Ten-year follow-up of root filled teeth: a radiographic study of a Danish population.

AIM: To assess the long-term outcome of root filled teeth in a general adult population examined in 1997, 2003 and 2008. METHODOLOGY: The study provides longitudinal, observational information on endodontic status for 327 randomly selected individuals from a general Danish population receiving three consecutive full-mouth radiographic examinations. The association between root filling quality, periapical disease and the long-term outcome of the root filling and the root filled tooth was assessed using GEE methodology and tests for trend. RESULTS: Overall 13% of the root filled teeth had been extracted, 12% had received a revision of the root filling and 42% of root filled teeth present in 2008 had apical periodontitis (AP) after the 10-year follow-up period. The probability of persistent AP was higher if the root filling was either short or long (P = 0.001), if there were voids (P < 0.001), or if there were radiographic signs of overhang or open margin of the restoration (P = 0.01). Further, the probability of extraction was high if there were radiographic signs of overhang or open margin of the restoration (P = 0.008) and if the overall root filling quality was inadequate (test for trend, P = 0.03). CONCLUSIONS: The root filling quality primarily affected the risk of persistent AP and to a smaller extent the risk of extraction, whereas the quality of the coronal restoration primarily affected the risk of extraction and to a smaller extent the risk of persistent AP. If adjusted for AP present at the initial examination, the associations were less pronounced both in relation to extraction and persistence of AP.