Synergistes group organisms of human origin

The bacterial division Synergistes represents a poorly characterized phylotype of which only a few isolates have been cultured, primarily from natural environments. Recent detection of Synergistes-like sequence types in periodontal pockets and caries lesions of humans prompted us to search the R. M. Alden culture collection (Santa Monica, Calif.) for biochemically unidentifiable, slow-growing, obligately anaerobic gram-negative bacilli. Here we report on five clinical isolates cultured from peritoneal fluid and two isolates from soft-tissue infections that together constitute three separate evolutionary lineages within the phylogenetic radiation of the division Synergistes. One of these clusters was formed by the peritoneal isolates and had an 85% similarity to Synergistes jonesii, the first described Synergistes species, which was isolated from the rumen of a goat. The isolates from soft-tissue infections, on the other hand, formed two distinct lineages moderately related to each other with a similarity of approximately 78%. In addition, by using a newly designed 16S rRNA gene-based PCR assay with intended target specificity for Synergistes, we found that the dominant phylotype from a fecal sample was nearly identical to that of the strains obtained from peritonitis. Conversely, sequence types detected in periodontal pockets formed a separate cluster that shared a similarity of only 80% with the soft-tissue isolates. These findings suggest a high diversity of medically important Synergistes clades that apparently are unique to individual ecological niches in the human body. In conclusion, we now have available the first characterized human isolates of the division Synergistes which are colonizing, and probably infecting, several sites in the human body.

[Use of molecular genetic systems for diagnostics of inflammatory diseases of oral mucosa and periodontium]

Structure of bacterial microflora of periodontal pocket using classical cultural and molecular genetic methods (PCR and RT-PCR assays) was studied in patients with chronic generalized severe or intermediate periodontitis in acute phase and in healthy subjects. Structure of viral and fungal microflora using PCR or ELISA assays was studied also. Markers of Gram-negative bacteria (B. forsithus, T. denticola, A. actinomicetemcommitans, P. intermedia and P. gingivalis) were detected with different rates. Rate of detection of pigment-forming P. intermedia and P. gingivalis was significantly higher when PCR assay was used compared with traditional bacteriologic method. Detection rate of Candida albicans DNA in tooth-gingival fluid was virtually not different from one when cultural method was used. PCR assay is recommended as laboratory method for detection of DNA of microorganisms associated with inflammatory diseases of oral mucosa and periodontium.

Scaling and root planing and chlorhexidine mouthrinses in the treatment of chronic periodontitis: a randomized, placebo-controlled clinical trial

OBJECTIVE

Evaluation of the clinical and microbiological effects of scaling and root planing (SRP) alone or in combination with 0.12% chlorhexidine (CHX) rinsing.

METHODS

A blind, placebo-controlled, parallel-design, randomized clinical trial was conducted in 29 subjects with chronic periodontitis. Subjects were assigned to two therapeutic groups: control (SRP+placebo) and test (SRP+CHX during and up to 42 days post-therapy). Clinical and microbiological [N-benzoyl-dl-arginine-2-naphthylamide (BANA test)] examinations were performed at baseline, 42 and 63 days post-therapy.

RESULTS

Initially, intermediate sites (4-6 mm) in the test group showed less plaque accumulation, gingival bleeding, bleeding on probing and a greater reduction in attachment level and probing depth (PD) at 63 days after treatment. The initially deep sites (>6 mm) in the CHX group also showed a better reduction in plaque accumulation and in PD compared with the control group. Both therapies led to a microbiological improvement; however, the test subjects showed a higher frequency of BANA-negative sites after treatment, which was sustained over time (p<0.001). At 63 days, the control group presented 25 BANA-negative sites and 65 positive sites, and the test group 58 and 26, respectively.

CONCLUSION

The combination of CHX rinses and SRP leads to clinical benefits and to a better reduction in BANA-positive species.

Subgingival and tongue microbiota during early periodontitis

Periodontal infections have a microbial etiology. Association of species with early disease would be useful in determining which microbes initiate periodontitis. We hypothesized that the microbiota of subgingival and tongue samples would differ between early periodontitis and health. A cross-sectional evaluation of 141 healthy and early periodontitis adults was performed with the use of oligonucleotide probes and PCR. Most species differed in associations with sample sites; most subgingival species were associated with subgingival samples. Few species were detected more frequently in early periodontitis by DNA probes. Porphyromonas gingivalis and Tannerella forsythia (Tannerella forsythensis) were associated with early periodontitis by direct PCR. In conclusion, the microbiota of tongue samples was less sensitive than that of subgingival samples in detecting periodontal species, and there was overlap in species detected in health and early periodontitis. Detection of periodontal pathogens in early periodontitis suggests an etiology similar to that of more advanced disease.

Repeated oral hygiene instructions alone, or in combination with metronidazole dental gel with or without subgingival scaling in adult periodontitis patients: a one-year clinical study

The aims of the present study were to evaluate the clinical efficacy of, and to monitor microbiologically, repeated oral hygiene instructions alone or in combination with metronidazole 25% gel or subgingival scaling with or without metronidazole gel in treatment of new, residual or recurrent periodontal pockets in previously treated adult periodontitis patients. Ten suitable patients were included in this randomized single-blind clinical study with an intra-individual design. Clinical parameters were measured before and at 1, 3, 6, 9 and 12 months after treatment. Subgingival plaque samples were taken at every examination from one selected site in each quadrant. Smears from plaque samples were silver-stained and differential counting was performed under light microscopy at 1000X magnification. Four treatment modalities: (i) oral hygiene instruction (OHI) alone; (ii) OHI and metronidazole dental gel; (iii) OHI and subgingival scaling; (iv) OHI and subgingival scaling plus metronidazole gel, were randomly assigned to one quadrant of each patient. At the 12-month examination, the mean reductions in probing pocket depth were 2.6 mm after OHI alone, 2.8 mm after OHI and metronidazole gel, 3.3 mm after OHI and subgingival scaling and 2.6 mm after oral OHI and subgingival scaling plus metronidazole gel. The mean gains in probing attachment level were 2.2 mm, 1.9 mm, 2.7 mm and 1.6 mm, respectively. Although there were statistically significant differences in treatment responses between some treatment modalities at some time points, these were not considered to be clinically significant. Differential counts showed a shift towards a healthy microflora in response to all treatment modalities. From the 12-month results, it was concluded that the metronidazole 25% gel produced positive effects on the clinical parameters and on the subgingival plaque microbiological composition in new, residual or recurrent pockets in previously treated chronic periodontitis patients. However, the metronidazole gel alone or in combination with scaling does not seem to have any additional clinically significant therapeutic effects over and above those derived from improved oral hygiene resulting from monthly recalls, with or without subgingival scaling.

Wound healing of periodontal pockets using the diode laser: an interview

Laser technology appears to have a promising future in dentistry While these devices are still in their infancy it is important to understand the interaction of laser energy on the intraoral structures of the patient, and to evaluate its effect on bacteria responsible for periodontal disease. The following is an interview that relates the details of one important investigation into tissue response as conducted by the Department of Periodontics and Endodontics, SUNY at Buffalo School of Dental Medicine.

Effective use of the 810 nm diode laser within the wellness model

In recent years, periodontal treatment has evolved from a disease model to a perio-medical model that traces the causal pathway in a patient's care. Proper risk assessment and timely therapeutic intervention are key aspects of this model, as is the continued evaluation of the patient through effective follow-up. Of significant benefit in this paradigm shift is the 810 nm diode laser which can be used for bacterial reduction and sulcular debridement to disinfect the periodontally involved pocket and is suggested to initiate the body's host immunological response while maintaining the symmetry of the intraoral environment. This presentation highlights the application of the 810 nm diode laser (Odyssey, Ivoclar Vivadent, Amherst, NY) as it relates to this evolving model of patient care.

Expression of beta-defensin-2 in human gingival epithelial cells in response to challenge with Porphyromonas gingivalis in vitro

BACKGROUND AND OBJECTIVE

Human beta-defensin-2 (hBD-2) is an antimicrobial peptide that is produced by epithelial cells after stimulation with microorganisms and inflammatory mediators. Compared with gram-positive bacteria, gram-negative bacteria, which are typically detected in the periodontal pockets in periodontitis, elicit a stronger antibacterial peptide response of hBD-2 by epithelial cells. The purpose of this study was to investigate the expression of hBD-2 and relationships between it and inflammatory mediators in human gingival epithelial cells (HGEC) in response to challenge with Porphyromonas gingivalis in vitro.

MATERIAL AND METHODS

mRNA expression of hBD-2 in HGEC stimulated with or without P. gingivalis was assessed using a semiquantitative reverse transcription-polymerase chain reaction. Primary cultured HGEC were activated by live P. gingivalis, and inflammatory cytokine production was examined using an enzyme-linked immunosorbent assay.

RESULTS

The level of hBD-2 mRNA in HGEC treated with P. gingivalis increased with exposure time. After 48 h, the mRNA in P. gingivalis was significantly increased compared with that in control HGEC. The interleukin-8 production rate was much greater in stimulated HGEC than in the control HGEC, almost always showing a significant difference after 3 h. The production of interleukin-1beta was not increased as much as that of interleukin-8.

CONCLUSION

These findings suggest that the expression of hBD-2 in HGEC is P. gingivalis-dependently induced and is likely to be connected with the initial stage of the inflammatory response.

Detection and measurement of oral malodour in periodontitis patients

BACKGROUND & OBJECTIVES

Malodour has been correlated with the concentration of volatile sulphur compounds produced in the oral cavity by metabolic activity of bacteria colonizing the periodontal sites and the dorsum of the tongue. The aim of this study was to detect malodour in mouth air organoleptically and using a portable sulphide monitor and to correlate it with the clinical parameters, halitosis linked toxins and BANA, using tongue and subgingival plaque samples. The halitosis grading is also correlated with the microbial colonies of the subgingival plaque sample.

METHODS

20 patients with chronic periodontitis with 5-7 mm pocket depth, radiographic evidence of bone loss and presence of oral malodour participated in this study. Assessment of mouth air was done organoleptically and by using a portable sulphide monitor. The clinical parameter, plaque index (PI), gingival index (GI), gingival bleeding index (BI), were obtained from all the areas. Samples for BANA and to detect halitosis linked toxins were taken from the dorsal surface of the tongue and periodontal pockets ranging 5-7 mm. Halitosis related microbial colonies were identified using anaerobic culturing from the subgingival plaque.

RESULTS

The scores of PI, GI, BI and sample that tested positive for halitosis linked toxins and with the halitosis grading were not significant. The presence of tongue coating and the halitosis grading and toxin levels were significant. BANA has shown to be non contributory due to technical problems. Anaerobic culture has shown to identify Streptococcus, Bacteroides, Fusobacterium, Porphyromonas and Prevotella colonies.

INTERPRETATION & CONCLUSION

The results confirmed that there was no correlation between the clinical parameters, halitosis linked toxins and halitosis grading. The microbial colonies have shown to correlate with the presence of oral malodour.

Molecular epidemiology of oral treponemes in patients with periodontitis and in periodontitis-resistant subjects

The etiologic role of oral treponemes in human periodontitis is still under debate. Although seen by dark-field microscopy in large numbers, their possible role is still unclear since they comprise some 60 different phylotypes, most of which are still uncultured. To determine their status as mere commensals or opportunistic pathogens, molecular epidemiological studies are required that include both cultured and as-yet-uncultured organisms. Here we present such data, comparing treponemal populations from chronic periodontitis (CP) or generalized aggressive periodontitis (GAP) patients. As a periodontitis-resistant (PR) control group, we included elderly volunteers with more than 20 natural teeth and no history of periodontal treatment and no or minimal clinical signs of periodontitis. Almost every treponemal phylotype was present in all three groups. For most treponemes, the proportion of subjects positive for a certain species or phylotype was higher in both periodontitis groups than in the PR group. This difference was pronounced for treponemes of the phylogenetic groups II and IV and for Treponema socranskii and Treponema lecithinolyticum. Between the periodontitis groups the only significant differences were seen for T. socranskii and T. lecithinolyticum, which were found more often in periodontal pockets of GAP patients than of CP patients. In contrast, no difference was found for Treponema denticola. Our findings, however, strengthen the hypothesis of treponemes being opportunistic pathogens. It appears that T. socranskii, T. lecithinolyticum and group II and IV treponemes may represent good indicators for periodontitis and suggest the value of the respective probes for microbiological diagnosis in periodontitis subjects.

In vitro minocycline activity on superinfecting microorganisms isolated from chronic periodontitis patients

Chronic periodontitis is the most common type of periodontitis and it is associated with various species of microorganisms. Enteric rods, Pseudomonas, Staphyloccocus and Candida have been retrieved from periodontal pockets of patients with chronic periodontitis and correlated to cases of superinfection. Local or systemic antibiotic therapy is indicated to reinforce the effects of the conventional mechanical therapy. Minocycline has been suggested as one of the most effective drugs against periodontal pathogens. The aim of this work was to evaluate the minimal inhibitory concentration (MIC) of minocycline on superinfecting microorganisms isolated from the periodontal pocket and the oral cavity of individuals with chronic periodontitis. Isolates of Enterobacteriaceae (n = 25), Staphylococcus spp. (n = 25), Pseudomonas aeruginosa (n = 9) and Candida spp. (n = 25) were included in the study. Minimal inhibitory concentrations (MIC) of minocycline were determined using the Müeller-Hinton agar dilution method. Staphylococcus spp. isolates were the most sensitive to minocycline with a MIC of 8 µg/mL, followed by Enterobacteriaceae with a MIC of 16 µg/mL. The concentration of 16 µg/mL inhibited 96% of Candida spp. isolates. The MIC for 88.8% of the isolates of Pseudomonas aeruginosa was 128 µg/mL. A concentration of 1,000 µg/mL was not enough to inhibit 100% of the tested isolates.

Aggressive periodontitis in a 16-year-old Ghanaian adolescent, the original source of Actinobacillus actinomycetemcomitans strain HK1651 - a 10-year follow up

The highly leukotoxic JP2 clone of Actinobacillus actinomycetemcomitans is strongly associated with periodontitis in adolescents. Availability of the DNA sequence of the complete genome of A. actinomycetemcomitans strain HK1651, a representative strain of the JP2 clone (http://www.genome.ou.edu/act.html), has provided new possibilities in basic research regarding the understanding of the pathogenesis of A. actinomycetemcomitans in periodontitis. This case report describes the periodontal treatment of the original source of A. actinomycetemcomitans HK1651, a 16-year-old Ghanaian adolescent girl with aggressive periodontitis. The bacterial examination involved polymerase chain reaction analysis for presence of JP2 and non-JP2 types of A. actinomycetemcomitans. The treatment, including periodontal surgery supplemented by antibiotics, arrested the progression of periodontitis for more than 10 years. Initially, infection by A. actinomycetemcomitans, including the JP2 clone, was detected at various locations in the oral cavity and was not limited to the periodontal pockets. Post-therapy, the JP2 clone of A. actinomycetemcomitans disappeared, while the non-JP2 types of A. actinomycetemcomitans remained a part of the oral microflora.

Tongue coating and tongue brushing: a literature review

The present paper reviews the role of the tongue as a habitat for oral microorganisms and the potential need for tongue cleaning as part of daily oral hygiene. In addition tongue coating is described. Many microorganisms have been found colonizing the dorsum of the tongue. Some studies find a positive effect to tongue brushing on bacterial counts on the tongue. On the other hand there are also studies that do not find any differences in bacterial counts before or after tongue brushing. Bacteria colonizing the tongue and periodontal pockets play an important role in the production of volatile sulphur compounds in periodontal health and disease. These compounds can be the cause of oral malodour. The amount of tongue coating in patients complaining of halitosis was significantly greater than in patients without halitosis. Tongue brushing on a regular basis, particular aiming at removing the coating on the dorsum of the tongue, has been found to be fruitful in reducing oral malodour. Studies investigating the role of tongue brushing and plaque accumulation or gingival inflammation show conflicting results. It is clear that the tongue forms the largest niche for microorganims in the oral cavity. However, on the basis of literature, there appears to be no data to justify the necessity to clean the tongue on a regular basis. One exception would be oral malodour.

Chronic oral inflammation and the progression of periodontal pathology in the third molar region

PURPOSE

To assess the association between risk markers of chronic oral inflammation and changes over time in periodontal probing depth (PD) in the third molar region, the distal of a second molar, or around a third molar.

SUBJECTS AND METHODS

The data from these analyses are part of a study of subjects enrolled with 4 asymptomatic third molars with adjacent second molars in an institutional review board-approved longitudinal trial. Full-mouth periodontal probing was conducted at enrollment and follow-up. Enrollment levels of periodontal pathogens and gingival crevicular fluid inflammatory mediators were assayed as indicators of the degree of oral inflammation. Subjects were categorized as those who had at least a 2 mm change in periodontal PD between baseline and follow-up in the third molar region and those who did not. The relationship between aggregated subject baseline PD, levels of periodontal pathogens, and gingival crevicular fluid IL-1 beta, and the proportion of subjects with changes in PD >or=2 mm versus those with PD <2 mm were compared with Cochran-Mantel-Haenzsel statistics. Level of significance was set at 0.05. Risk assessment models for a change in PD >or=2 mm were developed using logistic regression analysis.

RESULTS

Twenty-four percent of 254 subjects exhibited a change in PD from baseline to follow-up of >or=2 mm in the third molar region. Of these, 95% had a baseline PD of >or=4 mm. Both high (>or=10(5)) "orange" and "red" complex bacteria and PD of >or=4 mm detected at enrollment were significantly associated with a change in PD >or=2 mm. Odds of a change in PD >or=2 mm were increased if baseline pathogen levels were >or=10(5) or a PD of >or=4 mm was detected at enrollment.

CONCLUSION

Our findings are consistent with chronic oral inflammation leading to a progression of periodontal disease in the third molar region.

Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis subgingival presence, species-specific serum immunoglobulin G antibody levels, and periodontitis disease recurrence

BACKGROUND AND OBJECTIVE

The biological and clinical effects of antibody against periodontal pathogenic bacteria are incompletely understood. This study evaluated the inter-relationships among periodontal levels of cultivable Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis, species-specific serum immunoglobulin G (IgG) antibody levels, and periodontitis disease activity.

MATERIAL AND METHODS

Forty-three adults who had previously been treated for periodontitis and who also harbored cultivable A. actinomycetemcomitans or P. gingivalis were evaluated semiannually for clinical disease recurrence over a 36-month period. Each patient provided subgingival microbial samples, for the recovery of A. actinomycetemcomitans and P. gingivalis, from the two deepest pockets in each dentition sextant. A. actinomycetemcomitans and P. gingivalis serum IgG antibody levels were assessed using enzyme-linked immunosorbent assay (ELISA), together with whole-cell sonicate extracts from A. actinomycetemcomitans serotypes a-c and P. gingivalis ATCC 33277. Data were analyzed using the Mantel-Haenszel chi-square and Fisher exact two-tailed tests.

RESULTS

Eighteen (60.0%) of 30 A. actinomycetemcomitans-positive subjects, and 10 (76.9%) of 13 P. gingivalis-positive subjects, exhibited recurrent periodontal breakdown within 36 months of periodontal therapy. Nineteen (67.9%) of the 28 patients with active periodontitis had A. actinomycetemcomitans or P. gingivalis serum antibody levels below designated threshold values. In comparison, 10 (66.7%) of 15 culture-positive clinically stable subjects showed A. actinomycetemcomitans or P. gingivalis serum antibody levels above threshold values. The difference between specific antibody levels in periodontitis-active and periodontitis-stable patients was statistically significant (p = 0.032).

CONCLUSIONS

Serum levels of IgG antibodies against A. actinomycetemcomitans or P. gingivalis in periodontitis-stable patients were higher than those in patients with active periodontitis. The results suggest that elevated levels of IgG antibody against A. actinomycetemcomitans and P. gingivalis have a detectable protective effect against periodontal infections with these microorganisms.

Identification of oral bacteria associated with crevicular epithelial cells from chronic periodontitis lesions

Bacterial invasion of host epithelial cells plays an important role in the pathogenesis of periodontal diseases; however, the interactions between subgingival species and the gingival crevice cells are not fully understood. This study determined the prevalence of a group of oral bacterial species on or in epithelial cells derived from periodontal pockets and the gingival crevice of subjects with periodontitis. Samples of epithelial cells were obtained from 120 sites with periodontal pockets > or =4 mm and 92 periodontally healthy sites from 49 patients (mean age 46.3+/-1.4 years; 43% males) with chronic periodontitis. Bacteria in or on epithelial cells were separated from unattached bacteria by Percoll density-gradient centrifugation. The presence and levels of 33 oral species were determined in epithelial cell samples by whole genomic DNA probes and the checkerboard method. The most frequently detected species were Porphyromonas gingivalis (42%), Treponema denticola (38%), Prevotella intermedia (37%), Streptococcus intermedius (36%), Campylobacter rectus (35%), Streptococcus sanguinis (35%) and Streptococcus oralis (34%). Species of Actinomyces were found in low prevalence and levels. The data indicated that there were more micro-organisms on or in epithelial cells obtained from periodontal pockets than from healthy sulci; however, no significant differences regarding the percentage and level of any specific species were found between these sites. Veillonella parvula, S. oralis, Streptococcus gordonii and Streptococcus mitis tended to be more prevalent in sites without disease. These findings demonstrated that a wide range of oral species may be detected on or in crevicular epithelial cells from sites with periodontitis and from periodontally healthy sulci.

Increase in probing depth is correlated with a higher number of Prevotella intermedia genotypes

BACKGROUND

The aims of this study were to determine the genotypic diversity of Prevotella intermedia in subgingival plaque samples by using two techniques, arbitrarily primed polymerase chain reaction (AP-PCR) and heteroduplex analysis, and to assess the relationship of this diversity with increase in probing depth.

METHODS

The subgingival plaque samples were obtained from 12 patients using paper points inserted into periodontal pockets (diseased sites) and healthy gingival sulci (healthy sites) of the same subjects. After isolation and identification, AP-PCR was performed for genotypic characterization of P. intermedia (80 isolates). The clinical samples with a positive result for P. intermedia were amplified by 16S rRNA-based PCR method, and the amplicons were subjected to heteroduplex analysis.

RESULTS

The agreement between the two methods was very high; the AP-PCR and heteroduplex analysis showed that subjects harbored between one and five distinct genotypes of P. intermedia, with a positive association between numbers of genotypes by AP-PCR (P = 0.0042) or heteroduplex (P = 0.0099) and increase in probing depth. No matching of P. intermedia genotypes was observed between healthy and diseased sites of the same individual. Interindividual analyses demonstrated absence of identical clones and indicated a high level of genetic diversity in the species.

CONCLUSION

A clear relationship was observed between a higher number of genotypes and increase in probing depth; these results suggest that environmental challenges in the periodontal pockets may modulate the microbiota by selecting genotypes best able to exploit the environment.

Short-term clinical and microbiologic effects of pocket debridement with an Er:YAG laser during periodontal maintenance

BACKGROUND

The erbium-doped:yttrium, aluminum, and garnet (Er:YAG) laser is considered a useful tool for subgingival debridement because the laser treatment creates minimal damage to the root surface and has potential antimicrobial effects. The aim of this randomized controlled clinical trial was to evaluate clinical and microbiologic effects of pocket debridement using an Er:YAG laser in patients during periodontal maintenance.

METHODS

Twenty patients at a recall visit for maintenance were consecutively recruited if presenting at least four teeth with residual probing depth (PD) > or = 5 mm. Two pockets in each of two jaw quadrants were randomly assigned to subgingival debridement using 1) an Er:YAG laser (test) or 2) an ultrasonic scaler (control). The laser beam was set at 160 mJ with a pulse frequency of 10 Hz. Clinical variables were recorded at baseline, 1 month, and 4 months after treatment. Primary clinical outcome variables were changes in PD and clinical attachment level (CAL). Microbiologic analysis of subgingival samples was performed at baseline, 2 days, and 30 days after treatment using a checkerboard DNA-DNA hybridization technique against 12 periodontal disease-associated species.

RESULTS

The mean initial PD was 6.0 mm (SD: 1.2) in the test group and 5.8 mm (SD: 0.9) in the control group. At 1 month post-treatment, the PD reduction was significantly greater for test than control sites (0.9 versus 0.5 mm; P <0.05). The CAL gain also was significantly greater (0.5 versus 0.06 mm; P <0.01). At the 4-month examination, no significant differences were detected in PD reduction (1.1 versus 1.0 mm) or CAL gain (0.6 versus 0.4 mm). Both treatments resulted in reduction of the subgingival microflora. No significant differences in microbiologic composition were identified between the treatment groups at various time intervals. Degree of treatment discomfort scored significantly lower for the test than the control treatment modality.

CONCLUSION

The results of the trial failed to demonstrate any apparent advantage of using an Er:YAG laser for subgingival debridement, except less treatment discomfort perceived by the patients.

A new checkerboard panel for testing bacterial markers in periodontal disease

BACKGROUND/AIMS

Various microbiological methods have been used for testing bacterial markers for periodontitis and periodontal disease progression. Most studies have used only a limited number of well recognized bacterial species. The purpose of the present study was to evaluate the association of 13 more recently identified bacterial species in a new panel in comparison with 12 previously more recognized periodontotopathogens ('old panel') using the 'checkerboard' DNA-DNA hybridization method.

METHODS

Fifty individuals were chosen who showed at least one site with a probing pocket depth of 6 mm or more (disease) and bleeding on probing and at least one site with a probing pocket depth of 3 mm and without bleeding on probing (health). One diseased and one healthy site on each individual were sampled with the paperpoint technique and the samples were processed in the checkerboard technique against deoxigenin-labeled whole genomic probes to 25 subgingival species representing 12 well recognized and 13 newly identified periodontitis associated species.

RESULTS

Twenty-four (out of 25) species were detected more frequently in the subgingival plaque of diseased than healthy sites both at score 1 (> 10(4)) and score 3 (> 10(5)). A significant difference at the higher score (score 3) was noticed for all species of the old panel except for three (Streptococcus intermedius, Selenomonas noxia, and Eikenella corrodens). Of the species in the new panel only Prevotella tannerae, Filifactor alocis, and Porphyromonas endodontalis showed a statistical significant difference between diseased and healthy sites.

CONCLUSION

It was concluded that P. tannerae, F. alocis, and P. endodontalis should be added to the 12 species used for routine diagnostics of periodontitis-associated bacterial flora.

Effect of a Controlled-Release Chlorhexidine Chip on Clinical and Microbiological Parameters and Prostaglandin E2Levels in Gingival Crevicular Fluid

BACKGROUND

The aim of the present study was to determine the effect of a chlorhexidine chip on crevicular prostaglandin E2 (PGE2) levels and on the clinical and microbiological parameters of periodontitis when used as adjunctive therapy to scaling and root planing (SRP) in patients with chronic periodontitis.

METHODS

This randomized single-blind study was carried out in parallel design. The test group received SRP plus chlorhexidine chip, whereas the control group received SRP alone. Thirty-four subjects, aged 20 to 55 years, with chronic periodontitis were recruited. Clinical indices, microbiological samples, and gingival crevicular fluid (GCF) samples were evaluated at baseline and after 1, 3, and 6 months. Microbiological samples were evaluated under a light microscope. GCF PGE2 levels were determined using radioimmunoassay.

RESULTS

Significant improvements could be found for all clinical variables in both groups over the study period. The mean changes in probing depth obtained by SRP plus chlorhexidine chip were greater than those obtained by the SRP alone group at 3 and 6 months. In the test group, there was also significant gain in clinical attachment level at 6 months. When data were combined from all groups, significant reductions in GCF PGE2 levels and number of microorganisms were noted at all time points. However, in the test group, reduction was greater at 6 months for crevicular PGE2 level and at 3 and 6 months for proportions of spirochetes.

CONCLUSION

Based on the findings of this study, the chlorhexidine chip reduced GCF PGE2 levels and had positive effects on clinical parameters and subgingival flora when used as adjunctive therapy to SRP in patients with chronic periodontitis.

Supportive periodontal therapy using mechanical instrumentation or 2% minocycline gel: a 12 month randomized, controlled, single masked pilot study

OBJECTIVE

To compare the short-term performance of subgingival local delivery of 2% minocycline gel and conventional subgingival debridement in supportive periodontal therapy (SPT) patients.

METHODS

Forty adult patients having completed active treatment for moderate to advanced chronic periodontitis were included in a randomized, controlled, single masked maintenance care pilot study. Sites with residual pocket probing depths > or =5 mm and bleeding on probing were treated with either minocycline gel (minocycline-group) or scaling and root planing only (debridement-group) at baseline, 3, 6, and 9 months. Clinical and microbiological examinations were performed at baseline, 3, 6, 9, and 12 months.

RESULTS

Full-mouth plaque and bleeding scores remained <10% and <20%, respectively, for both groups throughout the study. In both groups there was a persistent reduction in number of teeth and sites with probing pocket depths > or =5 mm (p<0.05) with no significant differences between the groups. The prevalence of Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Actinobacillus actinomycetemcomitans, Prevotella intermedia, and Prevotella nigrescens, remained at levels < or =10(5) in the majority of patients and sites in both groups.

CONCLUSION

This pilot study failed to show a difference between local delivery of 2% minocycline gel as mono-therapy and traditional subgingival debridement in patients on SPT.

Asaccharolytic anaerobic gram-negative coccobacilli (AAGNC) isolated from infected root canals and periodontal pockets

BACKGROUND/AIMS

Culture-difficult bacteria, including asaccharolytic anaerobic gram-negative coccobacilli (AAGNC), may constitute a predominant group of organisms in oral sites. This study aimed to characterize phylogenetically 10 AAGNC isolated from endodontic lesions and periodontal pockets.

METHODS

16S rDNA sequence and G + C content were determined. Strains sharing more than 98% sequence similarities and similar G + C content were considered the same bacterial species.

RESULTS

One isolate resembled Dialister pneumosintes (the type species of the genus Dialister) with 35 mol% G + C content and 97% sequence similarity. Of eight isolates having 45-47 mol% G + C content, seven were identified as D. invisus and one resembled Dialister invisus with 97% sequence similarity. However the 16S rDNA sequence similarities with D. pneumosintes were relatively low, indicating the strains may belong to a new genus. The last isolate revealed 35 mol% G + C content, but had higher 16S rDNA sequence similarity with D. invisus than with D. pneumosintes.

CONCLUSION

The group of oral AAGNC isolates need to be reclassified.

Microbial colonization patterns predict the outcomes of surgical treatment of intrabony defects

AIM

To explore the impact of bacterial load and microbial colonization patterns on the clinical outcomes of periodontal surgery at deep intrabony defects.

MATERIALS AND METHODS

One hundred and twenty-two patients with advanced chronic periodontitis and at least one intrabony defect of >3 mm were recruited in 10 centres. Before recruitment, the infection control phase of periodontal therapy was completed. After surgical access and debridement, the regenerative material was applied in the test subjects, and omitted in the controls. At baseline and 1 year following the interventions, clinical attachment levels (CAL), pocket probing depths (PPD), recession (REC), full-mouth plaque scores and full-mouth bleeding scores were assessed. Microbial colonization of the defect-associated pocket was assessed using a DNA-DNA checkerboard analysis.

RESULTS

Total bacterial load and counts of red complex bacteria were negatively associated with CAL gains 1 year following treatment. The probability of achieving above median CAL gains (>3 mm) was significantly decreased by higher total bacterial counts, higher red complex and T. forsythensis counts immediately before surgery.

CONCLUSIONS

Presence of high bacterial load and specific periodontal pathogen complexes in deep periodontal pockets associated with intrabony defects had a significant negative impact on the 1 year outcome of surgical/regenerative treatment.

Clinical state of the patients with periodontitis, IL-1 polymorphism and pathogens in periodontal pocket--is there a link? (An introductory report)

PURPOSE

According to last years' research, polymorphism of IL-1 has an influence on the progression of periodontal disease. Oral mouth microflora can also have an effect on the disease process. The aim of the work was to evaluate the amount of microbacterial pathogens in the periodontal pockets of patients with positive and negative genotype.

MATERIAL AND METHODS

Study group comprised of 16 patients, aged 25-50 years. Only patients with severe generalized form of chronic periodontititis were included into the study. After clinical examination patients were subjected to the IL-1 genotype evaluation (Genotype PST, Hain Lifescience GmbH, Germany) and PCR examination of selected bacteria pathological for periodontium (Perio-Analyse, Pierre Fabre Medicament, France).

RESULTS

7 out of 16 individuals were diagnosed as genotype positive (alleles 2 for genes IL-1A and IL-1B). Genetically positive individuals had greater mean pocket depth, clinical attachment loss and percentage of pockets deeper than 4 mm. Although in both groups similar bacterial pathogens have been identified, greater amounts of bacteria have been counted in group with positive genotype. Total count of bacteria from so-called "red complex" (P. gingivalis, T. forsythensis, T. denticola), and "orange complex" (F. nucleatum, P. micros, P. intermedia, C. rectus) were respectively 3-fold and 2-fold higher in group with positive genotype, despite the fact that group was smaller (7 vs 9 persons with negative genotype). Number and species of bacteria seems to correlate with pocket depth, clinical attachment loss, and percentage of pockets deeper than 4 mm.

CONCLUSION

Observed association may have an influence on increased severity of periodontal disease in patients with positive genotype.

Local Oxygen Therapy for Treating Acute Necrotizing Periodontal Disease in Smokers

BACKGROUND

The main aim of treatment for acute necrotizing periodontal disease is fast and effective reduction of anaerobic destructive microorganisms to avoid periodontal damage. The effect of adjunctive local oxygen therapy in the treatment of necrotizing periodontal disease was examined in this study.

METHODS

Thirty patients with acute necrotizing periodontal disease were treated with the systemic antibiotics amoxicillin, clavulanic acid, and metronidazole. In 15 out of 30 patients, adjunctive local oxygen therapy was administered. The patients were followed from the first to 10th day of treatment with clinical and bacteriological examinations. The clinical examination registered gingival bleeding, periodontal probing depth, and attachment loss; to follow up microbiological colonization of the periodontal sulcus, five representative bacteria were registered by a semiquantitative DNA polymerase chain reaction test.

RESULTS

In both groups of patients, colonization with Prevotella intermedia, Tannerella forsythensis, and Treponema denticola was initially positive. None of these three microorganisms were completely eradicated in any of the patients in the group without oxygen therapy within the first 10 days of treatment. In the group with adjunctive oxygen therapy, all patients either showed a reduction in or complete eradication of the microorganisms, resulting in more rapid clinical restitution with less periodontal destruction.

CONCLUSIONS

Adjunctive oxygen therapy results in early eradication of pathogenic anaerobic microorganisms in cases of acute necrotizing periodontal disease. The damage to periodontal tissue is reduced.

Immediate effect of instrumentation on the subgingival microflora in deep inflamed pockets under strict plaque control

OBJECTIVE

To investigate (1) reduction in the number of microorganisms obtained directly after subgingival instrumentation, (2) rate of bacterial re-colonization during 2 weeks, under supragingival plaque-free conditions.

MATERIALS AND METHODS

Effects of subgingival instrumentation were measured at one deep pocket in 22 patients (11 smokers and 11 non-smokers). Immediately after initial therapy, experimental sites, under strict plaque control, were instrumented subgingivally. Microbiological evaluation was performed at pre-instrumentation, immediate post-instrumentation and 1 and 2 weeks post-instrumentation.

RESULTS

Mean total anaerobic colony forming units (CFUs) dropped from 3.9 x 10(6) before to 0.09 x 10(6) immediately following instrumentation. Significant reductions were found for Tannerella forsythia, Micromonas micros, Fusobacterium nucleatum and spirochetes. Significant reductions were not observed for Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia and Campylobacter rectus. Except for spirochetes, no reduction in prevalence of specific periodontal bacteria was found immediately after instrumentation. During follow-up, mean total CFU tended to increase. Prevalence of periodontal bacteria further reduced. No effect of smoking was found.

CONCLUSION

Results indicate that subgingival mechanical cleaning in itself, has a limited effect, in actually removing bacteria. The subsequent reduction in prevalence of specific periodontal bacteria shows that it is apparently difficult for these species to survive in treated pockets.

Periodontitis as a risk factor of coronary heart diseases?

BACKGROUND

Unstable atherosclerotic plaque is a dangerous clinical state, possibly leading to acute coronary deficiency resulting in cardiac infarction. Inflammatory factor's role in creating pathological lesions in the endothelium of coronary vessels is frequently raised. This state may be caused by bacteria able to initiate clot formation in blood vessel and destabilizing atherosclerotic plaque already present. Source of these pathogens are chronic inflammatory processes occurring in organism, among them periodontal disease as one of more frequent. Aim of the work was to evaluate incidence of selected anaerobic bacteria in subgingival plaque and in atherosclerotic plaque in patients treated surgically because of coronary vessels' obliteration.

METHODS

Study was performed on 20 individuals with chronic periodontitis. Subgingival plaque was collected from periodontal pockets deeper than 5 mm DNA test was used for marking eight pathogens responsible for periodontal tissues destruction. In the same patients, as well as in 10 edentulous individuals material from atherosclerotic plaque was collected during by-pass implantation procedure, and identical DNA testing occurred.

RESULTS

In 13 of 20 patients pathogens most frequent in severe chronic periodontitis were found in coronary vessels. In 10 cases those bacteria were also present in atherosclerotic plaque. Pathogens linked with periodontal disease were also found in 7 of 10 edentulous individuals. Most frequently marked bacteria were: Porphyromonas gingivalis and Treponema denticola.

CONCLUSIONS

It seems that advancement of periodontal disease does not have influence on bacteria permeability to coronary vessels. Important is the presence of active inflammatory process expressed by significantly higher bleeding index in patients with marked bacteria in atherosclerotic plaque.

Cytomegalovirus-Associated Periodontitis and Guillain-Barré Syndrome

BACKGROUND

Guillain-Barré syndrome (GBS), an autoimmune disorder of the peripheral nervous system, is characterized by rapidly ascending neural paralysis, hyporeflexia, and areflexia. The polyneuropathy of the GBS affects one to four humans per 100,000 of the population annually throughout the world (adults and children). The pathogenesis of GBS remains unclear. However, there are increasing indications that the disease is triggered by a preceding well-established febrile infection by cytomegalovirus (CMV). The present report describes active CMV within the periodontium of a 37-year-old patient affected by GBS.

METHODS

Real-time reverse transcriptase-polymerase chain reaction (real-time RT-PCR) was performed to detect CMV, Epstein-Barr virus-1 (EBV-1), herpes simplex 1 (HSV-1) and 2 (HSV-2) virus, and enteroviruses (polio-, coxsackie-, echo-, and enteroviruses 68 and 71) from periodontal sites demonstrating advanced attachment loss. Healthy sites and sites with inflamed gingival tissue were not included in the study. Anaerobic bacterial culture determined the occurrence of potential major periodontal pathogens.

RESULTS

Real-time RT-PCR and microbiologic analysis revealed the presence of a dual infection of CMV and specific bacterial plaque. CMV, Porphyromonas gingivalis, Tannerella forsythensis, and Campylobacter species were associated with periodontitis active sites, loss of attachment, and gingival bleeding. Furthermore, periodontal sites infected by active CMV had no visible radiographic crestal lamina dura.

CONCLUSIONS

The periodontium may serve as a reservoir for CMV and a source of viral replication. However, further research is needed to test whether viral replication in the periodontium precedes the GBS symptoms.

Genetic relatedness of oral yeasts within and between patients with marginal periodontitis and subjects with oral health

BACKGROUND

Yeasts are found in periodontal pockets at a frequency of 15-21%. However, the genetic relatedness of oral yeasts within and between patients with marginal periodontitis is not clear.

OBJECTIVES

Assay genetic relatedness of oral yeasts from marginal periodontitis patients and oral health subjects, as well as genetic relatedness of yeasts from different oral sites in these two groups of participants.

MATERIAL AND METHODS

Yeast isolates were collected from 23 marginal periodontitis patients and 19 oral health subjects. Random amplified polymorphic DNA (RAPD) fingerprinting and the Dendron computer-assisted program for gel analyses were applied for estimation of genetic relatedness of yeasts.

RESULTS

The similarity coefficient (S(AB)) of the marginal periodontitis group ranged from 0.49 to 1.00 with an average of 0.64 +/- 0.11, whereas the S(AB) of the oral health group ranged from 0.62 to 1.00 with an average of 0.72 +/- 0.07. Three genetic clusters and 73 genotypes were obtained from the marginal periodontitis group, whereas three genetic clusters and 55 genotypes were found in the oral health group. In the pooled dendrogram, 57% of the yeast isolates and the type strain of Candida albicans fell in a major cluster V. There were no significant differences between the frequencies of clusters from the different oral sites within the two participant groups.

CONCLUSIONS

Genetically heterogeneous yeasts were found in the oral cavities of marginal periodontitis patients and oral health subjects. Similar genetic clustering patterns were obtained from the yeasts of the two groups, with cluster V being most predominant. Yeasts of the marginal periodontitis group were more genetically diverse than yeasts of the oral health group, and some yeasts of the marginal periodontitis group exhibited unique genetic patterns. There was no clear association between yeast genetic clusters and oral sites in the two participant groups.

The distribution ofTannerella forsythiain an adolescent and adult population

BACKGROUND

The fact that Tannerella forsythia, an important periopathogen, is difficult to cultivate from mixed infections has impeded precise estimates of its distribution within a given population. In order to discern T. forsythia alone from the mixed infection of plaque, the use of sensitive 16S ribosomal RNA based polymerase chain reaction (PCR) detection is necessary.

OBJECTIVES

The aim of the present study was to determine the distribution of T. forsythia in an adult and in an adolescent population.

MATERIAL AND METHODS

Subgingival plaque samples were obtained from 498 Australian adults and from 228 adolescent subjects from Manchester, UK. Tannerella forsythia was detected using PCR and confirmed by restriction analysis. Semi-quantitation of the organisms was carried out using two specific primers of differing sensitivities.

RESULTS

In the adolescent population, 25% were found to carry T. forsythia, albeit in relatively low numbers. In the adult population, a total of 37.8% and 11% were found to carry the organism with primer 2 and primer 1, respectively, suggesting that around 27% had between 10(3) and 10(7) organisms. Although there was an apparent increased proportion of T. forsythia positive subjects in those aged > or = 50 years, this was not statistical significant. However, T. forsythia positive male smokers showed increased disease severity compared with T. forsythia negative subjects.

CONCLUSION

This study has shown that at least 25% of the adolescent population carry low numbers of T. forsythia, whereas at least 37% of adults carry the organism, with some 11% having relatively high numbers. The relationship between T. forsythia and disease progression in these populations, however, remains to be determined.

Comparisons of bacterial patterns present at implant and tooth sites in subjects on supportive periodontal therapy

OBJECTIVE

(I) To compare the oral microflora at implant and tooth sites in subjects participating in a periodontal recall program, (II) to test whether the microflora at implant and tooth sites differ as an effect of gingival bleeding (bleeding on probing (BOP)), or pocket probing depth (PPD), and (III) to test whether smoking and gender had an impact on the microflora.

MATERIAL AND METHODS

Data were collected from 127 implants and all teeth in 56 subjects. Microbiological data were identified by the DNA-DNA checkerboard hybridization.

RESULTS

PPD> or =4 mm were found in 16.9% of tooth, and at 26.6% of implant sites (P<0.01). Tooth sites with PPD> or =4 mm had a 3.1-fold higher bacterial load than implant sites (mean difference: 66%, 95% confidence interval (CI): 40.7-91.3, P<0.001). No differences were found for the red, orange, green, and yellow complexes. A higher total bacterial load was found at implant sites with PPD> or =4 mm (mean difference 35.7 x 10(5), 95% CI: 5.2 (10(5)) to 66.1 (10(5)), P<0.02 with equal variance not assumed). At implant sites, BOP had no impact on bacterial load but influenced the load at tooth sites (P<0.01).

CONCLUSION

BOP, and smoking had no impact on bacteria at implant sites but influenced the bacterial load at tooth sites. Tooth sites harbored more bacteria than implant sites with comparable PPD. The 4 mm PPD cutoff level influenced the distribution and amounts of bacterial loads. The subject factor is explanatory to bacterial load at both tooth and implant sites.

Dynamics of initial subgingival colonization of ‘pristine’ peri-implant pockets

BACKGROUND

Periodontitis and peri-implantitis are linked to the presence of several key pathogens. The treatment of these infectious processes therefore involves the reduction/eradication of bacteria associated with periodontitis.

METHODS

This prospective, split-mouth, single-blind study followed the colonization of 'pristine' sulci created in 42 partially edentulous patients during implant surgery (e.g. abutment connection). The hypothesis was that the composition of the maturing subgingival plaque in these 'fresh' peri-implant pockets would soon (within 2 weeks) be comparable to the subgingival microbiota of teeth with similar clinical parameters (reference sites), including the presence of bacteria associated with periodontitis. Per patient, four subgingival plaque samples were taken from shallow and medium pockets around implants (test sites), and teeth within the same quadrant (undisturbed microbiota as control sites), 1, 2, 4, 13, 26 and 78 weeks after abutment connection, respectively. The samples were analysed by either checkerboard DNA-DNA hybridization, or cultural techniques, or real-time polymerase chain reaction (PCR) for intra-subject comparisons (teeth vs. implant, for comparable probing depths).

RESULTS

Checkerboard DNA-DNA hybridization and real-time PCR revealed a complex microbiota (including several pathogenic species) in the peri-implant pockets within 2 weeks after abutment connection. After 7 days, the detection frequency for most species (including the bacteria associated with periodontitis) was already nearly identical in samples from the fresh peri-implant pockets (5% and 20% of the microbiota belonging to red and orange complex, respectively) when compared with samples from the reference teeth. Afterwards (e.g. between weeks 2 and 13), the number of bacteria in peri-implant pockets only slightly increased (+/-0.1 log value), with minor changes in the relative proportions of bacteria associated with periodontitis (8% and 33% of the microbiota belonging to red and orange complex, respectively). Although small differences were seen between teeth and implants at week 2 with cultural techniques, a striking similarity in subgingival microbiota was found with this technique from month 3 on, with nearly identical detection frequencies for bacteria associated with periodontitis for both abutment types.

CONCLUSIONS

This study indicates that the initial colonization of peri-implant pockets with bacteria associated with periodontitis occurs within 2 weeks.

Effects of topical application of metronidazole-containing mucoadhesive lipogel in periodontal pockets

INTRODUCTION

Metronidazole is the drug of choice in the treatment of periodontal pockets up to 5 mm in depth. It is topically applied--directly into the periodontal pockets. There are no registred trademark preparations for this purpose in the market of Serbia and Montenegro. The aim of our latest research was to test the efficacy of newly formulated preparation containing 25% metronidazole suspended in a lipogel in vitro--in anaerobic cultures isolated from the periodontal pockets, and in vivo--by the direct application into periodontal pockets.

METHODS

Preparation efficacy was tested in a randomized controlled study involving 25 patients, and was confirmed by the membrane-free agar diffusion method on the anaerobic strains isolated from the periodontal pockets. The duration of the testing was 30 days. The preparation was applied twice--immediately after the taking of the first swab, and on day 15, when the control swab was taken for the assessment of the effects of the applied preparation.

RESULTS

Seven anaerobic strains were isolated and tested, and each was confirmed as highly susceptible to metronidazole. Anaerobic strains were not isolated in any of the pockets treated with metronidazole-containing lipogel. The strains isolated in the control pockets were the same as were those at the beginning of the study.

CONCLUSION

Metronidazole, in a lipogel-type base applied in the concentration of 25%, provided an efficient treatment of anaerobic infection in the periodontal pockets.

Initial subgingival colonization of 'pristine' pockets

The treatment of periodontitis/peri-implantitis involves the reduction/eradication of periopathogens. After therapy, beneficial and pathogenic species recolonize the subgingival area. The dynamics of recolonization and especially the role of the supragingival environment in this process are still not well-understood. This prospective, split-mouth study followed the early colonization of 'pristine' pockets created during implant surgery (16 partially edentulous patients), to record the time needed before a complex subgingival flora could be established with the supragingival area as the single source. Four subgingival plaque samples were taken from shallow and medium pockets around implants (test), and neighboring teeth (undisturbed microbiota as reference) 1, 2, and 4 wks after abutment connection. Checkerboard DNA-DNA hybridization and culture data revealed a complex microbiota (including several pathogenic species) in the pristine pockets within a wk, with a minimal increase in counts up to 4 wks. Analysis of these data demonstrated that, even with the supragingival environment as the single source for colonizing bacteria, a complex subgingival microbiota can develop within 1 wk.

Differential induction of human beta-defensin expression by periodontal commensals and pathogens in periodontal pocket epithelial cells

BACKGROUND

To investigate the possible role of beta-defensins in gingival health and periodontal disease, we examined the effect of several stimuli on the expression of interleukin-8 (IL-8), human beta-defensin-1, -2, -3, and -4 (hBD) in primary human diseased gingival epithelial (HGE) cell cultures from periodontitis patients by quantitative TaqMan reverse transcription polymerase chain reaction (RT-PCR).

METHODS

Several strains of the periodontopathogens Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis were added to the cells, as well as the oral commensal bacteria Fusobacterium nucleatum and Escherichia coli. The induction by the proinflammatory stimuli phorbol 12-myristate 13-acetate (PMA) and tumor necrosis factor-alpha (TNF-alpha) was also tested.

RESULTS

In addition to the published observations (PMA induces hBD-2 and -4; TNF-alpha induces hBD-2 and -3), it was found that PMA can upregulate hBD-1 and hBD-3, whereas TNF-alpha can induce hBD-4. The commensal bacteria were significant inducers of hBD-2, hBD-3, and IL-8. The pathogen P. gingivalis induced hBD-1 and hBD-3 at different time points than the commensals, but no induction of IL-8 and hBD-2 could be observed. These data fit with the chemokine paralysis theory. A correlation was found between the pathogenicity of different serotypes of A. actinomycetemcomitans and the induction profiles of defensins and IL-8.

CONCLUSION

The results suggest that a correlation can be found in diseased oral epithelium between the defensin profiles that are induced and the pathogenicity of the oral bacterial strains.

Cross-reactivity of GroEL antibodies with human heat shock protein 60 and quantification of pathogens in atherosclerosis

BACKGROUND/AIMS

Chronic infections such as those caused by Chlamydia pneumoniae and periodontopathic bacteria such as Porphyromonas gingivalis have been associated with atherosclerosis, possibly due to cross-reactivity of the immune response to bacterial GroEL with human heat shock protein (hHSP) 60.

METHODS

We examined the cross-reactivity of anti-GroEL and anti-P. gingivalis antibodies with hHSP60 in atherosclerosis patients and quantified a panel of six pathogens in atheromas.

RESULTS

After absorption of plasma samples with hHSP60, there were variable reductions in the levels of anti-GroEL and anti-P. gingivalis antibodies, suggesting that these antibodies cross-reacted with hHSP60. All of the artery specimens were positive for P. gingivalis. Fusobacterium nucleatum, Tannerella forsythia, C. pneumoniae, Helicobacter pylori, and Haemophilus influenzae were found in 84%, 48%, 28%, 4%, and 4% of arteries, respectively. The prevalence of the three periodontopathic microorganisms, P. gingivalis, F. nucleatum and T. forsythia, was significantly higher than that of the remaining three microorganisms.

CONCLUSIONS

These results support the hypothesis that in some patients, cross-reactivity of the immune response to bacterial HSPs including those of periodontal pathogens, with arterial endothelial cells expressing hHSP60 may be a possible mechanism for the association between atherosclerosis and periodontal infection.

Bacterial internalization in periodontitis

BACKGROUND

Bacterial invasion of host epithelial cells plays an important role in the pathogenesis of periodontitis; however, the exact mechanism of the invasion has not been investigated.

METHODS

Pocket epithelium biopsies in periodontitis were analysed via scanning and transmission electron microscopy using ultra-histochemical staining with ruthenium red for glycocalyx visualization.

RESULTS

We demonstrated that oral bacteria adhered via fimbriae-mediated adhesion only. The bacterial internalization in periodontitis was marked by the hallmark of the fimbriae-induced zipper mechanism--the phagocytic cup formation--but we found no sign of the trigger mechanism of internalization. In addition, we frequently observed apoptosis in the phagocytizing epithelial cells.

CONCLUSION

Fimbriae-mediated adhesion is a prerequisite for bacterial invasion in periodontitis. This occurs by the fimbriae-induced zipper mechanism of internalization. As internalization induces apoptosis, the subsequent exfoliation might play a significant role in the clearance of periodontal pathogens.

Comparison of culture and real-time PCR for detection and quantification of five putative periodontopathogenic bacteria in subgingival plaque samples

OBJECTIVES

Bacterial cultivation is a well-established method for analyzing plaque samples. Real-time polymerase chain reaction (PCR) is a novel rapid method for the identification and quantification of periodontopathogenic bacteria that has been recently introduced. In this study, we compared real-time PCR with conventional anaerobic cultivation.

METHOD

A total of 78 subgingival plaque samples were harvested from pockets > or =5 mm in 22 patients with advanced chronic periodontitis and immediately transferred into transport medium. Aliquots were evaluated with species-specific probes by real-time PCR (meridol Perio Diagnostics, GABA) and anaerobic bacteria culture on selective media for the detection of Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia and Tannerella forsythensis. The analysis was performed by two separate, blinded examiners.

RESULTS

When real-time PCR was compared with the culture method (golden standard) for the detection of putative periodontopathogenic bacteria, the sensitivity and specificity for A. actinomycetemcomitans were 67% and 100%, respectively (kappa: 0.79); for F. nucleatum 73% and 53%, respectively (kappa: 0.21); for P. gingivalis 94% and 84%, respectively (kappa: 0.77); for P. intermedia 33% and 94%, respectively (kappa: 0.26) and for T. forsythensis 92% and 56%, respectively (kappa: 0.51). Spearman's correlation coefficients for the quantitative results of both methods were 0.82 for A. actinomycetemcomitans, 0.33 for F. nucleatum, 0.83 for P. gingivalis, 0.38 for P. intermedia and 0.67 for T. forsythensis.

CONCLUSION

Overall, the agreement between both test methods was excellent for A. actinomycetemcomitans and P. gingivalis, fair for T. forsythensis and poor for F. nucleatum and P. intermedia. The discrepancies in the results may be explained by the inability of cultivation methods to distinguish between close related taxa, and the problems of keeping periopathogenic bacteria viable, which is required for standard cultivation.

Surface morphology of pocket epithelium

The pocket epithelium in periodontitis differs from the clinically healthy epithelium in its increase in sulcular depth. However, closer surface morphological distinctions have not been described. To study the surface characteristics of pocket gingiva, the authors analyzed pocket and sulcular epithelium biopsies by scanning and transmission electron microscopy using cytochemical staining for visualization of bacterial adhesion. The clinically healthy and the marginal pocket epithelium were characterized by squamous epithelial cells joined by tight junctions and an inconspicuous surface lacking a distinctive papillary formation. The large quantity of bacteria that adhered to the clinically healthy and marginal pocket epithelium did not appear to elicit any significant defense response. The deeper part of the pocket epithelium revealed a wrinkled papillary relief, increased exfoliation of epithelial cells, leukocyte transmigration, and bacterial internalization, as well as internalization-induced epithelial apoptosis. The alteration of the deep pocket epithelium surface might be either genuine or due to environmental changes of the crevice, or both. Therefore, the periodontitis recovery after removing the deep pocket epithelium might now be related to the pathological alterations of the deep pocket epithelium.

Predictive value of clinical and microbiological parameters for the treatment outcome of scaling and root planing

OBJECTIVES

To compare the clinical and microbiological outcome of non-surgical periodontal therapy after 6 months with data obtained after hygienic phase or 6 weeks after completion of non-surgical therapy, in order to evaluate the value of clinical and microbiological parameters to predict treatment success.

MATERIAL AND METHODS

Clinical and microbiological data were available from 271 sites in 10 systemically healthy non-smokers with moderate-to-advanced chronic periodontal disease (24-32 sites per individual). Subgingival plaque samples were tested for the presence of Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Tannerella forsythensis and Treponema denticola using RNA probes.

RESULTS

Stepwise multiple linear regression analysis revealed a significant impact of the number of sites with visible plaque index >1 after hygienic phase on the bleeding tendency of a subject at month 6 (p<0.01). Furthermore, an association could be demonstrated between the number of residual pockets (PD>3 mm) 6 months after therapy and the number of bleeding sites and suppurating sites after hygienic phase (p=0.016). Six weeks after therapy, the mean total bacterial loads had a significant impact on the bleeding tendency of a subject at month 6 (p<0.01). Although the average numbers of sites with persisting P. gingivalis, A. actinomycetemcomitans, T. forsythensis and T. denticola seemed to be very similar 6 weeks and 6 months after therapy, large variations were noted between subjects, and therefore the microbiological status of a subject at week 6 could not predict the status at month 6.

CONCLUSIONS

The present study showed a limited potential of microbiological tests, performed after hygienic phase or shortly after non-surgical periodontal therapy, to predict the clinical outcome 6 months later, but confirmed the importance of an establishment of perfect oral hygiene before non-surgical therapy.

Subgingival distribution of Campylobacter rectus and Tannerella forsythensis in healthy children with primary dentition

OBJECTIVE

It is important to know how many subgingival plaque samples should be assayed from a child to ascertain infection with a periodontal pathogen. Plaque samples from several sites may fail to detect some important bacteria if only a limited number of gingival sites are sampled. The purpose of this study was to evaluate the detection of periodontal pathogens in a large number of subgingival sites in the same children in order to determine the number of samples necessary.

METHODS

Ten children, aged 4-6 years, with complete primary dentition were enrolled in this study. Plaque samples from the mesio-buccal aspect of each erupted tooth were first collected by gently inserting a sterile paper point for 10s. Purified genomic DNA from all plaque samples was prepared for polymerase chain reaction. The primers for species-specific 16S ribosomal RNA sequence were selected as the target sequence. Standard strains of Campylobacter rectus and Tannerella forsythensis (formerly Bacteroides forsythus) were used as control strains.

RESULTS

All subjects were found positive for C. rectus and T. forsythensis with the mean of positive sites at 17.6 +/- 2.4 (range: 12-20 sites) for C. rectus and 9.3 +/- 5.0 (range: 1-19) for T. forsythensis. The mean number of positive sites was 1.7 +/- 0.8 for C. rectus and 6.5 +/- 4.9 for T. forsythensis, with a confidence ratio of 95%.

CONCLUSIONS

We concluded that two or more random sites for C. rectus and seven or more random sites for T. forsythensis from children to detect those bacteria at 95% probability.

Characteristics of Periodontal Microflora in Acute Myocardial Infarction

BACKGROUND

Periodontitis has been linked to increased risk of cardiovascular diseases. Systemic reactions associated with cardiovascular events may depend on characteristics of the subgingival microflora in periodontitis. Our objectives were to compare the numbers of cultivable bacteria, composition of subgingival microflora and clonal distribution of Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) in two groups of patients with generalized chronic periodontitis (GCP), one with an acute myocardial infarction (AMI-GCP) and the other one without AMI (non-AMI-GCP).

METHODS

In all, 150 dentate individuals were screened for suitability to this study. Subgingival bacterial samples were collected from 11 AMI-GCP and 11 non-AMI-GCP patients who had been selected using strict inclusion criteria in an attempt to exclude confounding factors and to increase comparability of periodontal conditions by matching for periodontal probing depths and attachment levels. Culture methods were used to determine the total viable counts and occurrence and proportions of six periodontal bacterial species and yeasts. Polymerase chain reaction (PCR) technique was used to detect A. actinomycetemcomitans and Porphyromonas gingivalis (P. gingivalis). Intraspecies characterization of A. actinomycetemcomitans included serotyping and genotyping.

RESULTS

The mean proportions of P. gingivalis (P = 0.05) and Tannerella forsythensis (T. forsythensis) (P = 0.01) were significantly lower, but the numbers of Micromonas micros (M. micros) and A. actinomycetemcomitans were up to nine times higher and the mean total number of cultivable bacteria per sample higher (P <0.01) in AMI-GCP than in non-AMI-GCP.

CONCLUSION

The findings that no target subgingival species were overrepresented but the total bacterial number was higher in AMI-GCP than non-AMI-GCP patients may provide support to the hypothesis that elevated numbers of bacteria in close vicinity to sterile parenteral area present a risk for systemic health.

Relationship of Actinobacillus actinomycetemcomitans serotypes to periodontal condition: prevalence and proportions in subgingival plaque

No study available has utilized the new classification scheme (the consensus report of the American Academy of Periodontology 1999) to determine the prevalence of Actinobacillus actinomycetemcomitans in different periodontal conditions. The purpose of this study was to investigate prevalence and proportions of A. actinomycetemcomitans serotypes in subgingival plaque samples from a young Taiwanese population with aggressive periodontitis, chronic periodontitis and no periodontal disease. A total of 221 subgingival plaque samples from 171 diseased subjects (70 had aggressive periodontitis, and 101 had chronic periodontitis) (mean age 25.0 +/- 8.2 yr) and 50 periodontally healthy subjects (mean age 18.4 +/- 9.5 yr) were screened for A. actinomycetemcomitans. Serotypes of A. actinomycetemcomitans were determined by an indirect immunofluorescence assay using serotype-specific polyclonal antisera to A. actinomycetemcomitans strains ATCC 29523 (serotype a), ATCC 43728 (serotype b) and ATCC 33384 (serotype c). Prevalence (% of positive samples) of A. actinomycetemcomitans was 84.3% in aggressive periodontitis, 60.4% in chronic periodontitis, and 64.0% in periodontally healthy subjects. Proportions of A. actinomycetemcomitans (mean percentage per total bacteria) in periodontally healthy subjects were significantly lower than in aggressive periodontitis subjects. The proportion of serotype b in subjects with aggressive periodontitis and subjects with chronic periodontitis were significantly greater than that in periodontally healthy subjects. The proportion of serotype c in periodontally healthy subjects was much higher than that in chronic periodontitis subjects. The results of this study suggest that prevalence and proportions of A. actinomycetemcomitans are significantly greater in patients with aggressive periodontitis than in those with chronic periodontitis. Serotype b is the predominant serotype of A. actinomycetemcomitans in patients with diseased periodontal conditions. Serotype c is a more common serotype detected in periodontally healthy subjects.

The junctional epithelium: from health to disease

The junctional epithelium is located at a strategically important interface between the gingival sulcus, populated with bacteria, and the periodontal soft and mineralized connective tissues that need protection from becoming exposed to bacteria and their products. Its unique structural and functional adaptation enables the junctional epithelium to control the constant microbiological challenge. The antimicrobial defense mechanisms of the junctional epithelium, however, do not preclude the development of gingival and periodontal lesions. The conversion of the junctional to pocket epithelium, which is regarded as a hallmark in disease initiation, has been the focus of intense research in recent years. Research has shown that the junctional epithelial cells may play a much more active role in the innate defense mechanisms than previously assumed. They synthesize a variety of molecules directly involved in the combat against bacteria and their products. In addition, they express molecules that mediate the migration of polymorphonuclear leukocytes toward the bottom of the gingival sulcus. Periodontopathogens-such as Actinobacillus actinomycetemcomitans or, in particular, Porphyromonas gingivalis-have developed sophisticated methods to perturb the structural and functional integrity of the junctional epithelium. Research has focused on the direct effects of gingipains, cysteine proteinases produced by Porphyromonas gingivalis, on junctional epithelial cells. These virulence factors may specifically degrade components of the cell-to-cell contacts. This review will focus on the unique structural organization of the junctional epithelium, on the nature and functions of the various molecules expressed by its cells, and on how gingipains may attenuate the junctional epithelium's structural and functional integrity.

Localization of Porphyromonas gingivalis-carrying fimbriae in situ in human periodontal pockets

Fimbriae, which are involved in adherence, constitute an important pathogenic factor of Porphyromonas gingivalis. In vivo, however, the distribution of P. gingivalis-carrying fimbriae is unknown. The localization of P. gingivalis-carrying fimbriae was examined in situ. From 19 patients with severe periodontitis and P. gingivalis, we obtained 20 teeth with periodontal tissue attached, with and without immunolocalized fimbriae. Eleven teeth were subjected to light microscopy, 9 to electron microscopy. In 6 of the 11 samples examined, we detected positive reactions with an anti-P. gingivalis-fimbriae serum, located in the cementum-attached plaque area in the deep pocket zones. In the so-called 'plaque-free zones', P. gingivalis-carrying fimbriae were immunocytochemically observed to reside in contact with the dental cuticle in 6 of the 9 samples examined. These findings suggest that P. gingivalis-carrying fimbriae are strongly related to adherence to the root surface at the bottoms of human periodontal pockets.

Combined effects of Nd:YAG laser irradiation with local antibiotic application into periodontal pockets

The purpose of the present study was to assess the effects of Nd:YAG laser irradiation into periodontal pockets with or without the combination of local antibiotic application on clinical parameters and microbiological prevalence. Sixteen patients, each of whom had 4 or more sites with probing depth e x 4mm were included in this study. They were monitored clinically and microbiologically at baseline, 1 and 3 months after the treatment. Subgingival plaque samples were taken from periodontally involved sites with a probing depth of e x 4mm. A total of 135 sites were randomly assigned to the following treatments; Nd:YAG laser alone (Group L: 10 pps, 200 mJ for 90 sec, n = 37), local minocycline administration following laser treatment (Group LP, n = 33), povidone-iodine irrigation following laser treatment (Group LI, n = 33), and control group (Group C: sham procedure, n = 32). The prevalence of 18 subgingival taxa were determined using the checkerboard technique. The mean value of the pocket probing depth (PPD) significantly decreased in Group L, Group LP and Group LI, and the mean clinical attachment loss (CAL) decreased in all three treatment groups. Multivariate logistic regression analysis showed that Group LP showed the most improvement in PPD or CAL at 3 months. The proportions of Porphyromonas gingivalis, Tannerella forsythia (formerly Bacteroides forsythus) and Prevotella intermedia were significantly lower in Group LP than in Group L after 3 months. These results showed that Nd:YAG laser irradiation plus local minocycline provides a much greater reduction in PPD, CAL and the amount of periodontopathogenic bacteria than laser irradiation alone in periodontitis patients.