In the oldest elderly, an increase in the number of remaining teeth may increase oral infection foci. The aim of this follow-up study was to examine the radiologically detected oral health condition of a group of home-living elderly in Helsinki at 5-year intervals. The population of this study comprised 103 home-living elderly people, all participants of the population-based Helsinki Aging Study. Panoramic radiography supplemented by intraoral radiographs was performed on all these participants at the Institute of Dentistry, University of Helsinki, in 1990-1991. Follow-up radiographic examination was completed in 1995-1996. Mean number of teeth decreased during the follow-up period from 13.2 +/- 9.0 to 12.5 +/- 9.2 (P= 0.0001). Mean number of teeth with periapical lesions decreased in men from 1.3 +/- 1.4 to 0.6 +/- 0.9 (P = 0.007), but no differences in number of teeth with periapical findings were observed in women. There were relatively few changes in the subjects' radiographic periodontal findings. However, fewer teeth with vertical bone pockets >1-3 mm deep were found in the follow-up study than 5 years earlier (0.6 +/- 1.2 vs 1.1 +/- 1.8; P= 0.0008). In both the baseline and the follow-up studies the radiographic findings occurred in the subjects who had retained more natural teeth. In the follow-up study, 68% of the subjects had radiographically detected signs of chronic oral infection foci. It may be concluded that radiographically detected oral health parameters remain relatively unchanged, but treatment need is higher among those who have successfully retained their natural dentition into old age.