A clinical study of bacterial contamination of chlorhexidine-coated filaments of an interdental brush.

The purpose of this study was to assess the effectiveness of a chlorhexidine coating on the nylon filaments of an interdental brush in reducing bacterial contamination from actual clinical usage. In addition, the residual antimicrobial capacity of the coating over time from clinical exposure was studied. The same type of interdental brush, one with chlorhexidine-coated nylon filaments (antibacterial) and one with uncoated (control) nylon filaments was used with 20 subjects who were participating in a periodontal maintenance program. All subjects had more than four interproximal spaces large enough to accommodate the interdental brush at the start of the study. The subjects served as their own controls in this cross-over design. They used their brushes daily for one and two weeks, respectively. After the last use, each brush was kept in a controlled environment (20-22 degrees C, 65% relative humidity) for 24 hours for air drying. It was found that antimicrobial activity was detected on the chlorhexidine-coated filaments, even after one or two weeks of storage. The mean residual antimicrobial activity of the test filaments at one week was significantly higher than that found on the filaments after two weeks. The mean number of bacteria attached to the antimicrobial filaments were significantly fewer than those on uncoated, control filaments at both one week and two weeks of usage. These results suggest that chlorhexidine-coated filaments on an interdental brush can significantly reduce bacterial contamination and retain this antimicrobial activity for up to two weeks of use.

Clinical evaluation of a dental rinse containing aluminum lactate for treatment of dentinal hypersensitivity.

The effectiveness of a dental rinse containing aluminum lactate, which was used as a daily home treatment for dentinal hypersensitivity, was evaluated in a 6-week, double-blind study. Fifty-six subjects who complained of cold and/or tactile hypersensitivity were randomly divided into two groups: one given a dental rinse containing 2.18% aluminum lactate (test group) and the other a vehicle control dental rinse (control group). Subjects in both groups were instructed to rinse with the assigned dental rinse and to brush their teeth twice daily. The hypersensitivity levels of the affected teeth were assessed at baseline and at 4 and 6 weeks by application of tactile, cold air and cold water stimuli, and scored against baseline. All hypersensitivity scores in both groups were decreased significantly at weeks 4 and 6 compared to the baseline (p < 0.001). The hypersensitivity scores for tactile, cold air and cold water stimuli in the test group were significantly lower at weeks 4 and/or 6 compared to those in the control group (p < 0.05). Furthermore, on the analysis for the teeth with apparent pain (score 2 or 3) at the baseline, the reduction rates of hypersensitivity scores for cold air and cold water stimuli in the test group were significantly greater than those in the control group (p < 0.05). These findings suggest that daily home use of a dental rinse containing aluminum lactate is effective for treatment of dentinal hypersensitivity.

A major antigen on the outer envelope of a human oral spirochete, Treponema denticola.

Human oral spirochetes are prominent inhabitants of subgingival plaque in patients with periodontal disease. By immunoelectron microscopy using protein A-gold complexes and either polyclonal mouse antiserum against the 53-kDa antigen or 53-kDa-antigen-specific monoclonal antibody, a major polypeptide antigen, with a molecular weight of 53,000 (molecular size, 53 kilodaltons [kDa]), of a human oral spirochete, Treponema denticola ATCC 33520, was found to localize on the surface of the outer envelope.

Heterogeneity of virulence among strains of Bacteroides gingivalis.

The ability of fresh isolates of B. gingivalis to establish abscesses in the mouse model was studied by comparing them with established laboratory strains of B. gingivalis. Eight fresh isolates obtained from plaque associated with periodontal disease and grown under similar conditions as established strains were injected subcutaneously on the back of the mouse. All of these strains produced secondary lesions on the abdomen. Septicemia was associated with seven of the strains. Two commonly used laboratory strains, W50 and W83, also produced secondary lesions and septicemia. Five other laboratory strains produced only localized abscesses. On histologic examination, the strains that produced disseminated disease showed invasion of connective disease by individual bacteria that were not in clumps. The strains that produced localized abscesses were characterized by growing in colonies or clumps in the abscess cavity. Four synthetic enzyme substrates were examined to determine whether the differences between invasive and non-invasive strains were due to differences in proteolytic enzyme production. No differences in enzyme production could be demonstrated with the selected substrates.

Correlations between gingival crevicular fluid enzymes and the subgingival microflora.

Bacteroides gingivalis is a Gram-negative micro-organism implicated in the pathogenesis of adult periodontitis and producing relatively large amounts of specific enzymes. In the present study, subgingival samples taken from adults with moderate periodontitis were examined for the presence and relative amounts of enzymatic activity toward certain substrates. Enzyme levels were then correlated with clinical periodontal indices and microbiological analysis of subgingival plaque, including darkfield microscopy for bacterial morphotypes and immunofluorescence microscopy for B. gingivalis and Bacteroides intermedius. The results of this study indicate a significant positive correlation between levels of enzyme capable of degrading N-benzoyl-D,L-arginine-beta-naphthylamide hydrochloride, and subgingival B. gingivalis (r = 0.55). There was a much lower correlation coefficient between this enzyme activity and subgingival B. intermedius (r = 0.26). Statistically significant (p less than 0.01) positive correlations were also demonstrated between total bacterial cell counts and levels of enzymatic activity against N-benzoyl-D,L-arginine-beta-naphthylamide hydrochloride (r = 0.76), N-carbobenzoxy-glycyl-glycyl-L-arginine-beta-naphthylamide hydrochloride (r = 0.72), and glycyl-L-proline-4-methoxy-beta-naphthylamide hydrochloride (r = 0.72), and glycyl-L-proline-4-methoxy-beta-naphthylamide hydrochloride (r = 0.69). There were significant differences in the levels of these three enzymatic activities between sites exhibiting various degrees of clinical severity of gingival inflammation and harboring various proportions of B. gingivalis. The data from this study indicate that measurement of specific enzymatic activities in subgingival samples can be useful in the diagnosis of B. gingivalis-associated periodontitis.

Arylaminopeptidase activities of oral bacteria.

Protease and peptidase enzymes are thought to play a role in the virulence of many oral organisms, especially those associated with periodontal diseases. In order to evaluate the peptidases of periodontopathogens, we compared the arylaminopeptidase activities of Bacteroides gingivalis with those of other oral and non-oral bacteria. Sixty-three bacterial strains representing the prominent cultivable organisms in human periodontal pockets were tested, including representatives of the black-pigmented Bacteroides, Actinobacillus, Actinomyces, Campylobacter, Capnocytophaga, Eikenella, Fusobacterium, Haemophilus, Lactobacillus, Streptococcus, and Veillonella species. Each micro-organism was examined for its ability to hydrolyze 18 synthetic substrates of beta-naphthylamide derivatives of amino acids, dipeptides, and tripeptides. Quantitation of the enzyme activity was accomplished by colorimetric measurement of the amounts of released beta-naphthylamines. N-CBz-glycyl-glycyl-L-arginine-beta-naphthylamide was readily cleaved by B. gingivalis, but slightly or not at all by the other oral strains tested. L-arginine-beta-naphthylamide was cleaved by B. gingivalis, Capnocytophaga species, and Streptococcus species, but not readily by the other Bacteroides strains. Some dipeptide substrates tested, such as glycyl-L-arginine- and glycyl-L-proline-beta-naphthylamide, were strongly cleaved by B. gingivalis and weakly cleaved by other Bacteroides strains. Since high levels of N-CBz-glycyl-glycyl-L-arginyl-aminopeptidase activity are characteristic of B. gingivalis, its measurement may be valuable in the identification of this organism in clinical samples as an aid in diagnosis and monitoring of periodontal infections. Furthermore, this and other aminopeptidases produced by B. gingivalis and other oral organisms may play a role in the tissue destruction seen in periodontal disease.