Objective: This study was to longitudinally evaluate the change of prevalence of five periodontal putative pathogens in the subgingival plaque of artificial class III furcation defects at the three time-points, including before the establishment of furcation defects, before and 6 months after periodontal surgery.
Methods: Eighteen chronic infected class III FI defects were created at the mandibular first molars, second molars and second premolars of three adult male Macaca fascicularis. The samples of subgingival plaque were obtained from the subgingival area of furcation defects in buccal and lingual sites before the establishment of furcation defects, before and 6 months after periodontal surgery. 36 samples were obtained at one time-points. Five periodontal putative pathogens, including Porphyromonas gingivalis (Pg), Tannerella forsythensis (Tf), Treponema dinticola (Td), Actinobacillus actinomycetemcomitans (Aa) and Fusobacterium nucleatum (Fn), were detected with 16SrRNA based PCR.
Results: 1. The prevalence of Pg, Tf, Td and Fn was gradually increased, from 58.3% to 69.4% to 88.9%, 47,2% to 69.4% to 83.3%, 13.9% to 36.1% to 61.1% (P<0.01), and 69.4% to 91.7% to 91.7% (P<0.05), respectively during the experimental period. The prevalence of Fn was higher than Pg, Tf and Td. The prevalence of Aa was the lowest and no obvious difference among the three samplings(from 25.9% to 13.9% to 33.3%)was detected. 2. The prevalence of more than 3 species simultaneously detected was increased from 38.9% to 61.1% to 83.3% (P <0.01). The red complex (Pg + Tf + Td) was detected from 8.3% to 27.8% to 44.4% (P<0.01) at the different time point. 3. The combined detection frequency of red complex in the inflammatory sites (87.5%), which were histologically defined as inflammatory cells infiltrated in furcation area 6 months post-surgery, and the same sites pre-surgery (62.5%) was more than that in pre-creation of furcation defects (P<0.01). But there were no significant differences compared to that in non inflammatory area (60.0%, 40.0%), respectively.
Conclusion: The prevalence of periodontal pathogenic bacteria correlated with the severity of local inflammation. The increase of coexistent rate of red complex at the second and third sampling times suggests that the red complex play important role in the pathogenesis of periodontitis. Fn may be a resident bacteria in the subgingival plaque, play a bridge role on the biofilm formation and maturation. Aa may not be a major causative bacteria in the clinical periodontitis.