Terminal restriction fragment length polymorphism analysis of the microflora in necrotic teeth of patients irradiated in the head and neck region

This study evaluated the microflora in root canals of necrotic teeth after radiotherapy of the head and neck region. The microbial composition of samples taken from necrotic root canals in patients treated with irradiation of the head and neck (group A, n = 13) and in healthy controls (group B, n = 11) was analyzed by terminal restriction fragment-length polymorphism (T-RFLP) analysis. A total of 50 different terminal restriction fragment lengths (T-RFs) (each representing one or more bacterial species) were detected in the T-RFLP profiles, 44 in group A and 28 in group B. A mean of 13.2 T-RFs per sample were detected in group A and 6.6 T-RFs were present per sample for group B (p < 0.05). Twenty-two different T-RFs (mainly subspecies of Lactobacillus spp., Capnocytophaga spp., and Actinomyces spp.) found in group A were not found in group B. In conclusion, the diversity of root canal microflora increases significantly after head-neck radiotherapy.