Biochemical and serological characterization of Bacteroides intermedius strains isolated from the deep periodontal pocket.

Fifty-one fluorescence-positive black-pigmented Bacteroides strains obtained from 51 patients with deep periodontal pockets (greater than 6 mm) were identified and characterized. Fifty of these strains were presumptively identified as Bacteroides intermedius according to the indole reaction. This was confirmed by further biochemical characterization. The 50 strains from diseased sites were then compared with 16 B. intermedius strains isolated from periodontally healthy individuals with no signs of destructive periodontal disease. Tests for antimicrobial susceptibility showed similar patterns for all 50 pocket-derived strains, except for one beta-lactamase-positive strain that was resistant to penicillin G and ampicillin. Forty-seven strains were tested for binding of three monoclonal antibodies defining three distinct serogroups of B. intermedius. Thirty-one strains belonged to serogroup I, three to serogroup II and thirteen to serogroup III. In comparison to the strains from the shallow periodontal pockets, serogroup I was significantly overrepresented in the patient group with periodontal disease. We conclude that saccharolytic black-pigmented Bacteroides species from deep periodontal pockets constituted, with very rare exceptions, a biochemically homogeneous but antigenically heterogeneous group of B. intermedius and that serogroup I is predominantly found in deep periodontal lesions.     

Impaired cytotoxicity in Papillon-Lefèvre syndrome

Papillon-Lefèvre syndrome (PLS), palmoplantar hyperkeratosis with periodontitis, has been genetically characterized. However, suspected associated immune dysfunctions remain elusive. The purpose of this study was to evaluate peripheral blood lymphocyte levels and natural killer (NK) cell cytotoxicity in PLS. Twenty patients and 20 healthy controls were examined. Peripheral blood lymphocytes were analyzed by flow cytometry for surface markers. NK cell cytotoxicity against K562 cells was determined by means of a 51Cr release assay. White blood cell differential and proportions of B-, T-, T-helper, T-suppressor, and NK cells revealed only sporadic borderline variations from control values. In contrast, NK cell cytotoxicity was consistently and severely depressed (32-53% of control values) in all patients. To the best of our knowledge, this newly described impairment of NK cell cytotoxic function is the first consistent immune dysfunction reported in PLS. This suggests that the impaired NK cell cytotoxicity might contribute to the pathogenesis of PLS-associated periodontitis.     

Patient-based assessments of clinical periodontal conditions in relation to alveolar bone loss

BACKGROUND: Limited subject-based information exists on the relationship between clinical and radiographic periodontal data. AIMS: To use subject-based data to assess the extent of concurrence between clinical and radiographic information, and to study what clinical information best predicts alveolar bone loss (ABL). Material and Methods: Subject-based data on smoking habits, bleeding on probing, plaque scores, pocket probing depth (PD), and evidence of alveolar BL were obtained, and functional periodontal pentagon risk diagrams (PPRDs) were studied from 168 consecutive subjects attending a medical clinic. RESULTS: The mean age of the subjects was 62.7 years (SD+/-9.0). The average number of teeth was 21.3 (SD+/-8.0) with on average 5.6 molars remaining (SD+/- 3.9). In this subject cohort, 33.1% had never smoked, 44.2% had quit smoking, and 22.7% were currently smokers. Mean plaque and bleeding scores were high or 60.2% (SD+/-24.0) and 53.1% (SD+/-23.6), respectively. PDs >or=6.0 mm were found in 55.9% of the subjects. Binary logistic regression analysis demonstrated that tooth loss and proportional plaque scores were the predominant factors included in the equations associated with ABL. Wald coefficients varied between 3.99 and 9.15, and with p-values between 0.05 and 0.01. When included, the PPRD score became the exclusive factor at several cut-off levels (Wald's coefficients between 19.8 and 15.6, p<0.001). Consequently, the best receiver operator curve was identified for the PPRD at the >40% cut-off ABL level (area under the curve: 0.81; 95% CI: 0.74-0.89; p<0.001). CONCLUSIONS: The number of teeth lost and the proportion of plaque scores provided significant predictive factors for ABL. The functional PPRD demonstrated an exclusive and highly predictable association with ABL. Subject-based proportional data for PDs >4.0 mm provided poor substitute measures for the extent of ABL.     

The short-term treatment effects on the microbiota at the dorsum of the tongue in intra-oral halitosis patients—a randomized clinical trial

Objectives

This study aims to assess the effects of rinsing with zinc- and chlorhexidine-containing mouth rinse with or without adjunct tongue scraping on volatile sulfur compounds (VSCs) in breath air, and the microbiota at the dorsum of the tongue.

Material and methods

A randomized single-masked controlled clinical trial with a cross-over study design over 14 days including 21 subjects was performed. Bacterial samples from the dorsum of the tongue were assayed by checkerboard DNA–DNA hybridization.

Results

No halitosis (identified by VSC assessments) at day 14 was identified in 12/21 subjects with active rinse alone, in 10/21with adjunct use of tongue scraper, in 1/21 for negative control rinse alone, and in 3/21 in the control and tongue scraping sequence. At day 14, significantly lower counts were identified only in the active rinse sequence (p?<?0.001) for 15/78 species including, Fusobacterium sp., Porphyromonas gingivalis, Pseudomonas aeruginosa, Staphylococcus aureus, and Tannerella forsythia. A decrease in bacteria from baseline to day 14 was found in successfully treated subjects for 9/74 species including: P. gingivalis, Prevotella melaninogenica, S. aureus, and Treponema denticola. Baseline VSC scores were correlated with several bacterial species. The use of a tongue scraper combined with active rinse did not change the levels of VSC compared to rinsing alone.

Conclusions

VSC scores were not associated with bacterial counts in samples taken from the dorsum of the tongue. The active rinse alone containing zinc and chlorhexidine had effects on intra-oral halitosis and reduced bacterial counts of species associated with malodor. Tongue scraping provided no beneficial effects on the microbiota studied.

Clinical relevance

Periodontally healthy subjects with intra-oral halitosis benefit from daily rinsing with zinc- and chlorhexidine-containing mouth rinse.     

Comparative study of subgingival microbiological sampling techniques.

The presence of specific bacteria in subgingival plaque has been used as an indicator of active periodontal disease. The technique of subgingival sampling may conjecturally influence the identification and enumeration of microorganisms reported. In this study, paper point sampling and scaler sampling are compared. Subgingival samples using both methods were taken from three surfaces in each of 12 patients at the following time points: at each of two appointments one week apart before treatment and at each of two appointments 12 and 13 weeks following treatment. Microbiological analyses were undertaken to determine the total number of colony forming units, the proportions of suspected periodontal pathogens, and the number of spirochetes using phase contrast microscopy. Significantly higher numbers of colony forming units and spirochetes were found for paper point sampling both before and after treatment.