A rapid DNA probe method for detection of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans

The objective of the present study was to develop a rapid DNA probe method for the microbiological detection of periodontitis that can be used in dental clinics. By using the DNA probe, we also investigated the correlation between the occurrence of putative periodontopathic bacteria and clinical parameters.

This rapid DNA probe method minimizes the use of a water bath for ordinary hybridization and washing in order to shorten the total reaction time. The detection process could be completed within 2 hours. In order to evaluate the clinical application of the DNA probe, subgingival plaque samples were taken from patients with periodontitis before initial therapy. After the therapy, the patients were microbiologically and clinically evaluated.

When the DNA probe method was compared with the culture method, the agreement was 88% for Porphyromonas gingivalis and 67% for Actinobacillus actinomycetemcomitans. A statistically significant association was found between the detection of P. gingivalis and probing depth, bleeding on probing (chi2 test: P <0.001, P <0.05). A significant association was also shown between the detection of A. actinomycetemcomitans and probing depth in patients aged 35 or older (chi2 test: P <0.001). The detection rate of A. actinomycetemcomitans was highest in teenagers. At shallow periodontal pocket sites (PD < or =3 mm) in teenagers, no P. gingivalis was found, while 22% of the sites harbored A. actinomycetemcomitans. After the therapy, the frequency of detection of P. gingivalis decreased significantly only in the clinically improved sites (chi2 test: P <0.001).

The rapid DNA probe method appears promising as an efficient tool for rapid clinical detection of periodontopathic bacteria.