Porphyromonas gingivalis, a major etiological agent of adult periodontitis, has two distinctly different types of fimbriae on the cell surface. The major fimbriae, which consist of a 41-kDa fimbrillin of P. gingivalis ATCC 33277, have been known to induce inflammatory cytokine production in murine peritoneal macrophages. In this study, we examined the effects of the minor fimbriae of P. gingivalis, composed of a 67-kDa fimbrillin, on cytokine production in murine peritoneal macrophages and the ability to induce osteoclast differentiation. Murine peritoneal macrophages were stimulated with P. gingivalis 67-kDa minor fimbriae for 24 h, then the levels of interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha and IL-6 production were determined by enzyme-linked immunosorbent assay (ELISA). To estimate osteoclast differentiation, mouse osteoclast precursors were placed on dentine slices, and cultured with or without P. gingivalis 67-kDa minor fimbriae for 7 days. P. gingivalis 67-kDa minor fimbriae clearly induced IL-1beta, TNF-alpha and IL-6 production in mouse macrophages. Furthermore, pit formations on the dentine slices were significantly extended when the osteoclast precursors were incubated with P. gingivalis 67-kDa minor fimbriae. Pretreatment with anti-Toll-like receptor 2 (TLR2) antibody significantly inhibited IL-1beta, TNF-alpha and IL-6 induction (P<0.05) in mouse macrophages and pit-forming activity of osteoclast precursor cells stimulated with P. gingivalis 67-kDa minor fimbriae. These results suggest that P. gingivalis 67-kDa minor fimbriae may provoke host inflammatory response and be involved in periodontal tissue breakdown.

Fimbriae have been reported to play an important role in the adherence of Porphyromonas gingivalis to oral surfaces and possibly in triggering host responses. P. gingivalis ATCC 33277 has two distinctly different fimbriae expressed on the cell surface. The 67-kDa fimbriae differ in size and antigenicity from the earlier reported FimA, a major 41-kDa fimbrial component of P. gingivalis. Expression of the 67-kDa fimbriae on the cell surface of a fimA mutant was investigated by electron microscopy. The 67-kDa fimbrial protein was purified from the fimA mutant by sonication, precipitation, and chromatography on a DEAE Sepharose CL-6B column. The N-terminal amino acid sequence of the 67-kDa fimbrillin was distinct from that of the 41-kDa fimbrillin. Moreover, we have found that the 67-kDa fimbrial protein from P. gingivalis ATCC 33277 induced IL-1alpha, IL-beta, IL-6 and TNFalpha cytokine expression in mouse peritoneal macrophages. These results suggest that P. gingivalis 67-kDa fimbriae may play a part in the inflammatory response during the development of periodontal diseases.

Summary Frequent or persistent malodor (halitosis) represents a considerable embarrassment to those affected. French pine bark extract, Pycnogenol ® (PYC), has displayed antibacterial activity against a broad range of bacterial species. In the present study, anticipated benefits of PYC on diminishing halitosis were investigated. Ten healthy males and 11 females, aged 40.1612.3 y, were recruited based on threshold breath sulfur compounds presence, diagnosed by portable gas chromatography. Subjects were randomly assigned to either sugar-free gums, or gums bearing an additional 2.5 mg PYC per piece. The subjects were required to consume two pieces of PYC or placebo gum six times daily for 15 min. The levels of volatile sulfur compounds (VSCs), measured by OralChroma TM , and tongue-coating score were recorded at baseline, 2, and 4 wk. Hydrogen sulfide-producing bacteria in saliva were cultured on Brucella blood agar plates containing 0.05% cysteine, 0.12% glutathione, and 0.02% lead acetate. The group consuming PYC chewing gum reduced exhaled hydrogen sulfide, methyl mercaptan and dimethyl sulfide significantly (p,0.01) after 2 wk versus baseline. Continuation of daily PYC-gum consumption for 4 wk remarkably lowered the tongue-coating score and exhaled hydrogen sulfide was significantly decreased compared to the placebo group. PYC chewing gum significantly reduced hydrogen sulfide-producing bacteria in saliva after 4 wk (p,0.01), with no effects observed in the placebo control. The results suggest that PYC chewing gum is effective in reducing oral malodor by decreasing the accumulation of tongue coating and the number of hydrogen sulfide-producing bacteria in saliva.

Dental materials are inevitably contaminated with oral microorganisms. To prevent transmission of infectious diseases, impressions need to be disinfected. In the present study, we examined the disinfection effects on impression materials and biofilm removal by sodium dichloroisocyanurate (SDIC) . Exponentially growing Streptococcus mutans, Escherichia coli, Staphylococcus aureus and Candida albicans, and dental plaque bacteria were suspended in phosphate buffered saline (PBS) and exposed for 1, 5 and 10 min to 1 mL of the 10 ppm, 100 ppm, 1,000 ppm, and 10,000 ppm SDIC solutions. The bactericidal effect was evaluated by colony forming units of each microorganisms. Moreover, the effect of SDIC solution on S. mutans biofilm was examined. Bactericidal effects of SDIC solutions on oral bacteria on dental impression surfaces were assessed and the surface quality of dental casts after immersion in SDIC solution for 30 min was observed under a scanning electron microscope. The number of all bacterial strains, including plaque bacteria, were significantly decreased by SDIC solution treatment in a dose-dependent manner. Significant S. mutans biofilm removing activity of SDIC was observed in 1,000 and 10,000 ppm solution. The number of oral bacteria adhering to the surfaces of impressions markedly decreased following 10-min immersion in the 1,000 ppm SDIC solution. The 30-min immersion of dental impression in the 1,000 ppm SDIC solution did not adversely affect the surface roughness of dental casts. The results indicate that SDIC Solution is useful to deactivate oral bacteria on dental impression.