Methods: Panoramic radiographs of 45 patients lacking dental treatment during and after radiotherapy, taken averagely 23.2 months after radiotherapy were examined for periapical and coronal condition and endodontic treatment. The findings were compared with data (between parentheses) of a previous study in a Belgian general population (De Moor et al. 2000).
Results: A total of 765 teeth were scored, 6.4% (6.8%) were endodontically treated. Apical periodontitis was found in 7.6% (6.6%) of all teeth and in 12.2% (40.4%) of the endodontically treated teeth. 53.3% (63.1%) of the subjects had one or more teeth with apical periodontitis. 47.9% (56.7%) of the root fillings were filled to an adequate length. Of all teeth, 86.3% (13.9%) were decayed, with radiographic evidence of caries extending into the pulpal space in the majority of cases.
Conclusion: The high incidence and severe degree of caries inevitably result in ingress of saliva and micro organisms in the root canal with diffusion into the periradicular tissues through the root apices and foramina. This would suggest a higher incidence of apical periodontitis than in the general population. No difference was found in the prevalence of apical periodontitis between the two populations. This may be due to bacterial shifts in the oral cavity and root canal, resulting in a less pathogenic flora. Another explanation could be the reduced vitality of irradiated bone caused by irradiation. The radiation damages the cellular component of the bone as well as the vascularisation.