Risk factors for developing apical periodontitis in a general population

To identify and describe individual and tooth-specific factors associated with the incidence or the persistence of apical periodontitis (AP) in a general population.

In 1997, 616 randomly selected individuals had a full-mouth radiographic survey. In 2003, 77% of the participants returned for a new full-mouth radiographic examination. All teeth were assessed individually and data recorded for caries, marginal bone level, and tooth restorations. Multiple logistic regression analyses were performed to identify predictors of AP in the individual. Conditional logistic regression analyses were used to identify risk factors for development of AP in a tooth. Independent variables included a number of individual and tooth-specific variables.

Root fillings, coronal restorations, primary carious lesions, and reduced marginal bone level were associated with the incidence of AP in the individual. In teeth, the quality and presence of a coronal restoration was associated with the incidence of AP, and presence of a root filling also increased the risk of developing AP. Furthermore, an increased risk of developing AP was seen in relation to primary carious lesions, reduced marginal bone level, and molar teeth. The quality of the root filling was not associated with the incidence of AP, but the results suggest an association between the quality of the root filling and the healing of AP.

Results from the present study demonstrate that it is important to provide high quality dental restorations to minimize the risk of pulpal infection. The clinical focus, in relation to the incidence of AP, should be on improving the quality of the coronal restoration. The quality of a root filling was not associated with the incidence of AP, but may be of importance in relation to healing of AP.