Epidemiological investigations from Scandinavia have documented high prevalence of apical periodontitis and inferior quality and results of endodontic treatment performed in general practice. The present investigation is part of a 20-year follow-up study on oral health in 35-year-old Oslo citizens focusing on endodontic conditions. The results indicate reduced prevalence of apical periodontitis and statistically significant improvement in endodontic status compared with results from a similar study performed in 1984.