THE USE OF A 16S RDNA DIRECTED PCR FOR THE DETECTION OF ENDODONTOPATHOGENIC BACTERIA

The study evaluates a 16S rDNA directed polymerase chain reaction (PCR ) to detect and differentiate bacteria in necrotic root canal samples. The examination focused on species that are fastidious concerning cul ture or are difficult to differentiate after culturing by biochemical methods. In the described PCR assay, a universal 16S rDNA directed for ward primer in combination with a highly specific reversed one was use d to amplify taxon specific gene fragments of 230 to 950 bp length. A similar PCR reaction using a universal 16S rDNA reversed primer was al so established to demonstrate bacteria in root canal specimens in gene ral. A first application of this method revealed the presence of Actin omycetales-species, Fusobacterium nucleatum, ''Streptococcus milleri,' ' and, presumably for the first time described in infected root canals , Bacteroides forsythus. The identity of amplificons was confirmed by generating sequence information and comparison to gene databanks.