Bacteria on the apical root surfaces of untreated teeth with periradicular lesions: a scanning electron microscopy study

Aim The purpose of this study was to examine the presence of bacteria on the apical root surfaces of untreated teeth associated with chronic periradicular lesions. Methodology Twenty-seven extracted teeth with extensive carious lesions, radiolucent lesions of varying sizes and attached periradicular lesions after extraction, were selected for study. Following fixation. lesions were removed and the apical 5-mm portion of each root was sectioned, Root tips were dehydrated, sputter-coated with gold, and then examined for the occurrence of bacteria on the apical root surfaces using a scanning electron microscope, Results Bacterial calls were usually observed close to the apical foramen, but restricted to the root canal, Morphologically. these bacteria consisted of cocci and rods, A dense bacterial aggregate composed mainly of rods was observed within the root canal and surrounding the apical foramen of one specimen. Beyond the apical foramen, other bacterial morphological types were recognized, including coaggregations of cocci and filaments, characterizing a fully developed 'corn cob'. Conclusions Extraradicular bacteria were observed in one tooth out of 27 (4% of the cases).