Caries diagnosis: agreement between WHO and ICDAS II criteria in epidemiological surveys

The aim of this study was to ascertain the equivalence between WHO caries diagnosis criteria and the ICDAS II caries classification scale for comparisons in epidemiological studies.

Two intraoral examinations, one using the ICDAS II caries codes and the other the WHO caries assessment method, were performed in a random sample of 101 children (29 aged 5-6 years, 32 aged 12 and 40 aged 15). Both examinations were performed not more than one month apart by two calibrated examiners (one for ICDAS II criteria, Kappa=0.86, and the other for WHO criteria, Kappa=0.91). The DMFT/dft, DMFS/dfs and caries prevalence (DMFT or dfs>0) indices were obtained in accordance with WHO assessment criteria and by applying 5 cut-off points on the ICDAS II scale. The differences between means were analysed with the Wilcoxon test and those between proportions with the McNemar test. Agreement was determined by the intraclass correlation index and the Kappa statistic.

The least differences between the WHO and ICDAS 11 criteria were found at cut-off point 3 (ICDAS 11 codes 3 to 6). The greatest agreement was found at the same cut-off point.

While the equivalence between both methods used in epidemiological studies does not appear to be clear, possible errors could be reduced by locating this equivalence at cut-off point 3 and not at cut-off point 4.