Associations Between 5 Subgingival Putative Periodontal Pathogens And The Clinical Parameters Following SRP

Purposes: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Bacteroides forsythus, Prevotella intermedia and Treponema denticola are known as the most important subgingival putative periodontal pathogens ,which are associated with chronic periodontitis tightly. Scaling and root planing is a main therapeutic procedure, but patients response to this therapy differently., The Change of the subgingival microorganisms is an important factor influening the treatment outcome before and after therapy. The purposes of this study was to evaluate the associations between the changes of the five microorganisms and the clinical parameters following SRP, and determine the useful microbial indicators for prediction and assessment of the treatment outcome following SRP by investigating the changes of clinical parameters including probing pocket depths (PPD), clinical attachment loss (CAL) and bleeding of probing (BOP) and the five microorganisms in the Chinese patients with moderate or severe chronic periodontitis before and after SRP. Methods: Twenty patients (12 female and 8 male) with moderate or severechronic peridontitis volunteered in this study. Two of the deepest pockets of each patient were selected as the study sites. Clinical parameters including PPD> CAU BOPwere monitored and subgingival plaque samples were taken prior to therapy and after 3 months. All subjects received oral hygiene and full mouth SRP. semi-quantification of A. actinomycetemcomitans , P. gingivaliSf B. forsythus, P. intermedia and T. denticola were determined by polymerase chain reaction (PCR) and reverse hybridization assay. Results: P. gingivalisingivalis, B. forsythusorsythus, P. intermedia and T. denticola were detected in a high proportion at baseline (corresponding values were 97.5%, 95%, 100%^ 97.5%) . But the proportion of A. actinomycetemcomitans was low (20%). The levels of P. gingivalisingivalis, B. forsythus, and T. denticola were significantly reduced after SRP (P<0.05 / P<0.001), however the level of A. actinomycetemcomitans increased lightly (P> 0.05) without statistical significance.The levels of P. gingivalis, B. forsythusorsythus and T. denticola of the sites with reduction of =2mm PPD decreased markly (P<0.05). After therapy, the mean PPD reduction (1.16 ± 0.83mm) of the sites at which the level of P. gingivalis increased or didn't change was less than the P. gingivalis-decieased sites (2.00±1.22mm) significantly (P<0.05) . The B. forsythus-decreased sites got more mean PPD reduction (2.04±1.17mm) and % sites of BOP improvement (60.0%) than the sites which the level of B. forsythus was increased or kept steadyly (26.7%) after therapy (P<0.05). The level of B. forsythus at the responding sites was less than the no responding sites significantly (P<0.05) . The level off! intermedia was significantly higher in the no responding sites (reduction of PPD <2mm) than theresponding sites (reduction of PPD =2mm).Conclusions: The % of sites of P. gingivalis, B. forsythus, P. intermedia and T. denticola were high in the subjects, while that of A.actinomycetemcomitans was low. No apparent association exists between the changes of A.actinomycetemcomitans and clinical parameters in this study. The high level of P. intermedia prior therapy or the high level of B. forsythus after therapy is related to the ineffective treatment. The control of the levels of P. gingivalis, B. forsythus and T. denticola effectively were important in the improvement of clinical conditions. P. gingivalis, B. forsythus and T. denticola may act as the microbial indicators for the prediction and assessment of treatment outcome.