DNA probe and enzyme analysis in periodontal diagnostics

Evaluation of leukocyte-platelet rich fibrin as an antibiotic slow-release biological device in the treatment of moderate periodontitis: a randomized controlled clinical trial

BACKGROUND

Periodontitis is a chronic inflammatory disease caused by the accumulation of biofilm. Antimicrobials have been used as adjuncts to non-surgical periodontal therapy. However, systemic antibiotics often require large dosages to achieve suitable concentrations at the disease site. Leukocyte platelet-rich fibrin (L-PRF) is a promising bio-material, with antimicrobial, anti-inflammatory, and wound-healing enhancement effects. This study aimed to evaluate the efficacy of L-PRF as a locally sustained released device for metronidazole antimicrobial.

METHODS

Twenty-four patients with eighty periodontal pockets had moderate periodontitis with attachment loss of 3-4 mm, and probing depth ≤ 5, which was equally divided into two groups: Group (I) underwent scaling and root planing with intra-pocket application of L-PRF loaded with Metronidazole, while Group (II) was treated by scaling and root planing with intra-pocket application of L-PRF alone. Microbiological measurements were taken at baseline and after one month to analyze the relative count of Porphyromonas gingivalis (P. gingivalis) using real time PCR. Clinical parameters were measured at baseline and after 1, 3, and 6 months. These parameters included probing depth (PD), clinical attachment loss (CAL), plaque index (PI), modified gingival index (MGI), and bleeding index (BI).

RESULTS

Microbiological and clinical findings revealed that both treatment methods resulted in a reduction in P. gingivalis counts, in addition to improvements in the clinical parameters: PD reduction, CAL gain, PI reduction, BI decrease and MGI reduction compared to baseline. However, L-PRF-metronidazole group showed superior results in the studied parameters over the study period. Nonetheless, there was no statistically significant improvement. (p < .001).

CONCLUSION

The intra-pocket application of both L-PRF loaded with Metronidazole and L-PRF alone contributed to the successful treatment of moderate periodontitis.

TRIAL REGISTRATION

NCT06153706 ( http://www.clinical-trials.gov/ ); 1/12/2023, retrospective registration.

Comparison of Red-Complex Bacteria Between Saliva and Subgingival Plaque of Periodontitis Patients: A Systematic Review and Meta-Analysis

The development of periodontitis is associated with an imbalanced subgingival microbial community enriched with species such as the traditionally classified red-complex bacteria (Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola). Saliva has been suggested as an alternative to subgingival plaque for the microbial analysis due to its easy and non-invasive collection. This systematic review aims to determine whether the levels of red-complex bacteria assessed using saliva reflect those in subgingival plaque from periodontitis patients. The MEDLINE, EMBASE, and Cochrane Library databases were searched up to April 30, 2021. Studies were considered eligible if microbial data of at least one of the red-complex species were reported in both saliva and subgingival plaque from periodontitis patients, based on DNA-based methods. Of the 17 included studies, 4 studies used 16S rRNA gene sequencing techniques, and the rest used PCR-based approaches. The detection frequency of each red-complex species in periodontitis patients was reported to be > 60% in most studies, irrespective of samples types. Meta-analyses revealed that both detection frequencies and relative abundances of red-complex bacteria in saliva were significantly lower than those in subgingival plaque. Moreover, the relative abundances of all 3 bacterial species in saliva showed significantly positive correlation with those in subgingival plaque. In conclusion, current evidence suggests that one-time saliva sampling cannot replace subgingival plaque for microbial analysis of the red-complex bacteria in periodontitis patients. Given the positive microbial associations between saliva and subgingival plaque, a thorough review of longitudinal clinical studies is needed to further assess the role of saliva.

Porphyromonas gingivalis outside the oral cavity

Porphyromonas gingivalis, a Gram-negative anaerobic bacillus present in periodontal disease, is considered one of the major pathogens in periodontitis. A literature search for English original studies, case series and review articles published up to December 2019 was performed using the MEDLINE, PubMed and GoogleScholar databases, with the search terms "Porphyromonas gingivalis" AND the potentially associated condition or systemic disease Abstracts and full text articles were used to make a review of published research literature on P. gingivalis outside the oral cavity. The main points of interest of this narrative review were: (i) a potential direct action of the bacterium and not the systemic effects of the inflammatory acute-phase response induced by the periodontitis, (ii) the presence of the bacterium (viable or not) in the organ, or (iii) the presence of its virulence factors. Virulence factors (gingipains, capsule, fimbriae, hemagglutinins, lipopolysaccharide, hemolysin, iron uptake transporters, toxic outer membrane blebs/vesicles, and DNA) associated with P. gingivalis can deregulate certain functions in humans, particularly host immune systems, and cause various local and systemic pathologies. The most recent studies linking P. gingivalis to systemic diseases were discussed, remembering particularly the molecular mechanisms involved in different infections, including cerebral, cardiovascular, pulmonary, bone, digestive and peri-natal infections. Recent involvement of P. gingivalis in neurological diseases has been demonstrated. P. gingivalis modulates cellular homeostasis and increases markers of inflammation. It is also a factor in the oxidative stress involved in beta-amyloid production.

Coated floss for drug delivery into the gum pocket

The purpose of this study was to develop a drug-coated floss to allow delivery of therapeutics into diseased gum pocket. Periodontal (gum) disease affects nearly 45% of adults over 30 years of age. Bacterial persistence makes treatment challenging. Drug-coated floss is expected to provide a self-administrable and targeted method for drug delivery into the diseased gum pockets. We investigated various types of floss and sutures as potential candidates to coat drug. An un-waxed nylon braided floss was selected and dip-coated with model hydrophilic and hydrophobic drugs either in free form or after encapsulation in poly(lactic-co-glycolic acid) particles. By tuning the drug concentration or the number of times a floss is dipped into the coating solution we were able to coat from as little as 0.4 μg to as high as 1.6 mg of drug. Coated floss was passed within the gum pocket of excised porcine mandibles to demonstrate delivery efficiency up to 91%. Utilizing the porcine jaw in an ex-vivo condition we illustrated the ability of the delivered drug to diffuse into the tissue. Overall, the data illustrates the potential of coated floss as an innovative modality for drug delivery to the gum pocket.

Periodontitis and bone metabolism in patients with advanced heart failure and after heart transplantation

AIMS

Heart failure (HF) is a multi-organ, pro-inflammatory syndrome that impairs bone metabolism. Pro-inflammatory cytokines and bone catabolism enhance periodontal disease, a local inflammatory, bacteria-induced disease that causes bone loss and periodontal soft tissue destruction.

METHODS AND RESULTS

Medical and dental examinations were performed on patients with HF (n = 39), following heart transplantation (post-HTx, n = 38) and controls (n = 32). Blood, saliva, and gingival crevicular fluid were analysed for bone metabolism and inflammation markers. HF average New York Heart Association classification was III. Average time since HTx was 1414 days. Pro-inflammatory tumour necrosis factor-alpha was higher in HF and HTx as compared with controls (P < 0.05). Both HF and HTx participants had higher levels of bone resorption marker C-terminal telopeptide and parathyroid hormone with subjects in the HF group having the highest serum levels of all groups (P ≤ 0.05). In contrast, 25-hydroxyvitamin D was lowest in HF. HF patients had greater clinical attachment loss, cumulative pockets depth (greater than 3 mm) and probing depth (P < 0.05) as compared with controls. Cumulative pockets depth correlated significantly with measures of the inflammatory burden, β-glucuronidase in saliva (r = 0.4863, P < 0.01), interleukin-1b in saliva (r = 0.5149, P < 0.01), and gingival crevicular fluid (r = 0.6056, P < 0.001) in HF. However, adjustment of periodontal results for measures of oral hygiene (plaque, bleeding on probing), systemic 25-hydroxyvitamin D, and race attenuated significant differences between groups.

CONCLUSIONS

Patients with HF exhibit more severe periodontal disease associated with increased bone turnover markers when compared with control patients. However, local and systemic factors may account for this association and should be evaluated in future studies.

Deoxyribonucleic Acid Probes Analyses for the Detection of Periodontal Pathogens

BACKGROUND

In clinical microbiology several techniques have been used to identify bacteria. Recently, Deoxyribonucleic acid (DNA)-based techniques have been introduced to detect human microbial pathogens in periodontal diseases. Deoxyribonucleic acid probes can detect bacteria at a very low level if we compared with the culture methods. These probes have shown rapid and cost-effective microbial diagnosis, good sensitivity and specificity for some periodontal pathogens in cases of severe periodontitis.

MATERIALS AND METHODS

Eighty-five patients were recruited for the study. Twenty-one subjects ranging between 22 and 48 years of age fulfilled the inclusion and exclusion criteria. Seventy-eight samples became available for DNA probe analysis from the deepest pockets in each quadrant.

RESULTS

All 21 patients showed positive results for Prevotella intermedia; also, Prevotella gingivalis was identified in 19 subjects, Aggregatibacter actinomycetemcomitans in 6 subjects. P. intermedia was diagnosed positive in 82% of the subgingival samples taken, 79% for P. gingivalis, and 23% for A. actinomycetemcomitans.

CONCLUSION

This study shows a high frequency of putative periodontal pathogens by using DNA probe technology, which is semi-quantitative in this study. Deoxyribonucleic acid probes can detect bacteria at very low level about 10(3) which is below the detection level of culture methods. The detection threshold of cultural methods.

CLINICAL SIGNIFICANCE

The three types of bacteria can be detected rapidly with high sensitivity by using the DNA probe by general practitioners, and thus can help in the diagnosis process and the treatment.

Evaluation of a novel immunochromatographic device for rapid and accurate clinical detection of Porphyromonas gingivalis in subgingival plaque

An important goal for the improved diagnosis and management of infectious and inflammatory diseases, such as periodontitis, is the development of rapid and accurate technologies for the decentralized detection of bacterial pathogens. The aim of this prospective multicenter study was to evaluate the clinical use of a novel immunochromatographic device with monoclonal antibodies for the rapid point-of-care detection and semi-quantification of Porphyromonas gingivalis in subgingival plaque. Sixty-three patients with chronic periodontitis and 28 periodontally healthy volunteers were subjected to clinical and microbiological examinations. Subgingival plaque samples were analyzed for the presence of P. gingivalis using a novel immunochromatography based device DK13-PG-001, designed to detect the 40k-outer membrane protein of P. gingivalis, and compared with a PCR-Invader method. In the periodontitis group, a significant strong positive correlation in detection results was found between the test device score and the PCR-Invader method (Spearman rank correlation, r=0.737, p<0.0001). The sensitivity, specificity, and positive and negative predictive values of the test device were 96.2%, 91.8%, 90.4% and 96.7%, respectively. The detection threshold of the test device was determined to be approximately 10(4) (per two paper points). There were significant differences in the bacterial counts by the PCR-Invader method among groups with different ranges of device scores. With a cut-off value of ≥0.25 in device score, none of periodontally healthy volunteers were tested positive for the subgingival presence of P. gingivalis, whereas 76% (n=48) of periodontitis subjects were tested positive. There was a significant positive correlation between device scores for P. gingivalis and periodontal parameters including probing pocket depth and clinical attachment level (r=0.317 and 0.281, respectively, p<0.01). The results suggested that the DK13-PG-001 device kit can be effectively used for rapid, chair-side detection and semi-quantification of P. gingivalis in subgingival plaque.

TRIAL REGISTRATION

UMIN Clinical Trials Registry (UMIN-CTR) UMIN000011943.

Comparing culture, real-time PCR and fluorescence resonance energy transfer technology for detection of Porphyromonas gingivalis in patients with or without peri-implant infections

BACKGROUND AND OBJECTIVE

The aim of the study was to compare the detection of Porphyromonas gingivalis using a fluorescence resonance energy transfer (FRET) technology with commonly used diagnostic methods in salivary and subgingival plaque samples from subjects with dental implants. P. gingivalis was considered as a marker for a pathogenic microbiota.

MATERIAL AND METHODS

Ninety-seven adult subjects were recruited, including periodontally healthy controls with no dental implants, implant controls with no peri-implant disease and patients with peri-implant disease. Saliva and subgingival/submucosal plaque samples were collected from all subjects and were analyzed using culture, real-time PCR and FRET technology employing P. gingivalis-specific substrates.

RESULTS

It was found that the P. gingivalis-specific substrates were highly suitable for detecting the presence of P. gingivalis in saliva and in subgingival plaque samples, showing comparable specificity to culture and real-time PCR.

CONCLUSION

We applied the FRET technology to detect P. gingivalis in implant patients with or without an implant condition and in controls without implants. The technique seems suitable for detection of P. gingivalis in both plaque and saliva samples. However, with all three techniques, P. gingivalis was not very specific for peri-implantitis cases. Future work includes fine-tuning the FRET technology and also includes the development of a chair-side application.

Comparison of subgingival bacterial sampling with oral lavage for detection and quantification of periodontal pathogens by real-time polymerase chain reaction

BACKGROUND

Saliva has been studied for the presence of subgingival pathogens in periodontitis patients. With the anaerobic culture technique, the discrepancy between salivary recovery and subgingival presence has been significant, which makes this approach not suitable for practical use in the microbial diagnosis of periodontitis patients. The real-time polymerase chain reaction (PCR) technique represents a very sensitive technique to detect and quantify bacterial pathogens. The aim of the study was to compare the presence and numbers of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythensis, Prevotella intermedia, and Micromonas micros in subgingival plaque and mouthwash samples by the anaerobic culture and real-time PCR techniques.

METHODS

Pooled subgingival plaque samples and 10-ml mouthwash samples were collected from 21 adult patients with periodontitis and analyzed by quantitative anaerobic culture and real-time PCR for A. actinomycetemcomitans, P. gingivalis, T. forsythensis, P. intermedia, and M. micros.

RESULTS

The detection frequency of A. actinomycetemcomitans, P. gingivalis, and T. forsythensis in subgingival plaque was identical by culture and real-time PCR and was higher for P. intermedia and M. micros by real-time PCR. The highest detection frequencies for the target bacteria were found in mouthwash samples by real-time PCR. The additional value of the real-time PCR to detect target bacteria was 38% for P. gingivalis, 73% for T. forsythensis, 77% for P. intermedia, and 71% for M. micros. The sensitivity to detect target species in mouthwash by real-time PCR was 100% for all test species except for P. intermedia (93.8%).

CONCLUSIONS

Rapid detection and quantification of periodontal pathogens in mouthwash samples are possible by real-time PCR. The procedure is significantly less time-consuming than subgingival sampling with paper points. This approach to detect major periodontal pathogens in mouthwash samples may simplify microbial diagnosis in periodontitis patients and may be used to monitor periodontal treatment.

The additional value of real-time PCR in the quantitative detection of periodontal pathogens

BACKGROUND AND AIM

For the analysis of subgingival plaque, anaerobic bacterial culture has been the gold standard for many years. Currently, molecular microbial techniques have become available to identify and quantify target organisms with high specificity and sensitivity. The technique of real-time polymerase chain reaction(RT-PCR) provides a new tool to detect oral pathogens both in oral and non-oral human infections. The aim of this study was to compare the RT-PCR and anaerobic culture for detection and quantification of six periodontal pathogens in periodontal health and disease.

MATERIAL AND METHODS

Subgingival plaque samples from 259 adult patients with periodontitis and 111 healthy controls were analysed with quantitative anaerobic culture and quantitative RT-PCR for Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, Micromonas micros and Fusobacterium spp.

RESULTS

All species were more frequently isolated from patients than controls with both culture and RT-PCR. P. gingivalis, T. forsythia and M. micros appeared significant markers for disease with both techniques. P. intermedia was significantly associated with periodontitis by RT-PCR only (OR 9.7), whereas A. actinomycetemcomitans showed a significant relationship by culture only. The critical differences between culture and RT-PCR were culture-negative/PCR-positive samples which amounted to 7% for A. actinomycetemcomitans, 3% for P. gingivalis, 7% for T. forsythia, 20% for P. intermedia, 6% for M. micros, and 0.8% for Fusobacterium spp. in periodontitis patients and 12%, 3%, 2%, 35%, 14% and 0%, respectively, in the periodontally healthy group. Furthermore, periodontitis individuals had significantly higher amount of all of the test species in the subgingival plaque samples compared with healthy subjects.

CONCLUSION

RT-PCR provides a new rapid diagnostic tool and opens the opportunity to detect small numbers of oral pathogens in clinical specimens, which are under the detection limit by culture technique.

Methods of detection of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythensis in periodontal microbiology, with special emphasis on advanced molecular techniques: a review

BACKGROUND

Certain specific bacterial species from the subgingival biofilm have demonstrated aetiological relevance in the initiation and progression of periodontitis. Among all the bacteria studied, three have shown the highest association with destructive periodontal diseases: Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg) and Tannerella forsythensis (Tf). Therefore, the relevance of having accurate microbiological diagnostic techniques for their identification and quantification is clearly justified.

AIM

To evaluate critically all scientific information on the currently available microbial diagnostic techniques aimed for the identification and quantification of Aa, Pg and Tf.

SUMMARY

Bacterial culturing has been the reference diagnostic technique for many years and, in fact, most of our current knowledge on periodontal microbiology derives from cultural data. However, the advent of new microbial diagnostics, mostly based on immune and molecular technologies, has not only highlighted some of the shortcomings of cultural techniques but has also allowed their introduction as easy and available adjunct diagnostic tools to be used in clinical research and practice. These technologies, mostly polymerase chain reaction (PCR), represent a field of continuous development; however, we still lack the ideal diagnostic to study the subgingival microflora. Qualitative PCR is still hampered by the limited information provided. Quantitative PCR is still in development; however, the promising early results reported are still hampered by the high cost and the equipment necessary for the processing.

CONCLUSION

Quantitative PCR technology may have a major role in the near future as an adjunctive diagnostic tool in both epidemiological and clinical studies in periodontology. However, culture techniques still hold some inherent capabilities, which makes this diagnostic tool the current reference standard in periodontal microbiology.

Comparison of real-time PCR and culture for detection of Porphyromonas gingivalis in subgingival plaque samples

Porphyromonas gingivalis is a major pathogen in destructive periodontal disease in humans. Detection and quantification of this microorganism are relevant for diagnosis and treatment planning. The prevalence and quantity of P. gingivalis in subgingival plaque samples of periodontitis patients were determined by anaerobic culture and real-time PCR amplification of the 16S small-subunit rRNA gene. The PCR was performed with primers and a fluorescently labeled probe specific for the P. gingivalis 16S rRNA gene. By the real-time PCR assay, as few as 1 CFU of P. gingivalis could be detected. Subgingival plaque samples from 259 adult patients with severe periodontitis were analyzed. P. gingivalis was detected in 111 (43%) of the 259 subgingival plaque samples by culture and in 138 (53%) samples by PCR. The sensitivity, specificity, and positive and negative predictive values of the real-time PCR were 100, 94, 94, and 100%, respectively. We conclude that real-time PCR confirms the results of quantitative culture of P. gingivalis and offers significant advantages with respect to the rapidity and sensitivity of detection of P. gingivalis in subgingival plaque samples.

Detection of Tannerella forsythensis (Bacteroides forsythus) and porphyromonas gingivalis by polymerase chain reaction in subjects with different periodontal status

BACKGROUND

The aim of this study was to determine the prevalence of Tannerella forsythensis (formerly Bacteroides forsythus) and Porphyromonas gingivalis in subgingival plaque samples by using polymerase chain reaction (PCR), and to assess the relationship of these bacteria with different categories of periodontal disease and health.

METHODS

Subjects were distributed into 3 groups according to their periodontal diagnosis: group 1, periodontally healthy (N = 10); group 2, periodontitis with probing depth < or = 5 mm (N = 10); group 3, periodontitis with probing depth > 5 mm (N = 10). The subjects in groups 2 and 3 had healthy and diseased periodontal sites. Subgingival plaque samples were obtained using paper points inserted into periodontal pockets (diseased sites) and into healthy gingival sulci (healthy sites) of the same subject.

RESULTS

The distribution of bacteria differed in healthy and diseased sites. T. forsythensis (B. forsythus) was not detected in any sample from healthy sites in any group but was detected in 70% and 100% of diseased sites in groups 2 and 3, respectively. P. gingivalis was detected in only one sample from a healthy site (group 2), and in the diseased sites, its prevalence was 40% (group 2) and 90% (group 3). In addition, T. forsythensis (B. forsythus) and P. gingivalis were both detected in 30% and 90% of the diseased sites in groups 2 and 3, respectively.

CONCLUSION

These results indicate a possible association between periodontal disease and the presence of T. forsythensis (B. forsythus) and/or P. gingivalis.

Comparison of 16S rDNA-based PCR and checkerboard DNA-DNA hybridisation for detection of selected endodontic pathogens

Molecular methods have been used recently to investigate the bacteria encountered in human endodontic infections. The aim of the present study was to compare the ability of a 16S rDNA-based PCR assay and checkerboard DNA-DNA hybridisation in detecting Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Peptostreptococcus micros, Porphyromonas endodontalis, Por. gingivalis and Treponema denticola directly from clinical samples. Specimens were obtained from 50 cases of endodontic infections and the presence of the target species was investigated by whole genomic DNA probes and checkerboard DNA-DNA hybridisation or taxon-specific oligonucleotides with PCR assay. Prevalence of the target species was based on data obtained by each method. The sensitivity and specificity of each molecular method was compared with the data generated by the other method as the reference--a value of 1.0 representing total agreement with the chosen standard. The methods were also compared with regard to the prevalence values for each target species. Regardless of the detection method used, T. denticola, Por. gingivalis, Por. endodontalis and B. forsythus were the most prevalent species. If the checkerboard data for these four species were used as the reference, PCR detection sensitivities ranged from 0.53 to 1.0, and specificities from 0.5 to 0.88, depending on the target bacterial species. When PCR data for the same species were used as the reference, the detection sensitivities for the checkerboard method ranged from 0.17 to 0.73, and specificities from 0.75 to 1.0. Accuracy values ranged from 0.6 to 0.74. On the whole, matching results between the two molecular methods ranged from 60% to 97.5%, depending on the target species. The major discrepancies between the methods comprised a number of PCR-positive but checkerboard-negative results. Significantly higher prevalence figures for Por. endodontalis and T. denticola were observed after PCR assessment. There was no further significant difference between the methods with regard to detection of the other target species.

Clinical and microbiological studies of periodontal disease in Sjögren syndrome patients

BACKGROUND

Little is known about the periodontal status of patients with Sjögren's Syndrome (SS), a chronic inflammatory autoimmune disease characterized by xerophthalmia and xerostomia. The aim of the present study was to evaluate whether the periodontal status of SS patients, in terms of clinical and microbiological parameters, differs from systemically healthy age- and gender-matched controls.

METHODS

8 primary SS and 10 secondary SS patients were examined in comparison with 11 control subjects. All patients were diagnosed by the European Community Criteria. Control subjects were systemically healthy and not undergoing periodontal treatment. The comparison of clinical status was made in terms of mean periodontal parameters (plaque index, gingival index, gingival recession, probing pocket depth, probing attachment level and bleeding on probing) as well as the frequency distribution of probing pocket depth and probing attachment level measurements. Microbiological assays of the subgingival dental plaque samples were carried out by both a chairside enzyme test (Periocheck) for the detection of peptidase activity (PA) and a polymerase chain reaction (PCR) analysis for 9 selected periodontal micro-organisms (Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, Prevotella intermedia, Treponema denticola, Porphyromonas gingivalis, Eikenella corrodens, Campylobacter rectus, Bacteroides forsythus, Streptococcus oralis).

RESULTS

The occurrence, severity and extent of periodontal lesions were not significantly different between the 3 patient groups for all periodontal parameters examined. No significant differences in the sub-gingival plaque samples from control, primary or secondary SS patients for the PA test, frequency or type of periodontal micro-organisms observed.

CONCLUSION

No significant differences could be detected in either clinical or microbiological parameters of primary or secondary SS patients compared with that of control subjects. The results of the present study thus support the notion that the periodontal status of patients with SS do not differ from systemically healthy age- and gender-matched controls.

A sensitive method for detecting Porphyromonas gingivalis by polymerase chain reaction and its possible clinical application

BACKGROUND

It is useful for the clinical diagnosis of periodontitis to monitor the colonization of periodontopathic bacteria in periodontal pockets. In this study, we attempted to establish and possibly identify the clinical application of a sensitive method to detect Porphyromonas gingivalis (P.g.), one of the putative periodontopathic bacteria related to chronic periodontitis.

METHODS

Genomic DNA extracted from cultured P.g. 381 and clinically isolated subgingival plaque samples were used as a template of polymerase chain reaction (PCR). We designed primers to amplify the genomic DNA coding 40 kDa outer membrane protein (OMP), one of the unique proteins to all strains of P.g. The efficiency and specificity of amplification were evaluated by agarose gel electrophoresis and subsequent Southern hybridization with a digoxygenin-labeled oligonucleotide probe.

RESULTS

Fewer than 100 P.g. bacterial cells in the specimen were reproducibly detected by PCR-hybridization assay. This PCR-hybridization assay was at least 100 times more sensitive than the conventional indirect immunofluorescence assay (IIF). Furthermore, the imaging analysis showed that there is a linear correlation between the strength of the signal and the cell number of P.g. from which the template DNA was extracted semiquantitatively. It is noteworthy that the PCR assay could also be applied to detect P.g. from clinical plaque samples and that it was approximately 100 times more sensitive than a conventional IIF assay.

CONCLUSION

The PCR assay established in this study can be a powerful tool to detect P.g. in periodontal pockets and monitor the colonization and/or recolonization of P.g. at the very early phase.

A rapid DNA probe method for detection of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans

BACKGROUND

The objective of the present study was to develop a rapid DNA probe method for the microbiological detection of periodontitis that can be used in dental clinics. By using the DNA probe, we also investigated the correlation between the occurrence of putative periodontopathic bacteria and clinical parameters.

METHODS

This rapid DNA probe method minimizes the use of a water bath for ordinary hybridization and washing in order to shorten the total reaction time. The detection process could be completed within 2 hours. In order to evaluate the clinical application of the DNA probe, subgingival plaque samples were taken from patients with periodontitis before initial therapy. After the therapy, the patients were microbiologically and clinically evaluated.

RESULTS

When the DNA probe method was compared with the culture method, the agreement was 88% for Porphyromonas gingivalis and 67% for Actinobacillus actinomycetemcomitans. A statistically significant association was found between the detection of P. gingivalis and probing depth, bleeding on probing (chi2 test: P <0.001, P <0.05). A significant association was also shown between the detection of A. actinomycetemcomitans and probing depth in patients aged 35 or older (chi2 test: P <0.001). The detection rate of A. actinomycetemcomitans was highest in teenagers. At shallow periodontal pocket sites (PD < or =3 mm) in teenagers, no P. gingivalis was found, while 22% of the sites harbored A. actinomycetemcomitans. After the therapy, the frequency of detection of P. gingivalis decreased significantly only in the clinically improved sites (chi2 test: P <0.001).

CONCLUSIONS

The rapid DNA probe method appears promising as an efficient tool for rapid clinical detection of periodontopathic bacteria.

Periodontopathic bacteria in children with Down syndrome

BACKGROUND

It is widely known that individuals with Down syndrome (DS) often develop severe early-onset periodontal diseases. In this study, we examined the prevalence of periodontopathic bacteria in DS children to determine if specific pathogens are acquired in their childhood.

METHODS

The subjects were 60 DS children (2 to 13 years old, 5 in each age bracket) and 60 age-matched controls. Ten pathogens, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Bacteroides forsythus, Treponema denticola, Prevotella intermedia, P nigrescens, Capnocytophaga ochracea, C. sputigena, Campyrobacter rectus, and Eikenella corrodens were surveyed in subgingival plaque samples using a polymerase chain reaction. Periodontal status was evaluated by probing depth, bleeding on probing, and gingival index.

RESULTS

No significant difference in periodontal status was observed between the DS and control groups, however, all of the pathogens were detected with greater frequency in the DS children. B. forsythus, T. denticola, P. nigrescens, and C. rectus were significantly prevalent throughout all age brackets of the DS children (P <0.01 or 0.05). The occurrence of P. gingivalis was also significant in the DS subjects over 5 years old. A cluster analysis of the microbial profiles of the DS subjects showed that gingivitis severity was associated with increased varieties of the harboring pathogens and the distribution of P. gingivalis.

CONCLUSIONS

These results suggest that various periodontopathogens can colonize in the very early childhood of DS patients and maturation of subgingival components, including P. gingivalis, plays an important role in the initiation of gingival inflammation.

Distribution of Porphyromonas gingivalis strains with fimA genotypes in periodontitis patients

Fimbriae (FimA) of Porphyromonas gingivalis are filamentous components on the cell surface and are thought to play an important role in the colonization and invasion of periodontal tissues. We previously demonstrated that fimA can be classified into four variants (types I to IV) on the basis of the nucleotide sequences of the fimA gene. In the present study, we attempted to detect the four different fimA genes in saliva and plaque samples isolated from patients with periodontitis using the PCR method. Four sets of fimA type-specific primers were designed for the PCR assay. These primers selectively amplified 392-bp (type I), 257-bp (type II), 247-bp (type III), and 251-bp (type IV) DNA fragments of the fimA gene. Positive PCR results were observed with reference strains of P. gingivalis in a type-specific manner. All other laboratory strains of oral and nonoral bacteria gave negative results. The sensitivity of the PCR assay for fimA type-specific detection was between 5 and 50 cells of P. gingivalis. Clinical samples were obtained from saliva and subgingival plaque from deep pockets (>/=4 mm) of 93 patients with periodontitis. Bacterial genomic DNA was isolated from the samples, and the targeted fragments were amplified by PCR. The presence of P. gingivalis was demonstrated in 73 patients (78.5%), and a single fimA gene was detected in most patients. The distribution of the four fimA types among the P. gingivalis-positive patients was as follows: type I, 5.4%; type II, 58.9%; type III, 6. 8%; type IV, 12.3%; types I and II, 6.8%; types II and IV, 2.7%; and untypeable, 6.8%. P. gingivalis with type II fimA was detected more frequently in the deeper pockets, and a significant difference of the occurrence was observed between shallow (4 mm) and deep (>/=8 mm) pockets. These results suggest that P. gingivalis strains that possess type II fimA are significantly more predominant in periodontitis patients, and we speculate that these organisms are involved in the destructive progression of periodontal diseases.

The importance of fimbriae in the virulence and ecology of some oral bacteria

Cumulative evidence indicates that bacterial adherence to mucosal and tooth surfaces as well as bacterial coaggregation are essential steps for colonization of various oral bacterial species. Bacterial fimbriae have been shown to play an important role in the interaction between bacteria and host cells or among bacterial cells. The properties of fimbriae from selected species of oral bacteria are discussed in terms of virulence traits and ecological significance. Among others, Porphyromonas gingivalis fimbriae have been most extensively studied. The fimbrial structure is composed of 41-kDa fimbrillin proteins. DNA sequencing of the fimbrillin gene (fimA) from nine strains of P. gingivalis suggests intraspecies variation in the structure of fimA, while retaining common immunochemical specificities. P. gingivalis fimbriae exhibit a wide variety of biological activities including immunogenicity, binding to various host proteins, stimulation of cytokine production and promotion of bone resorption, Actinobacillus actinomycetemcomitans also possesses fimbriae; however, little is known concerning their chemical, genetical, and biological properties. Fimbriae of Prevotella intermedia are shown to induce hemagglutination reaction, while those of Prevotella loescheii are found to cause coaggregation with other bacteria, i.e., Actinomyces viscosus and sanguis streptococci. Fimbriae from gram-positive oral bacteria such as oral Actinomyces and sanguis streptococci are described. These fimbriae may participate in coaggregation, binding to saliva-coated hydroxyapatite or glycoprotein of the surface layer of oral epithelial cells. Taken together, fimbriae are key components in cell-to-surface and cell-to-cell adherence of oral bacteria and pathogenesis of some oral and systemic diseases.

Identification of bacterial markers by culture technique in evaluation of periodontal therapy

The aim of the present study was to evaluate whether the presence of A. actinomycetemcomitans, P. gingivalis and P. intermedia, as revealed by culture technique, could discriminate between three distinct adult patient groups, those: with recurrent periodontal disease, with cured periodontal disease or who were periodontally healthy. Forty one patients previously treated for advanced periodontitis were divided into recurrent or cured groups, with a third periodontally healthy reference group. All subjects were sampled for the three bacterial strains under scrutiny. Although all three micro-organisms were found significantly more often in diseased sites, it was concluded that a sample positive for all three may indicate a false record of disease activity. However, a sample negative for the three bacteria strongly indicates an absence of disease activity.

Rapid detection of Actinobacillus actinomycetemcomitans, Prevotella intermedia and Porphyromona gingivalis by multiplex PCR

The identification of specific periodontal pathogens by conventional methods, mainly anaerobic cultivation, is difficult, time consuming and even sometimes unreliable. Therefore, a multiplex PCR method for simultaneous detection of Actinobacillus actinomycetemcomitans (A.a.), Porphyromona gingivalis (P.g.) and Prevotella intermedia (P.i.) was developed for rapid and easy identification of these specific bacterial pathogens in subgingival plaque samples. In this paper, there is a detailed description of the oligonucleotide primer selection, DNA extraction and PCR conditions and the sequencing of the amplified products. The locus chosen to be amplified is a highly variable region in the 16S ribosomal DNA. For the development of this technique ATCC cultures and pure cultures from subgingival plaque samples taken from periodontitis patients were used. As an internal positive control a recombinant plasmid was developed. This simple DNA extraction procedure and the DNA amplification and visualization of the amplified product permits the detection of the bacteria in a working day. Thus, this multiplex PCR method is a rapid and effective detection method for specific periodontal pathogens.

Assessment of pretreatment orthodontic patients using the BANA test. N-benzoyl-DL-arginine-naphthylamide

Ninety-two subjects were tested before orthodontic mechanotherapy for the presence of three putative periodontopathogens-Porphyromonas gingivalis, Treponema denticola, and Bacteroides forsythus-with the BANA test (PerioScan Oral-B). The sample ranged from 9 to 16 years, with a mean age of 13.1 years, and consisted of 51% girls and 49% boys; 48% African American, 46% white, 4% Asian, and 2% Hispanic. Unlike other BANA studies that examined children and adolescents with a 15-minute incubation time, this research used a 5-minute incubation time to increase the specificity and to reduce the false positives obtained from the PerioScan cards. No statistically significant difference was found between the age, gender, or race of the patients and the levels of the three putative periodontopathogens. A Friedman two-way analysis of variance assessed the BANA levels for three groups of teeth: molars, incisors, and premolars. The central incisors and first molars had a significantly higher percentage of positive BANA readings than the first premolars at p < or = 0.05. The clinical importance of this finding has yet to be determined, however, because the central incisor and first molar are the first permanent teeth to erupt, a possible association between dental emergence time and the rate of infection with various organisms may be postulated. In a pilot study, 10 patients from a statistically comparable pretreatment group were assessed longitudinally at two separate collection times separated by 4 months. The Wilcoxon signed rank test indicated no significant changes in these patients over the 4-month period.

Principles of evaluation of the diagnostic value of subgingival bacteria

This paper describes steps in the process of evaluating subgingival bacteria assays for the diagnosis of periodontal disease. The first step examines the infectious etiology of periodontal disease in pointing to specific oral bacteria as periodontal pathogens. Second is characterization of the laboratory test to detect and quantitate these pathogens as to sensitivity, specificity, and positive and negative predictive value. Third is the role of the laboratory test in the diagnosis of the different forms of periodontal disease which is related to the current clinical rather than microbiological definition of these diseases. The fourth and most important step is an analysis of the significance of subgingival bacterial tests in clinical decision-making.

Rapid diagnosis of periodontal infections: findings in AIDS patients

A small number of bacterial pathogens in the human oral cavity cause the different forms of periodontal disease. Of the approximately two hundred different oral bacterial species, about a dozen have been associated with these diseases including localized juvenile periodontitis, rapidly progressing periodontitis, and adult periodontitis. These species include Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Campylobacter rectus, Porphyromonas gingivalis, and Prevotella intermedia. Several rapid methods have been developed to detect these species in clinical samples. These include immunologic methods such as immunofluorescence, nucleic acid assays such as DNA-DNA hybridization in dot blots and enzyme assays. Immunofluorescence microscopy has been used to determine the prevalence and relative proportions of these pathogens in dental plaque samples from 194 subjects including HIV-infected and uninfected male homosexuals and intravenous drug users.

Occurrence of Porphyromonas gingivalis, Bacteroides forsythus, and Treponema denticola in periodontally healthy and diseased subjects as determined by an ELISA technique

The aim of this study was to assess by means of an ELISA technique, the occurrence of 3 putative periodontopathogens, Porphyromonas gingivalis, Bacteroides forsythus, and Treponema denticola, in 3 clinically-defined adult periodontal conditions. Thirty systemically-healthy subjects were selected and grouped into 3 categories according to their periodontal health: 1) 10 periodontitis subjects (PS), having moderate adult chronic periodontitis; 2) 10 untreated gingivitis subjects (UGS), exhibiting no signs of periodontal destruction but presenting with clinical signs of mild gingivitis; and, 3) 10 treated gingivitis subjects (TGS), having the same clinical status as UGS, but who received a thorough prophylaxis treatment within the past 7 to 14 days prior to the baseline examination. A total of 60 samples were collected subgingivally from the six Ramfjord teeth per subject in each group and ELISA analysis was carried out to give a semiquantitative estimate of P. gingivalis. B. forsythus, and T. denticola. The immunologic detection method suggested the presence of antigens of P. gingivalis, B. forsythus, and T. denticola in subjects from each of the 3 groups. When a global analysis for the 3 disease groups was performed at one time, statistically significant differences were found among the ELISA scores of the 3 bacterial species. For example, comparisons of the ELISA scores showed that the concentrations of P. gingivalis differed significantly when comparing TGS to UGS and PS, but not when examining UGS/PS. The ELISA scores for B. forsythus were significantly different between TGS and PS. Mean concentrations of T. denticola were significantly different when comparing PS to TGS or UGS, whereas no difference was found between the latter categories. Within the limited scope of this study, the concentration of antigens detectable from putative periodontopathogens like P. gingivalis, B. forsythus, and T. denticola differed among the 3 diseased groups, with periodontitis subjects often showing the greatest level of antigens. Thus, it is reasonable to expect that, when using sensitive immunological detection methods, antigens of suspected periodontal pathogens can be found irrespective of the individual's clinical status. However, while detectable in the periodontal sites, the concentrations of these microorganisms are most likely to be above the threshold necessary to induce clinically-significant disease. Studies with larger sample size and standardized antigens are necessary to determine if the groups we found not to differ, were, in fact, different.

Specific antibody reactivity against a 110-kilodalton Actinobacillus actinomycetemcomitans protein in subjects with periodontitis

The purpose of the present study was to determine the serum immunoglobulin A (IgA), IgM, and IgG reactivities against proteins of Actinobacillus actinomycetemcomitans in patients with periodontitis. Serum samples from 20 patients with early-onset periodontitis, 20 patients with adult periodontitis, and 20 age- and sex-matched healthy controls were assessed by immunoblot analysis. IgG antibody reactivity against a sarcosyl-insoluble 110-kDa protein of A. actinomycetemcomitans was detected in 65 and 45% of patients with early-onset periodontitis and adult peritonitis, respectively, and IgA antibodies against this protein were found in 70 and 55% of these patients, respectively. However, control subjects showed no IgG reactivity, and IgA antibodies against the sarcosyl-insoluble 110-kDa protein were detected in only 5% of the patients (P < 0.05). There was no IgM antibody reactivity against this protein in any of the diseased or healthy subjects. The sensitivity and specificity of serum IgA antibody reactivity against the 110-kDa protein in detecting subgingival A. actinomycetemcomitans infection, as determined by PCR, were 77 and 66%, respectively. The results of the study indicated that the sarcosyl-insoluble 110-kDa protein is a potential candidate for use in the serodiagnosis of periodontal disease.

Treatment of periodontal disease based on microbiological diagnosis. A 5-year follow-up on individual patterns

Sixteen patients with advanced periodontitis (more than 3 sites with a probing depth > or = 6 mm) were treated with the aim of eliminating Actinobacillus actinomyce-temcomitans and Porphyromonas gingivalis and reducing Prevotella intermedia below 5% of the total viable count. The patients were followed clinically and microbiologically for over 5 years and showed a highly individual pattern with respect to presence of indicator bacteria, type of treatment needed to accomplish treatment goals, clinical response, and bacterial and disease recurrencies. The results of this study suggest that presence of the indicator bacteria in microbial samples taken after treatment may identify patients at risk for recurrent periodontitis.

Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans and Treponema denticola detection in oral plaque samples using the polymerase chain reaction

Detection of putative pathogens is critical for delineating the etiology and progression of periodontitis. In the present study, we have used a polymerase chain reaction (PCR) assay utilizing primers specific for the lkt A gene of Actinobacillus actinomycetemcomitans, the fimbrial gene of Porphyromonas gingivalis, and tdp A gene of Treponema denticola in order to determine the presence of these pathogens in subgingival plaque samples from periodontitis sites. These gene specific primers were also used to assess the detection of different strains of bacteria in the PCR assays. Primers for P. gingivalis detected P. gingivalis strain 33277, but no product was detected when primers were used with extracts from 4 species of Capnocytophaga, 3 species of Prevotella, 2 species of Porphyromonas other than P. gingivalis, Bacteroides levii, Escherichia coli, 3 strains of A. actinomycetemcomitans and 3 strains of T. denticola. PCR analysis using primers for the lkt A gene of A. actinomycetemcomitans also did not result in a product with any of these bacteria with the exception of a positive result with 3 different strains of A. actinomycetemcomitans. Primers selected from the tdp A gene of T. denticola did not identify any of the bacteria strains tested except T. denticola serovars a, b, and c. Thus, these primers were shown to amplify gene segments that are specific to either P. gingivalis (33277), A. actinomycetemcomitans (33384, 43717 and 43718) or T. denticola (35405, 33521 and 35404). The PCR assay may be used to rapidly detect the presence of periodontal pathogens in the future.

Current concepts in diagnosis and treatment of periodontitis

This article describes some areas of periodontal research and current opinions regarding detection of disease progression, as well as risk indicators and risk factors associated with disease progression. Longitudinal probing of periodontal attachment level is considered the gold standard for detection of disease activity although there are problems with this concept. Digital subtraction radiography can assist in the detection of minor changes of alveolar bone height and density. Risk factors such as composition of subgingival plaque and gingival crevicular fluid, as well as the effect of smoking are discussed. Adjunctive treatment with both antibiotics and nonsteroidal anti-inflammatory drugs, systemic or local, seems to be helpful in some forms of disease. Immunization to prevent colonization of tooth surfaces and pockets by periodontal pathogens does not seem to be feasible in the near future.

Prevalence of 6 putative periodontal pathogens in subgingival plaque samples from Romanian adult periodontitis patients

The aim of the present study was to determine by standard cultivation procedures the detection frequencies of Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, Actinobacillus actinomycetemcomitans, Bacteroides forsythus, and Capnocytophaga species as well as various enteric rods in subgingival plaque samples form Romanian adult periodontitis patients. DNA probe analysis (Affirm DP Microbial Identification Test) was also used, parallel to cultivation, to identify P. gingivalis, A. actinomycetemcomitans, and B. forsythus, in deep (> or = 6 mm) and intermediate (4-5 mm) pockets in some of the subjects investigated. Paper points were used to sample 86 deep pockets in 36 patients and 27 intermediate pockets in 9 of the 36 patients. The chi 2 test was used to test for significance of differences between results obtained by cultivation and DNA analysis in both intermediate and deep pockets. P. gingivalis was recovered in a high percentage of the patients (75.8%) and sites (63.6%) examined, followed by P. intermedia, F. nucleatum, and A. actinomycetemcomitans, respectively. Capnocytophaga species were present in almost all subjects. Enteric rods were recovered in 61.1% of the patients and 55.8% of the sites. Except for this high prevalence of enteric rods, the present group of patients had the periodontal species monitored in %s similar to those commonly perceived in the West. The Affirm DP Test and cultivation showed poor correlation in detecting P. gingivalis, A. actinomycetemcomitans, and B. forsythus. The cultivation prevalence of P. gingivalis and P. intermedia in deep pockets was similar to their prevalence in intermediate ones. Overall, the prevalence of the periodontal pathogens investigated in the present Romanian periodontitis patients is similar to what has been revealed in matching Norwegian and other Western periodontitis patient populations. The high prevalence of enteric rods in the Romanian patients may have been an artifact resulting from prolonged transport of the samples in VMGA III.

The effect of initial periodontal therapy on salivary platelet-activating factor levels in chronic adult periodontitis

Platelet-activating factor (PAF), a potent phospholipid inflammatory mediator, is increased in the mixed saliva of subjects with periodontal disease and correlates with the extent of oral inflammation. The present study was designed to provide a longitudinal evaluation of the effect of initial periodontal therapy (home care instruction, prophylaxis, and scaling/root planing) on salivary PAF levels in chronic adult periodontitis patients (n = 15). Mixed saliva was collected prior to, during, and after initial therapy and was utilized to assess PAF levels after lipid extraction and fractionation as well as to histologically assess the number of polymorphonuclear leukocytes (PMN). PAF activity was determined in bioassay relative to authentic PAF (1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine; 16:0-alkyl-PAF). Initial salivary PAF levels (12.1 +/- 2.8 pmole equivalents of 16:0-alkyl-PAF/ml saliva; mean +/- SE) decreased following supragingival plaque control (9.6 +/- 2.4) and were further reduced following scaling and root planing (5.7 +/- 1.4). In parallel, salivary PMN levels were significantly reduced and clinical estimates of periodontal disease were significantly improved; i.e., there was a decrease in the percentage of sites with both bleeding on probing (from 46.1 +/- 4.6% of sites at pretreatment to 25.9 +/- 2.6% after scaling and root planing) and probing depths > or = 4 mm (from 16.7 +/- 1.9% of sites to 10.3 +/- 1.2%). Thus, initial periodontal therapy reduced salivary PAF levels in concert with improvements in clinical estimates of marginal and submarginal periodontal inflammation suggesting that PAF may participate in inflammatory events during periodontal tissue injury and disease.

Clinical and microbiological effects of controlled-release locally delivered minocycline in periodontitis

The clinical efficacy of minocycline in a subgingival local delivery system was evaluated alone (M) or as an adjunct to scaling and root planing (M + SRP), in comparison to scaling and root planing (SRP) or to no subgingival treatment (NoTx) in adult periodontitis. Fifty-one adult patients with > or = 7 mm periodontal pockets demonstrating the presence by culture of Porphyromonas gingivalis (Pg), Prevotella intermedia (P(i)), or Actinobacillus actinomycetemcomitans (Aa) were randomized into one of the above 4 treatment groups. All sites > or = 5 mm in the most diseased quadrant in each patient received the therapy. Other quadrants were not treated. All patients received standardized oral hygiene instructions at the beginning of the study. At 0, 1, 3 and 6 months following therapy the 7 mm experimental sites were evaluated for selected periodontal pathogens by DNA probe analysis. At these same time points, the plaque index, gingival index, and bleeding on probing were evaluated as well as probing depth and relative clinical attachment level which were assessed by means of an automated probe. Probing depth reduction with M + SRP was significantly greater than all other groups at one month and significantly greater than NoTx and SRP at 3 months. There were no differences in probing depth reduction among groups at 6 months. At 6 months the gain in clinical attachment level was significantly greater for SRP than for either the NoTx or M groups. The prevalence of Pg decreased significantly in the M and M + SRP groups at one month.(ABSTRACT TRUNCATED AT 250 WORDS)

Direct detection of Porphyromonas gingivalis in Macaca fascicularis dental plaque samples using an oligonucleotide probe

Oligonucleotide probes complementary to the hypervariable regions of the 16S rRNA of Porphyromonas gingivalis, and previously shown to specifically identify human P. gingivalis strains to the species level, were tested for their ability to recognize P. gingivalis from nonhuman primates (Macaca fascicularis), either as distinct isolates or in subgingival dental plaque. The 32P-labeled probes hybridized with all 147 monkey isolates identified as P. gingivalis by morphology and biochemistry, but did not hybridize with any of the 331 isolates representing 17 genera of bacteria unrelated to P. gingivalis, or to the more closely related P. endodontalis and P. asaccharolytica. This corresponds to sensitivities and specificities of 100%. Of 76 M. fascicularis plaque samples, P. gingivalis was detected by probe and culture in 67. Of 26 human plaque samples taken from separate individuals free of periodontal disease, 23 failed to demonstrate P. gingivalis by probe or culture. The results of the combined 102 monkey and human plaque samples indicate that, when compared to culture as the "gold standard," the P. gingivalis probe had a sensitivity of 96%, a specificity of 87%, and an overall agreement with culture of 93%. These results reveal that the oligonucleotide probes used to identify P. gingivalis are specific for this organism, and give results comparable to culture methods for detecting the presence of P. gingivalis in M. fascicularis dental plaque.