Identification of periodontopathic bacteria DNA from periodontitis-involved gingival tissue using a PCR method

The purpose of this study was to determine the presence of periodontopathic bacteria DNA in the granulation tissue of periodontally involved gingival tissue. Forty periodontitis patients were examined. Subgingival plaque and saliva samples were collected from the patients before surgery. Then, granulation tissue was also collected during surgery. Another 20 patients, who had more than 4 mm in probing pocket depth, were also examined as a control. They received only initial treatment without periodontal surgery. Plaque and saliva samples were also collected from them. Seven periodontopathic bacteria, Porphyromonas gingivalis, Bacteroides forsythus, Toreponema denticola, Campylobacter rectus, Actinobacillus actinomycetemcomitans, Prevotella intermedia, and Prevotella nigrescens, were detected by a PCR method from these samples of all patients. As clinical parameters, probing pocket depth, clinical attachment level, and bleeding on probing were recorded. One year after surgery, sampling of subgingival plaque and saliva, and measurement of clinical parameters were performed on the patients. The DNA of periodontopathic bacteria was detected in the granulation tissue of 29 out of 40 patients. P. gingivalis, B. forsythus, T. denticola, C. rectus, A. actinomycetemcomitans, P. intermedia and P. nigrescens were detected in 23, 11, 12, 9, 3, 2 and 1 subject(s) respectively. The sites with undetectable level of any periodontal pathogens at one year after surgery showed a clinical attachment gain of 2.44 mm, while those that showed detectable pathogen levels had only a 0.77 mm gain. Our results indicated that the removal of granulation tissue contributed to eliminating periodontal pathogens and to avoiding re-infection by those bacteria. Complete eradication of periodontopathic bacteria would be necessary for successful periodontal treatment.