Is apical periodontitis in root filled teeth associated with the type of restoration?

OBJECTIVE: To study the association between type of restoration and apical periodontitis (AP) in root filled teeth. MATERIALS AND METHODS: The present study used data from surveys conducted in 1983, 1993 and 2003. In 1983, 130 randomly selected subjects aged 3-80 years in the city of Jonkoping, Sweden, were invited for a clinical and radiological examination. The study was repeated in 1993 and 2003. New participants were, thus, recruited with the same sampling criteria and sample size in the same geographical area in 1993 and 2003, respectively. In the present study, only dentate individuals aged 20-70 years with >/=1 root filled tooth were included, yielding a sample of 788 subjects with 2634 root filled teeth. Apical periodontitis on the tooth level was the dependent variable. Periapical status was assessed according to Periapical Index (PAI). Independent variables were root filling quality, recurrent caries, type of restoration, number of teeth with apical periodontitis, age and gender. Root fillings appearing homogenous and ending within 2 mm from radiographic apex were regarded as adequate, otherwise inadequate. All radiographs were re-studied by one observer regarding periapical status and root filling quality. Risk was analyzed by means of a GEE model. RESULTS: Type of restoration, root filling quality, number of teeth with apical periodontitis within the individual and age were found to be predictors of AP in root filled teeth. Presence of recurrent caries and gender were not found to be associated with AP. CONCLUSIONS: According to the present study, root filling quality and type of restoration may be predictive of AP in root filled teeth.