Effect of radiation dose on the prevalence of apical periodontitis--a dosimetric analysis.

Objectives: The objective of this study is to analyse the effect of the radiation dose of oral radiotherapy for cancer on the presence of apical periodontitis in patients without dental pre-screening or specific preventive measures.

Materials And Methods: All selected patients had been diagnosed with cancer in the head and neck region and presented in the dental clinic post radiotherapy with side effects (mainly radiation caries). The panoramic radiographs of these patients were examined for several parameters, including tooth decay and apical periodontitis. The total radiation dose per tooth was determined.

Results: A total of 36 patient files were included, which accounted for 628 teeth to be scored. Tooth decay was present in 88.2% of teeth. Radiographic signs of apical periodontitis were found in 9.1% of the teeth. Teeth with apical periodontitis had significantly more caries present. The radiation dose was significantly higher for teeth with apical periodontitis (37.2 vs. 24.9 Gy). Binary logistic regression found the radiation dose to be the only explanatory variable in the presence of apical periodontitis.

Conclusions: This study found that in zones with higher radiation dose, inflammation of the jawbone due to bacterial infection of the root canal is more likely to develop. This is probably due to bone changes post radiotherapy.

Clinical Relevance: An increase of this prevalance of apical periodontitis in irradiated bone found in this study needs to be taken into account in the dental evaluation before the start of radiotherapy.