Bacteria of asymptomatic periradicular endodontic lesions identified by DNA-DNA hybridization

Possible inclusion of contaminant bacteria during surgery has been problema tic in studies of periradicular lesions of endodontic origin. Therefore, in this study, two different surgical techniques were compared. A second prob lem is that some difficult to cultivate species may not be detected using b acteriological methods. Molecular techniques may resolve this problem. DNA- DNA hybridization technology has the additional advantage that DNA is not a mplified. The purpose of this investigation was to determine if bacteria fr om periradicular endodontic lesions could be identified using DNA-DNA hybri dization. A full thickness intrasulcular mucoperiosteal (IS) flap (n=20) or a submarginal (SM) flap (n=16) was reflected in patients with asymptomatic apical periodontitis. DNA was extracted and incubated with 40 digoxigeninl abeled whole genomic probes. Bacterial DNA was detected in all 36 lesions. Seven probes were negative for all lesions. In patients with sinus tract co mmunication, in teeth lacking intact full coverage crowns, and in patients with a history of trauma, 4-13 probes provided positive signals. Seven prob es were positive in lesions obtained by the IS, but not the SM technique. T wo probes were in samples obtained with the SM technique, but not the IS. O nly Bacteroides forsythus and Actinomyces naeslundii genospecies 2 were pre sent in large numbers using either the IS or the SM technique. The SM flap technique, in combination with DNA-DNA hybridization, appeared to provide e xcellent data pertaining to periradicular bacteria. These results supported other studies that provide evidence of a bacterial presence and persistenc e in periradicular lesions.