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

Aim The purpose of this study was to examine the presence of bacteria on th e apical root surfaces of untreated teeth associated with chronic periradic ular lesions. Methodology Twenty-seven extracted teeth with extensive carious lesions, ra diolucent lesions of varying sizes and attached periradicular lesions after extraction, were selected for study. Following fixation. lesions were remo ved 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 microscop e, 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 s pecimen. Beyond the apical foramen, other bacterial morphological types wer e recognized, including coaggregations of cocci and filaments, characterizi ng a fully developed 'corn cob'. Conclusions Extraradicular bacteria were observed in one tooth out of 27 (4 % of the cases).