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Biomedical subjects

R F Müller

Publications and source records attributed to R F Müller.

At least 19 recordsLinked to original sources
PubMed1991

[Actinobacillus actinomycetemcomitans on oral mucosa].

The present study was carried out to delineate the parameters influencing the extracerevicular oral colonization of Actinobacillus actinomycetemcomitans. Numbers of cultivable A. actinomycetemcomitans in subgingival plaque samples, saliva, and samples from buccal and tongue mucosae were determined in 33 patients with A. actinomycetemcomitans-associated periodontitis. Subgingival samples from patients with localized juvenile periodontitis (LJP) had significantly higher levels of A. actinomycetemcomitans than samples obtained in non-LJP patients (740,000 vs. 59,000, median, p less than 0.05). Samples from buccal mucosae and saliva were infected with A. actinomycetemcomitans in 85 vs. 70%, and 77 vs. 65%, respectively. Multiple regression analysis of log 10-transformed counts of A. actinomycetemcomitans in samples from cheek as dependent variable yielded a significant influence of numbers of deep periodontal pockets and diagnosis. The occurrence of A. actionomycetemcomitans on buccal mucosa seems to reflect the overall subgingival load with the organism.

Adolescent↗
PubMed1990

Multiple periodontal abscesses after systemic antibiotic therapy.

Multiple periodontal abscesses were reported in medically compromised patients. We examined patients with a non-contributory medical history referred for the treatment of numerous periodontal abscesses. All patients had taken oral broad spectrum antibiotics 1 to 3 weeks prior to the outburst of the abscesses (8 patients: penicillin, 2 patients: tetracycline). The patients suffered from advanced periodontal disease, 82% of the examined sites showed probing depths greater than 3 mm, 56% attachment loss greater than 3 mm. Subgingival plaque samples were analysed from 2 different abscess sites. Bacteroides gingivalis (19/20), Fusobacterium nucleatum (13/20) and Streptococcus intermedius (13/20) were the most prevalent anaerobic microbiota. Strains resistant to the prescribed antibiotic were found in 55% (11/20) of the subgingival plaque samples. It was concluded that in patients with advanced periodontal disease, systemic antibiotic therapy without subgingival debridement may change the composition of the subgingival microbiota, thus favouring the outburst of multiple periodontal abscesses.

Adult↗
PubMed1990

Morphological compositions of subgingival microbiota in Actinobacillus actinomycetemcomitans-associated periodontitis.

Infrequent occurrence of spirochetes and rather low proportions of these organisms have been reported in localized juvenile periodontitis, where periodontal lesions often harbour large numbers of Actinobacillus actinomycetemcomitans, a suspected principal periopathogen strongly implicated in the pathogenesis of this and other forms of chronic periodontitis. We studied the association of subgingival A. actinomycetemcomitans with the morphological composition of the subgingival microbiota in a large population of patients suffering from advanced periodontitis. Subgingival plaque from the deepest pockets of every quadrant of their dentitions was sampled and pooled in 70 patients between 14 and 63 years of age, and analysed morphologically by phase-contrast microscopy. A minimum % similarity index was employed to define 4 clusters with different morphological composition of the floras. The actual proportion of A. actinomycetemcomitans was determined at 2 sites with deep periodontal pockets. All clusters harboured patients infected with A. actinomycetemcomitans. If present, in clusters predominated by motile rods or medium-sized spirochetes, the organism was found in rather low proportions (median 5.3% and 3.4%, respectively). However, the cluster with a pooled flora mainly consisting of coccoid cells revealed periodontal sites with A. actinomycetemcomitans in proportions of more than 53% (median), if the organism was present (p less than 0.01). We found a positive correlation between proportions of A. actinomycetemcomitans and cocci (R = 0.65) and negative correlations with spirochetes and motile rods (R = 0.61, R = -0.59, respectively). Cautious interpretation of subgingival plaque predominated by coccoid cells is recommended, if deep periodontal pockets and obvious signs of inflammation are present, since these pockets were found to be often infected with large numbers of A. actinomycetemcomitans.

Actinobacillus↗
PubMed1990

[Quantifying bacteriological findings in the subgingival flora].

The variation of selected bacteriological parameters was investigated in 25 untreated A. actinomycetemcomitans-associated periodontitis patients. Samples of subgingival plaque were collected twice within 6 weeks with paper points for cultivation as well as with curettes for analyses of the morphological composition. Total counts of colony forming units, counts of A. actinomycetemcomitans as well as proportions of spirochetes were determined. Our results suggest a high reproducibility of quantitative data if a standardised sampling procedure with paper points is employed. On the other hand, considerable differences were observed in the morphological composition of subgingival plaque.

Actinobacillus↗
PubMed1990

[Concentrations of A. actinomycetemcomitans in subgingival plaque following short-term minocycline therapy].

In the present study we examined alterations in the proportions of cultivable flora of A. actinomycetemcomitans (A.a.) in subgingival plaque of 25 patients with different forms of periodontitis, 7 days after systemic administration of 200 mg/d Minocycline-HCl. Remarkable shifts in the flora were apparent. Sites with low or extremely low initial levels of A.a. (less than 10%) showed an increase in mean proportions from 2.7% to 15.7% (p less than 0.01). A.a. was eliminated in only 18% of sites after 1 week of minocycline therapy. Subgingival scaling resulted in 80% of sites without detectable A.a. However, if present, the organism accounted for 51% of the cultivable microflora, on average. Our data emphasize the importance of a sufficiently extended period of antibiotic therapy and efficient mechanical debridement of all tooth surfaces to eliminate the organism.

Actinobacillus↗
PubMed1989

Actinobacillus actinomycetemcomitans contamination of toothbrushes from patients harbouring the organism.

The main ecological niche of Actinobacillus actinomycetemcomitans (A.a.) seems to be the periodontal pocket, but it can also be isolated from supragingival plaque, buccal and tongue mucosa, or saliva. We examined toothbrushes from 21 patients, all identified as harbouring moderate to large numbers of A.a. in subgingival plaque, for contamination with this organism. 29% of the toothbrushes presented by our patients yielded detectable numbers of A.a. Immediately after toothbrushing this figure rose to 62%, but dropped to 50% after 1 h. Numbers of isolated A.a. on toothbrushes were weakly correlated with the degree of periodontal destruction, and significantly more numbers of A.a. on toothbrushes could be detected if the organism was found on mucous membranes or in saliva. There was no association with gingival inflammation, supragingival plaque nor mean numbers of isolated subgingival A.a.

Actinobacillus↗
PubMed1989

[Vital staining and phase contrast microscopy results of plaque smears].

The information about the vitality of the plaque is limited. Only motile bacteria can be distinguished as alive. Vital staining allows to differentiate between living nonmotile rods and dead, previously motile rods. With increasing severity of the periodontal destruction, the proportion of alive respectively motile rods and vibrions increases. The vital staining shows very clearly the relation between destruction and living rods.

Adolescent↗
PubMed1989

[Electron microscopic visualization of microbial extracellular metabolic products in an in vitro test].

The present electron microscopic study was performed to investigate the glycocalyx changes of S. mutans species OMZ 176 during incubation with defined substrate limitation (sucrose) and with hydroxyapatite crystals. In an agar with 5 p. c. sucrose can be seen the build-up of proteoglycan complexes, and a strong cell free glycan production in order to hydroxyapatite crystals.

Cell Wall↗
PubMed1989

[Efficacy of a PVP-iodine compound on selected pathogens of the oral cavity in vitro].

The study was designed to test the efficacy of a PVP-iodine antiseptic agent on potentially pathogenic oral bacteria. A 0.5% concentration of the test compound was sufficient to inhibit the growth of 7 out of 8 tested strains. Only bacteroides gingivalis continued to grow during exposure to a 0.5 and 1% concentration of the test compound. Quantitative suspension experiments demonstrated that the onset of action occurred within five minutes. Quantitative suspension experiments with protein loading resulted in a lower efficacy of the tested agent. Results indicate that the tested compound may be recommended as an oral disinfectant.

Bacteria↗
PubMed1989

[Reduction of A. actinomycetemcomitans in the subgingival microflora of adult advanced periodontitis].

In 15 adult patients with severely advanced periodontal disease unrelated to localized juvenile periodontitis high numbers of A. actinomycetemcomitans (A. a.) were identified in samples of subgingival plaque (median log CFU 5.13). In order to correlate clinical conditions with bacteriological findings, in every patient 2 deep periodontal pockets were treated with a 3-phase regimen of minocycline administration, mechanical, and surgical periodontal therapy. A. a. was eliminated by minocycline alone in 2 cases. Minocycline in combination with subgingival scaling resulted in 6 patients in A. a. negative samples. Following termination of minocycline therapy, frequently increasing numbers of A. a. were observed. Patients showed significant gain in clinical attachment or reduction of probing pocket depth during different phases of therapy, but only if A. a. was suppressed close to or below the lower limit of detection (5 CFU/ml). Considerable problems with elimination of A.a. may be connected with frequently observed recurrent periodontal disease in these patients.

Actinobacillus↗