Prevalence of apical periodontitis in root-canal-filled teeth - a cross-sectional study.

OBJECTIVE: The aim of this cross-sectional study was to assess the root canal filling quality and the frequency of apical periodontitis (AP) in root-canal-filled teeth in a randomly selected adult non-patient population in Sweden. MATERIALS AND METHODS: In 2023, 295 root-canal-filled teeth were identified in 126 adults in a cross-sectional study in Jönköping, Sweden. Periapical radiographs were assessed by two calibrated observers. The periapical status was scored according to the periapical index (PAI) and then dichotomized as either healthy (PAI 1-2) or diseased (PAI 3-5). The root canal filling quality was deemed as adequate/inadequate. An adequate root canal filling was considered to end 0.5-2 mm from the radiographic apex and to have no radiolucent voids. RESULTS: Adequate root canal fillings were seen in 89 (30.2%) of the teeth. AP was present in 94 (31.9%) of the teeth, and of these, 72 (76.6%) had an inadequate root canal filling. Of the 122 root-canal-filled molars, 101 (82.8%) had inadequate root canal filling and 57 (46.7%) had AP. CONCLUSION: A large proportion of root-canal-filled teeth have inadequate root canal filling quality and AP, especially in molars. Both contributing factors and strategies for improvement require further study.