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Notes: Abstract Oral bacteria play an important role in the causation of oro-facial abscesses. However, they can also be involved in brain, liver and lung abscesses. To persist, it is essential that these bacteria can grow on those sites. The main source of nutrients for growth in abscesses is likely to be tissue exudate, which is rich in serum-derived proteins, and relatively poor in free amino acids and carbohydrates. Degradation of intact proteins seems a crucial step in providing the pep-tides necessary for energy generation. The aim of this study was to investigate the capacity of microorganisms from asscesses to degrade serum proteins, in particular immunoglobulins. To this end, samples were taken by aspiration from 16 odontogenic abscesses. It was found that pus from abscesses differed strongly in the concentration of viable bacterial cells. The ability of the abscess microflora to degrade serum proteins was investigated after growth of the sample in heat–inactivated human serum. The microflora from abscesses with a high concentration (n= 10) of bacteria strongly degraded immunoglobulins, whereas breakdown of immunoglobulins was virtually absent after growth of the microflora from low–bacterial concentration (n= 6) abscesses. Bacteriological analyses revealed the presence of at least one proteinase-producing species, like Porphyromonas, black-pigmented Prevotella species, or Actinomyces meyeri, in abscesses with a high density of bacteria, but not in those with low bacterial density. The results indicate that the capacity lo degrade intact proteins, in particular immunoglobulins, is a major determinant of bacterial growth in abscesses.

Notes: The proteolytic activities of oral bacteria are thought to play an important role in the aetiology of dental abscesses. Bacteria-derived proteases may contribute to tissue destruction, and are likely to impair host defence by degrading immunoglobulins and complement. Degraded periodontal tissue and tissue fluid are likely to constitute essential sources of nutrients in the abscess. Tissue fluid, which is derived from serum, is rich in protein and poor in carbohydrate, suggesting that breakdown of protein and fermentation of amino acids is a crucial step to generate energy for growth of the microflora. The number of oral bacterial species that perform hydrolytic cleavage of protein into polypeptides, the first step in protein degradation, is relatively small compared to the large majority of peptidase-producing species. In this study, we therefore investigated the growth-promoting effect of proteinase-producing species like Prevotella intermedia and Actinomyces meyeri on the growth of some non-proteinase producing bacteria in mixed cultures. We used serum as a substitute for the supposed natural substrate of the abscess microflora. The breakdown of serum proteins was investigated using capillary electrophoresis. Poor growth was found in mono- and mixed cultures of non-proteinase producing species Eubacterium lentum. Fusobacterium nucleatum, Peptostreptococcus micros, and Streptococcus intermedius. The presence of P. intermedia in mixed cultures strongly enhanced growth of these 4 species, according to the hypothesis that the growth of the mixed cultures was peptide-limited. The enhanced growth of P. intermedia in pronase-digested serum indicated peptide-limited growth of this organism in serum, despite its production of proteinase. We found that growth of monocultures of Actinomyces meyeri was poor. In contrast, A. meyeri grew well in mixed cultures and its presence stimulated growth of F. nucleatum and P. micros, suggesting a synergistic relationship. The growth of mono- and mixed cultures was investigated using one representative strain of each species. Thus, there is a small risk of having selected unique strains. Proteinase inhibitors reduced the growth of Porphyromonas gingivalis, Prevotella nigrescens, and P. intermedia in trypticase peptone-yeast extract medium with, and without, IgG. Our study indicated that proteinase-producing organisms play a key role in mixed cultures of oral bacteria in human serum by providing polypeptides for growth. This may explain their association with dental abscesses.

Notes: Abstract. Experimental mouthrinses containing 0.4% zinc sulphate and 0.15% triclosan were compared with a chlorhexidne and a negative control mouthrinse in a 3-week clinical trial. The zinc/triclosan mouthrinses 1 and 2 differed in their ethanol and humectant contents used to deliver the triclosan. The experimental protocol employed the partial mouth gingivitis design, whereby participants wear a toothshield during toothbrushing. Gingival health at baseline was established by professional cleaning, oral hygiene instruction and effective toothbrushing 3 × per day during a pre-experimental period of 2 weeks. The mouthrinses were subsequently used 2 × daily following normal toothbrushing during 3 weeks. The pre-experimental oral hygiene phase very effectively reduced plaque levels and gingival bleeding. During the rinsing period, in the absence of mechanical removal of plaque from the protected teeth, gingival bleeding rose to above the prestudy level in the negative control group. The increments (change from baseline to 21 days) of plaque and bleeding scores for the zinc/triclosan mouthrinse 1 were significantly lower than those in the negative control group. As expected, plaque and gingivitis scores were lowest in the group that rinsed with chlorhexidine. The results extend previous observations on the efficacy of the zinc/triclosan system to maintain gingival health.

Notes: Abstract. The aim of this study was to monitor the presence of sulfate-reducing bacteria (SRB) at different sites in the mouths of both healthy individuals and periodontitis patients. In 20 healthy subjects and 21 periodontitis patients, samples were taken from the palate, vestibulum, dorsum of the tongue, supragingival plaque, and periodontal pockets. In order to demonstrate growth of SRB, samples were incubated in an anoxic chamber in a reduced growth-medium for SRB, with an iron-indicator for sulfide production. The SRB were detected throughout the oral cavity. They were found on the mucosa in 10% of both healthy subjects and periodontitis patients. On the tongue and in supragingival plaque, the frequency of detection was slightly higher (22% of the subjects). In contrast, 86% of the periodontitis patients harbored SRB in one or more pockets. In 1/3 of the patients, SRB were present in all 3 pockets that were sampled. The data indicated that SRB belong to the normal oral microbiota, and have a preference for periodontal pockets.

Notes: Background, aims: Oral sulfate-reducing bacteria are involved in several clinical categories of periodontitis. The aim of this cross-sectional study was to compare the presence of sulfate-reducing bacteria (SRB) with other putative pathogens including spirochetes, Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Porphyromonas gingivalis, and Treponema denticola in periodontal lesions.Method: Periodontal SRB were detected by enrichment culture and compared with a microscopic spirochete count (n=168). Species-specific oligonucleotide probes directed against the 16S rRNA were employed to determine the presence of A. actinomycetemcomitans, P. gingivalis, B. forsythus, and T. denticola (n=55).Results: A significant positive correlation was observed between the presence of SRB and the proportions of spirochetes in subgingival plaque, although the 2 bacterial groups also occurred separately. SRB tended to be negatively correlated with the presence of A. actinomycetemcomitans. In contrast, all pockets with SRB harbored either T. denticola, or both T. denticola and B. forsythus (12/14) before therapy. Interestingly, the combination of SRB with P. gingivalis occurred in 32% of the periodontal pockets before treatment. After initial periodontal therapy, the prevalence of this combination was reduced to 2% of the sites, and to 25% of the sites in recall patients.Conclusion: The presence of SRB was positively correlated with T. denticola, B. forsythus, and P. gingivalis in periodontal lesions. These suspected pathogens form a complex strongly associated with destructive periodontitis.

Notes: Background, aims: Sulfate-reducing bacteria (SRB) may be etiologically involved in destructive periodontal diseases. These strictly anaerobic bacteria utilize fermentation products for energy conservation by reduction of sulfate to sulfide. This toxic product can accumulate in periodontal pockets in concentrations causing cellular destruction. SRB depend on an actively degrading microbiota to produce a reduced environment, fermentation products and sulfate. The detection frequency of these bacteria is strongly increased in periodontitis compared with healthy sites in the oral cavity.Method: In this study, the presence of SRB was determined in relation to clinical features of the patients and to site-specific clinical parameters of periodontitis, such as pocket depth, bleeding and attachment level. Patients with clinical characteristics of severe periodontitis (n=87) were included in the study, 78 were untreated patients and 9 patients were in maintenance care after treatment. Samples were taken (n=261) from the deepest periodontal pockets, and presence of SRB was determined by enrichment culture in an anoxic chamber.Results: In 64% of the patients, SRB were present in at least 1 pocket. They occurred among patients from 23 to 57 years old, and tended to prevail among patients older than 30 years. There was a tendency to increased SRB occurrence among patients with more than 50% of bleeding sites, or with several angular bony defects or furcations. In 44% of the periodontal pockets SRB were present. They tended to prevail in pockets showing bleeding on probing, furcations, angular bony defects, or an endodontal complication. Presence of SRB was positively correlated with increased pocket depth (p〈0.05). SRB were found to be associated with various clinical categories of periodontitis, including early onset periodontitis, rapidly progressive periodontitis, adult periodontitis, and refractory periodontitis. Although SRB predominated among patients with an adult form of periodontitis, i.e., with an occurrence of 72%, there was no significant correlation with age of the patient. Among treated patients under maintenance care, SRB prevalence was significantly reduced in comparison with untreated patients (p〈0.02). Occurrence of SRB in periodontal pockets showed an odds ratio of 11.2 in comparison with healthy oral sites.Conclusion: Periodontal sulfate-reducing bacteria are associated with several clinical categories of periodontitis and with periodontal sites of increased pocket depth.

Notes: A description is given of a colorimetric method to measure the masticatory function. It is based on the release of dye when chewing raw carrots. Information is given about the reproducibility of the method. The procedure takes 30 min for eitht tests on one subject and can be carried out with standard laboratory epuipment.

Notes: The aim of this study was to test the effect of chlorhexidine gel application on periodontal health of abutment teeth in patients with overdentures. 19 patients with immediate overdentures were distributed ar random among 2 experimental groups. In these groups, a placebo and chiohexidine gel were daily applied. Patients were recalled at 6-month intervals over a period of 2 years. In both groups, pocket depth, tooth mobility and bleeding index were initially found to decrease after insertion of the overdenture. In the chlorhexidine group. the bleeding index remained very low over the 2-year period. whereas in the placebo group. the bleeding index gradually returned to the baseline values. The pocket depth in the chlorhexidine group remained below the baseline value. in contrast to values in the control group. The width of the attached gingiva decreased in both the groups. but less in the chlorhexidine group.

Notes: Three different capsule or extracellular slime producing microorganisms: Rothia, Neisseria and Bacterionema were tested in SPF Osborne-Mendel rats for their ability to stimulate plaque formation and their effect on the gingiva. Gingival inflammation in the rats was evaluated in histological sections of buccal gingivae.All three the test strains were found to stimulate plaque formation. The high plaque score in the inoculated groups of rats was found to be attended by an increase in the area of infiltrated gingival tissue.