AIM: To determine the prevalence of apical periodontitis and quality of root fillings in 35-year-old citizens of Oslo, Norway in 2003, and to compare the results with data from the same age cohort collected by repetitive cross-sectional studies in 1973, 1984 and 1993. METHODOLOGY: A random sample of 250 35-year-old Oslo inhabitants was drawn from The National Bureau of Statistics Recordings. Attendance rate was 64%. Root filled teeth and teeth with periapical pathology were detected from panoramic radiographs and additional periapical radiographs of affected teeth were processed. The preriapical status was evaluated by applying the periapical index system (PAI). Chi-square and Student's t-tests were used for the evaluation of differences between the groups. RESULTS: Twenty-three per cent of the individuals examined had root filled teeth and 16% had at least one tooth with apical periodontitis. Root filled teeth were associated with PAI values of 1 and 2 (health) in 57% of cases. Prevalence of root filled teeth and apical periodontitis remained unchanged during the past 10 years. An increase in the proportion of root filled teeth with apical periodontitis from 18% in 1973 to 43% in 2003 was observed. CONCLUSIONS: Despite continuous improvement in dental health (reduced DMF-values) compared with the previous Oslo studies; there was no improvement in endodontic status from 1993 to 2003.
