Aims and objectives: To assess the risk factors of apical periodontitis (AP) in a Nigerian sub-urban adult population and to compare the findings with those previously reported for various population groups.

Materials and methods: The study was based on a full mouth radiographic survey of 285 patients. Patients' age ranged from 18-60 years. All teeth were assessed individually and data recorded for caries, fractured / cracked teeth, root fillings, and tooth restorations. The gender, smoking habit, and frequency of dental visit were also recorded. Multiple logistic regression analyses were performed to identify predictors of AP in the individual.

Results: The prevalence of AP was 74.4%. The average number of teeth with AP per patient was 2.8 (range 1-5). AP was found to be more prevalent among people 40- 49 years old (87.2%). Primary carious lesions, fractured / cracked teeth, root fillings and coronal fillings were associated with the incidence of AP in the individual. Fractured teeth had a higher risk of developing AP than carious teeth. The presence of root fillings and coronal restorations were also associated with the development of AP. Smoking (OR=3.82; CI=2.17-6.75) and irregular dental visit (OR=6.73; CI=3.75-12.06) were statistically significant risk factors for developing AP. Gender was not a risk factor for AP (OR=0.86; CI=0.50-1.46).

Conclusion: The prevalence of AP among adult Nigerians is slightly higher than reported figures for many Western societies. Fractured/cracked teeth had a higher risk of developing AP than carious teeth; hence patients with fractured / cracked teeth should seek treatment early to prevent the development of AP.