The Study Of Adherence Of Periodontal Pathogens To Collagen-treated Hydroxyapatite (C-HA)

Adhesion of oral bacteria is essential to biofilm formation. The abilities of oral bacteria to adhere to tooth surface are different, which are associated with their pathogenicity. Collagen is one of the most abundant structural components of the dentin and cementum. 50% of cementum are collagen. Periodontal pathogens can adhere to collagen. There are few reports about which periodontal bacteria can adhere directly to root surface, and which has stronger binding ability.Objective The objective of this study was to compare the ability of 4 strains of periodontal pathogens (F.nucleatum, P.gingivalis H.actinomycetemcomitans, and P. intermedius) attaching to collagen-treated hydroxyapatite (C-HA)beads in order to evaluate the ability of the main periodontal pathogens to form the biofilm on root surface.Method f.nucleatumATCC10953, P.gingivalisATCC33277, H.actinomycetemcomitansATCC29523, P. intermediusATCC25611 were obtained form the laboratory of oral biomedical engineering ministry of education, Sichuan university. The microorganisms were radiolabeled during growth in brain heart infusion broth (BHI broth) which contained ~3H-thymidine (10Ci/ml).The binding amount and binding percentage of four strains to C-HA were measured and compared by ~3H-labeled binding assay. The adherent percent of bacteria to C-HA was detected by radioisotope scintillation counter.Results The differences of the percentage of relative adherence between EnucleatumATCC10953 and P.gingivalisATCC33277,as well as between H.actinomycetemcomitansATCC29523 and P.intermedius ATCC25611 could not be observed. However, the percentage of relative adherence of f.nucleatumATCC10953 and P.gingivalis ATCC33277 were higher than that of H.actinomycetemcomitans ATCC29523 and P.intermediusATCC25611 (P＜0.001), no matter cultured 24h or 48h. No significant difference of the percentage of the relative adherence of each stain between 24h and 48h culture time could be found.Conclusions Enucleatum and P.gingivalis exhibited strong binding ability to C-HA. Their adherence to root surface may play an important role in their local aggregation, biofilm formation during the development and recurrence of the periodontitis.