-year-old patients. The purpose was to study the prevalence and distribution of initial and manifest caries. It was found that on the manifest caries level 56% of the subjects were 'free from caries', in good correspondence with the official epidemiological data from the Swedish National Board of Health and Welfare, but only 27% when initial caries was added. Initial caries lesions constituted 90% of all lesions. The distribution of caries was highly skewed on the manifest caries level whereas initial caries had a broader distribution. Thus, on the surface level 75% of the individuals had 16% of all manifest caries and restorations, and 33% of all initial caries. A high correlation was found between initial and manifest caries, besides increasing with the number of initial lesions. Thus, only 2.5% of individuals without initial caries had manifest caries, compared to 54% of individuals with more than eight affected surfaces. A correlation was also found between the prevalence of manifest caries and restoration. The prevalence of initial caries and its obvious significance for further caries development should be a reason for finding new strategies in caries prevention on a population basis.