BackgroundThe options for medical use of signaling molecules as stimulators of tissue regeneration are currently limited. Preclinical evidence suggests that fibroblast growth factor (FGF)-2 can promote periodontal regeneration. This study aimed to clarify the activity of FGF-2 in stimulating regeneration of periodontal tissue lost by periodontitis and to evaluate the safety of such stimulation.Methodology/Principal FindingsWe used recombinant human FGF-2 with 3% hydroxypropylcellulose (HPC) as vehicle and conducted a randomized double-blinded controlled trial involving 13 facilities. Subjects comprised 74 patients displaying a 2- or 3-walled vertical bone defect as measured ≥3 mm apical to the bone crest. Patients were randomly assigned to 4 groups: Group P, given HPC with no FGF-2; Group L, given HPC containing 0.03% FGF-2; Group M, given HPC containing 0.1% FGF-2; and Group H, given HPC containing 0.3% FGF-2. Each patient underwent flap operation during which we administered 200 µL of the appropriate investigational drug to the bone defect. Before and for 36 weeks following administration, patients underwent periodontal tissue inspections and standardized radiography of the region under investigation. As a result, a significant difference (p = 0.021) in rate of increase in alveolar bone height was identified between Group P (23.92%) and Group H (58.62%) at 36 weeks. The linear increase in alveolar bone height at 36 weeks in Group P and H was 0.95 mm and 1.85 mm, respectively (p = 0.132). No serious adverse events attributable to the investigational drug were identified.ConclusionsAlthough no statistically significant differences were noted for gains in clinical attachment level and alveolar bone gain for FGF-2 groups versus Group P, the significant difference in rate of increase in alveolar bone height (p = 0.021) between Groups P and H at 36 weeks suggests that some efficacy could be expected from FGF-2 in stimulating regeneration of periodontal tissue in patients with periodontitis.Trial RegistrationClinicalTrials.gov NCT00514657

The red complex, which includes Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia (formerly Bacteroides forsythus), are recognized as the most important pathogens in adult periodontal disease. These bacteria are usually found together in periodontal pockets, suggesting that they may cause destruction of the periodontal tissue in a cooperative manner. This article discusses the interspecies pathogenic interactions within the red complex.

Several microorganisms including Porphyromonas gingivalis and Bacteroides forsythus have been implicated to be etiologically important agents of periodontal disease. In this study, we determined the ability of combinations of periodontopathogenic microorganisms to cause tissue destruction in a murine abscess model. Although all bacterial combinations used in this study produced larger abscesses than did monoinfection of each bacterium, the combination of P. gingivalis and B.forsythus showed a synergistic effect on abscess formation. Since these two bacteria have been frequently found together in lesions of periodontitis, these results suggest the significance of their co-infection in the progression of periodontitis. P. gingivalis produces extracellular and cell-associated cysteine proteinases (gingipains) which appear to be involved in its virulence. The rgpA rgpB double and kgp mutants induced significantly smaller abscesses than the wild type. Moreover, the rgpA rgpB kgp triple (gingipain-null) mutant hardly showed lesion formation at all with the experimental conditions used in this study, indicating that these genes encoding gingipains are important for virulence of P. gingivalis. Mixed infection of these P. gingivalis mutants with B. forsythus showed an additive effect on abscess formation, indicating that the gingipains of P. gingivalis may play an important role in the pathological synergism between P. gingivalis and B. forsythus.

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Both hydrogen sulfide (H2S) and methyl mercaptan (CH3SH) are frequently detected in large amounts in malodorous mouth air. We investigated the bacterial composition of saliva of 30 subjects with severe oral malodor exhibiting extreme CH3SH/H2S ratios (high H2S but low CH3SH concentrations, n = 14; high CH3SH but low H2S concentrations, n = 16) and 13 subjects without malodor, using barcoded pyrosequencing analysis of the 16S rRNA gene. Phylogenetic community analysis with the UniFrac distance metric revealed a distinct bacterial community structure in each malodor group. The H2S group showed higher proportions of the genera Neisseria, Fusobacterium, Porphyromonas and SR1 than the other two groups, whereas the CH3SH group had higher proportions of the genera Prevotella, Veillonella, Atopobium, Megasphaera, and Selenomonas. Our results suggested that distinct bacterial populations in the oral microbiota are involved in production of high levels of H2S and CH3SH in the oral cavity.

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BackgroundTo evaluate the effects of the lactic acid bacterium Lactobacillus salivarius on caries risk factors.MethodsThe study was performed in 64 healthy volunteers to evaluate the effects of L. salivarius-containing tablets on caries risk factors. The participants were divided randomly into four groups, and took tablets containing L. salivarius WB21, L. salivarius TI 2711, Ovalgen® DC (antibody against glucosyltransferase from Streptococcus mutans), or xylitol. Levels of mutans streptococci and lactobacilli, amount of salivary flow, salivary pH, and salivary buffering capacity were assessed before and after taking the tablets. Subsequently, a short-term administration trial using L. salivarius WB21-containing tablets was performed in eight healthy volunteers. The participants took L. salivarius WB21-containing tablets (2.0 × 109 colony forming units/day) for 2 weeks, and the numbers of mutans streptococci in saliva were counted.ResultsThe levels of mutans streptococci seemed to decrease in the L. salivarius WB21, TI 2711, and Ovalgen® DC groups compared to the xylitol group, with no significant differences between the groups. Lactobacilli levels significantly increased in the L. salivarius WB21 and TI 2711 groups compared to the other groups. Concerning salivary flow and salivary pH, no significant differences were observed between the groups. The salivary buffering capacity significantly increased in the L. salivarius TI 2711 group (P = 0.003) and Ovalgen® DC group (P = 0.002) compared to the xylitol group. The short-term administration trial showed that the L. salivarius WB21-containing tablets significantly decreased the number of mutans streptococci (P = 0.039).ConclusionL. salivarius-containing tablets were suggested to increase resistance to caries risk factors.Trial registrationUMIN000013160 (registration date: February 14, 2014).

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