Apical Periodontitis in Orally Irradiated Patients: an Analysis

Objectives: No study has yet investigated the prevalence and influencing factors of apical periodontitis (AP) in head- and neck irradiated patients. The present study investigates oral parameters and the radiation dose on individual teeth and their effect on apical periodontitis. Methods: 36 patients (33 males, 3 females) were selected for this study. They all needed post radiotherapy dental care. Panoramic radiograph were obtained and analysed by two investigators on the following parameters: apical periodontitis, restorations and caries. Subsequently, a dosimetric analysis per tooth was performed. Results: The average age was 52.19 (+/-8.9) years. The average time between the examination and the end of radiotherapy was 21.42 (+/-15.3) months. 628 teeth were scored. AP was present on 9.1% of teeth and caries on 88.2% of teeth. Teeth with AP had a statistically significantly higher caries rate (p<0.05). The quality of coronal restorations had no significant effect on the prevalence of AP. The average radiation dose on all teeth was 26 (+/-31.6) Gy. The radiation dose was significantly different between teeth with and without AP (p<0.01) and teeth with and without caries (p<0.05). A binary logistic regression was performed to determine the explanatory variables of AP. The radiation dose was the only variable that significantly influenced the periapical condition (p<0.01, Odds: 1.003). Life Table Analysis was performed to study the effect of the radiation dose in relation to the time since radiotherapy. Teeth that were not in the field of radiation showed a statistically significant higher survival rate (appearance of AP) than teeth that were in the radiation field (Wilcoxon-Gehan statistic = 6.077, p<0.05). Conclusion: The radiation dose per tooth was the only parameter that had a significant influence on the presence of AP, according to the binary logistic regression. The radiation dose also has a significant influence on the caries rate.