Association of Examination Rates with Children’s National Caries Indices in Finland

The objective was to assess the effect of examination rates on national caries indices of 5, 12 and 17-year-old children/adolescents in Finland. The data were gathered from patient records of the Public Dental Service (PDS) units (n=205, 73%) and from a national register. The data included PDS-specific total numbers of examined children/adolescents and means of decayed (d/D) teeth, dmft/DMFT-values and proportions of caries-free. For analytical purposes, the PDS-specific mean values weighted by the PDS population were calculated to imply the traditionally calculated figures. New PDS-specific examination-rate-adjusted mean values were calculated by using the predicted outcome values at 100% examination rates. The results showed that low examination rates were associated with slightly poorer oral health. The examination-rate-adjusted mean d/D- values indicated better oral health than the traditional indices. The adjustment slightly worsened oral health in proportions of caries-free, and had almost no effect on dmft/DMFT-value. Overall, the influence was modest. The high proportions of healthy children that are examined (against recommendation) and the relatively small number of those having extensive disease (frequently examined as recommended) probably mask the influence of examination rates on the indices in Finland. We conclude that in international comparisons, traditionally calculated indices seem to be sufficiently valid.