Utility of 5 major putative periodontal pathogens and selected clinical parameters to predict periodontal breakdown in patients on maintenance care

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.

Adjunctive Antimicrobial Therapy of Periodontitis: Long-Term Effects on Disease Progression and Oral Colonization

BACKGROUND

This study assessed the long-term effects of adjunctive antimicrobial therapy on periodontal disease progression and oral colonization.

METHODS

Patients with previously untreated chronic periodontitis and subgingival Actinobacillus actinomycetemcomitans and/or Porphyromonas gingivalis were randomly assigned to subgingival scaling without (control group) or with systemic amoxicillin plus metronidazole and CHX irrigation (test group). Relative attachment levels were determined and subgingival and mucosal plaque samples were taken at baseline, at 10 days (plaque only) and at 3, 6, 9, 12, 18, and 24 months following initial therapy. During maintenance therapy, patients received supragingival debridement only.

RESULTS

After 24 months, the 18 test group patients showed at sites with initial probing depths (PD) > or =7 mm a significantly (P <0.05) higher frequency of 2 mm or more attachment gain (37.3% +/- 4.6%) and lower frequency of attachment loss (7.2% +/- 3.1%) compared to the 17 controls (8.2% +/- 3.9% and 19.1% +/- 13.1%, respectively). Compared to controls, the intraoral prevalence of A. actinomycetemcomitans (up to 18 months) and P. gingivalis (up to 3 months) decreased and that of Eikenella corrodens (at 10 days) increased in test patients (P <0.05). In both treatment groups, the detection frequency of Tannerella forsythensis decreased transiently, while an overall increase was recorded for Treponema ssp.

CONCLUSIONS

Over the 24-month period, a single course of the administered adjunctive antimicrobial therapy led to a relative risk reduction of 62% for attachment loss at deep sites. However, with the exception of A. actinomycetemcomitans, it failed to induce long-term changes in the prevalence profiles of oral colonization.

Analysis of the presence of pathogens which predict the risk of disease at peri-implant sites through polymerase chain reaction (PCR)

The presence of DNA of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia in the peri-implant sulcus samples of 19 partially edentulous patients was analyzed by polymerase chain reaction (PCR) and related to the depth of the peri-implant sulcus, bleeding on probing, and probable risk of disease. Ten of those patients presented a history of periodontal disease and nine of those did not. The DNA amplification of these pathogens was observed in seven samples, of which four were from patients without history of periodontal disease. The results suggest that even when significant inflammatory signs are absent the qualitative detection may indicate risk of peri-implantitis, requiring more strict postoperative control.

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.

Distribution of fimA genotypes of Porphyromonas gingivalis in subjects with various periodontal conditions

Fimbria encoded by the gene fimA is considered one of the main factors in the colonization of the oral cavity by Porphyromonas gingivalis. Allelic variation in fimA led to the classification of strains of P. gingivalis into six genotypes. The occurrence of P. gingivalis was determined by polymerase chain reaction using 16S rRNA primers in 302 subgingival samples obtained from 102 Brazilian subjects exhibiting different periodontal conditions. Distribution of fimA genotypes was assessed in 146 P. gingivalis positive samples by polymerase chain reaction using primers pairs homologous to the different fimA genes. P. gingivalis was detected in 51 of 57 (89.4%) patients with periodontal attachment loss, in six of 20 gingivitis patients (30.0%) and in two of 25 (8.0%) subjects with a healthy periodontium. Variant type II was the only type detected in 53 sites (39.3%), distributed among 19 periodontitis patients (37.3%) and in one patient with no periodontal destruction. Type Ib was the second most prevalent genotype in periodontitis patients (19.6%). Genotype V was not detected in the studied population. Type IV was the most commonly type found among gingivitis patients, either alone or in combination with other genotypes. Multiple genotypes were detected in nine sites (6.1%). A fimA genotype was not identified in 26 sites (17.8%) of 146 sites positive for P. gingivalis, suggesting that other alleles of fimA not yet sequenced may be prevalent in this population. These data demonstrated that P. gingivalis type II strains followed by type Ib are more prevalent in periodontitis patients from a multiracial population in Brazil, suggesting an increased pathogenic potential of these types.

Relationship of Subgingival and Salivary Microbiota to Gingival Overgrowth in Heart Transplant Patients Following Cyclosporin A Therapy

BACKGROUND

Severe gingival overgrowth (GO) is induced in patients taking cyclosporin A (CsA) following organ transplantation. Determining which patient will develop GO is still not possible. The purpose of this study was to establish an association between CsA and gingival overgrowth in heart transplant patients taking into account periodontal and microbiological conditions.

METHODS

Thirty patients (10 female, 20 male; range: 13 to 67 years; mean age: 44.89) undergoing CsA treatment were evaluated using the gingival index (GI), plaque index (PI), probing depth (PD), and clinical attachment level (CAL). Subgingival samples collected from the deepest site of each quadrant and saliva samples were submitted to microbial analysis. All patients had at least 12 teeth. Exclusion criteria were the use of antibiotics and/or having undergone periodontal treatment 6 months prior to the study. Patients were divided in two groups: with gingival (GO+) and without gingival overgrowth (GO-).

RESULTS

There were no statistically significant differences between the GO+ and GO- groups when CsA dosage, time since transplant, GI, PI, PD, and CAL were compared. Microbiological examination of the subgingival samples detected the following microorganisms: Actinobacillus actinomycetemcomitans (23%), Porphyromonas gingivalis (36%), Prevotella intermedia (93%), Fusobacterium sp. (66%), Campylobacter rectus (30%), Micromonas micros (66%), enteric rods (0%), and yeasts (30%). A positive association between M. micros and the GO+ group was found (P < 0.001). Yeasts were detected in 30% of the subgingival and saliva samples.

CONCLUSIONS

Clinical parameters were not sufficient to determine which patients would develop GO. However, colonization by M. micros might play a role in the etiology of GO.

Isolation and characterization of subgingival staphylococci from periodontitis patients and controls

OBJECTIVES

To isolate and characterize subgingival staphylococci from patients with periodontal disease and from periodontally healthy controls, to evaluate the periodontal environment as a potential source for systemic staphylococcal infections.

METHODS

Periopaper strips were used to isolate subgingival staphylococci from 28 patients with chronic periodontitis and 28 periodontally healthy age and sex-matched controls. Staphylococci were identified by microbiological methods and antibiotic resistance profiles determined.

RESULTS

Staphylococci were isolated from 54% diseased subgingival and 43% healthy subgingival sites in over 50% periodontitis patients and from 29% healthy subgingival sites in 54% controls. No significant differences in the frequency of isolation or numbers of staphylococci isolated from diseased and healthy sites were noted. Staphylococcus epidermidis was the predominant oral species. Seventy per cent (115 of 165) of all isolates were penicillin-resistant.

CONCLUSIONS

Subgingival staphylococci are present in both periodontitis patients and controls. In periodontitis there is an increased risk of bacteraemia because of the increased dentogingival surface area. The dental and periodontal health of patients at risk from haematogenous infections should therefore be maintained at a high level. Antibiotic resistance profiles of the oral staphylococcal isolates suggest that amoxicillin may no longer be a suitable antibiotic for prophylaxis against systemic infections such as prosthetic valve endocarditis.

Clinical effects of scaling and root planing in adults infected with Actinobacillus actinomycetemcomitans

The periodontal pathogen Actinobacillus actinomycetemcomitans can frequently be isolated from subgingival plaque of adults with chronic inflammatory periodontal disease and individuals with plaque-induced gingivitis. Problems with the persistence of the organism after thorough debridement of root surfaces have been reported. In the present study clinical effects of the hygienic phase of periodontal therapy in ten adult patients with moderate or advanced periodontitis harbouring A. actinomycetemcomitans were analysed. Since proper analysis of highly correlated data within a given patient is crucial for appropriate interpretation, a major objective of this study was to compare the results of different models derived from logistic regression of clinical and microbiological factors on gain or loss of clinical attachment under different assumptions. Subgingival samples from every tooth present were obtained before and 6 weeks after thorough subgingival scaling, and selectively cultivated for the organism. A relevant gain of clinical attachment of 2 mm or more was observed at a total of 36% of periodontitis sites after scaling. Overall, loss of attachment of 2 mm or more was observed at 8% sites. Most loss occurred at sites with gingival enlargement (15%), whereas 3% periodontitis sites lost 2 mm or more. In multivariate analyses erroneously assuming either independence of data or correctly considering the correlated structure of observations attachment gain was mainly associated with deep probing depths at the outset. Presence or absence of A. actinomycetemcomitans before or after therapy was not included into the periodontitis models. Also, loss of attachment of 2 mm or more after subgingival scaling was not influenced by the organism. A direct comparison of the results obtained with both approaches of logistic regression may be helpful in the assessment of the influence of the magnitude of correlation of the data on the regression coefficients.

Topical and systemic antibiotics in the management of periodontal diseases

Both systemic and topical antibiotics are increasingly used in the management of periodontal infections. Whilst these drugs are used mostly on an empirical basis, some contend that rational use of antibiotics should be the norm due to their wide abuse and consequential global emergence of antibiotic resistance organisms. Here we review the rationale and principles of antimicrobial therapy, treatment goals, drug delivery routes and various antibiotics that are used in the management of periodontal diseases. The pros and cons of systemic and local antibiotic therapy are described together with practical guidelines for their delivery. The available data indicate, in general, that mechanical periodontal treatment alone is adequate to ameliorate or resolve the clinical condition in most cases, but adjunctive antimicrobial agents, delivered either locally or systemically, can enhance the effect of therapy in specific situations. This is particularly true for aggressive (early onset) periodontitis, in patients with generalised systemic disease that may affect host resistance and in case of poor response to conventional mechanical therapy. Locally delivered antibiotics together with mechanical debridement are indicated for non-responding sites of focal infection or in localised recurrent disease. After resolution of the periodontal infection, the patient should be placed on an individually tailored maintenance care programme. Optimal plaque control by the patient is of paramount importance for a favourable clinical and microbiological response to any form of periodontal therapy.

Microbiological diagnostic testing in the treatment of periodontal diseases

A variety of microbiological diagnostic tests are available for clinicians to use for evaluation of patients with periodontal disease. Each one has its own unique set of advantages and disadvantages, and probably the most useful information for the clinician can be obtained using a combination of the various analytic methods. The tests appear to have their greatest utility when used on patients with chronic or aggressive periodontitis who do not respond favorable to conventional mechanical therapy. The major limitation of all microbiological tests is that the information obtained is relevant to the site sampled, and may not be representative of the microflora of the entire dentition. However, since it is often only specific sites that do not respond to initial therapy, knowing the constituents of the microflora that populate these sites is clinically relevant.

Microbial Identification in the Management of Periodontal Diseases. A Systematic Review

BACKGROUND

Our understanding of the complexity of the oral microbiota continues to improve as new technologies, such as the analysis of 16S rRNA bacterial genes, are utilized. Despite the difficult of cataloguing all microorganisms and determining their pathogenic potential, some species, mostly members of the resident oral microbiota, have been identified as likely periodontal pathogens. However, for microbial diagnosis to be of value, it needs to affect disease diagnosis and/or treatment planning as well as result in superior treatment outcomes and/or provide an economic benefit to the patient.

RATIONALE

The purposes of this systematic review were to determine if microbial identification influences periodontal patient management and whether treatment outcomes are better compared to patients whose treatment plans are developed without this information.

FOCUSED QUESTION

In patients with periodontal diseases, does microbial identification influence patient management compared to treatment prescribed without this information?

SEARCH PROTOCOL

The MEDLINE database was searched for clinical studies in English from 1991 through 2002 by 2 investigators. Hand searches were performed on the Journal of Clinical Periodontology, Journal of Periodontology, Journal of Periodontal Research, Oral Microbiology and Immunology, and Periodontology 2000. In addition, directors of diagnostic laboratories were contacted about unpublished data.

SELECTION CRITERIA

INCLUSION CRITERIA

Articles in which bacterial identification influenced patient treatment were preferred as were those reporting longitudinal data demonstrating a direct relationship between the presence or absence of certain bacteria and subsequent alterations in clinical variables. Because of the limited number of studies, all articles, including case reports, were considered.

EXCLUSION CRITERIA

Review articles without original data were excluded, although references were examined for possible inclusion. Articles reporting data showing associations between certain microorganisms and disease or health that did not affect treatment were excluded. Clinical trials testing antibacterial agents for their ability to enhance mechanical debridement were not included since bacterial identification had little effect on drug selection or experimental group assignment. Articles dealing with implants rather than natural teeth were omitted. DATA ANALYSIS AND COLLECTION: The heterogeneity of the published data precludes any meaningful pooling of data or meta-analysis. The pertinent literature, including relevant variables of plaque, gingivitis, and bleeding on probing scores; probing depth; clinical attachment level; number of lost teeth; and microbial changes; and patient-centered outcomes including decrease in morbidity, reduced need for surgery, and duration and cost of treatment are summarized.

MAIN RESULTS

1. There was a lack of articles with a high evidence rating; most pertinent articles were either case reports or case series without controls. 2. Because reports were heterogeneous regarding study design, patient selection, and data collection, meta-analysis was not feasible and results are summarized in tabular format. 3. This report is based on a total of 24 studies, representing a total patient population of approximately 835. 4. Thirteen studies reported on microbiological identification as an aid in treatment planning. 5. Eleven studies reported a differential clinical response depending on the detection or lack of detection of specific organisms.

REVIEWERS' CONCLUSIONS

1. The published material suggests that microbiological monitoring may be useful in management of selected patients who do not respond to standard therapy. 2. Some practitioners consider microbial identification a valuable adjunct to managing patients with certain forms of periodontitis, although there is a lack of strong evidence to this effect. 3. Additional research is needed to address this issue.

Periodontitis as an infectious disease: specific features and their implications

Periodontitis may be viewed as an infectious disease with a number of specific characteristics. Pathogens of the subgingival microbiota can interact with host tissues even without direct tissue penetration. Hence, antimicrobial agents must be available at a sufficiently high concentration not only within the periodontal tissues, but also outside, in the environment of the periodontal pocket. The subgingival microbiota accumulate on the root surface to form an adherent layer of plaque with the characteristics of a biofilm. Several mechanisms, such as diffusion barriers, and selective inactivation of agents lead to an increased resistance of bacteria in biofilms. Mechanical supragingival plaque control is indispensable to prevent the re-emergence of periodontal pathogens and the re-establishment of a biofilm in treated sites. Since specific features have important implications for the use of antimicrobial agents in periodontal therapy, extrapolations from experiences made in the therapy of other infections are only partially valid. The ultimate evidence for the efficacy of systemic or local chemotherapy must be obtained from treatment studies in humans with adequate follow-up.

Supportive periodontal care: the effect of periodic subgingival debridement compared with supragingival prophylaxis with respect to clinical outcomes

BACKGROUND

The programme of supportive periodontal care (SPC) is essential to the long-term stability of patients with chronic periodontitis. The clinical strategy for SPC is often determined according to 'clinical needs' of the patient and is thus determined by clinical observation and individual decision-making rather than being based on the best available clinical evidence.

OBJECTIVE

To evaluate the effectiveness of supragingival prophylaxis vs. sub-gingival debridement for SPC following the treatment of chronic periodontitis.

SEARCH STRATEGY

Computerized for Medline and the Cochrane Oral Health Group Specialty Trials Register. Hand searching of the Journals of Clinical Periodontology, Periodontal Research and Periodontology. Reference lists from relevant articles were scanned and the authors of eligible studies were contacted to obtain additional information.

SELECTION CRITERIA

Studies were selected if they were designed as a prospective clinical trial in which patients with chronic periodontitis had followed a programme of SPC, which included at least one of the regimens of interest in part of the mouth, for a minimum of 12 months.

DATA COLLECTION AND ANALYSIS

Information regarding methods, patients, interventions (SPC), outcome measures and results were extracted independently, in duplicate, by two reviewers (P.A.H., G.McC.). Absent data were recorded as such and incomplete data were sought from the researchers wherever possible.

RESULTS

In all, 28 papers were identified by the manual and electronic searches; 11 papers were eligible for inclusion. Only one study reported a direct comparison of the two SPCs of interest. The data were reported as mean changes in probing depth and attachment level between baseline and the 12-month follow-up point. For coronal scaling DeltaPD = 0.59 mm [0.13], DeltaAL = -0.13 mm [0.19]. For subgingival debridement DeltaPD = 0.37 mm [0.15], DeltaAL = -0.14 mm [0.18]. There were no significant differences between the SPC regimens. The weighted mean DeltaPD [95% confidence intervals] for the five additional studies that reported supragingival prophylaxis as the SPC regimen was 1.15 mm [-0.17, 2.38]. The weighted mean DeltaPD [95% confidence intervals] for the four studies that reported subgingival debridement as the SPC regimen was 0.56 mm [0.37, 1.47]. The difference between the SPC treatments for the mean DeltaPD is therefore 0.23 mm. The confidence interval for the combined studies was very wide [0.37, 1.47] and very little additional information is gained unless some strong assumptions are made about the comparability of the populations from which the samples are drawn. Such an assumption was not considered appropriate. The weighted mean DeltaAL [95% confidence intervals] for the six additional studies that reported supragingival prophylaxis as the SPC regimen was 0.18 mm [-0.38, 0.74]. The weighted mean DeltaAL [95% confidence intervals] for the six additional studies that reported supragingival prophylaxis as the SPC regimen was 0.50 mm [0.11, 0.89]. The difference between the SPC treatments for mean DeltaAL is 0.32 mm. The confidence interval [-0.36, 1.00] is very wide and the data from the additional studies provide little extra information than that reported in the one study that compared the treatments directly.

CONCLUSION

It is not possible to make any firm recommendations regarding clinical practice based on the crude meta-analysis and the review of these 11 studies. The best available evidence indicates that SPC regimens of supragingival prophylaxis and subgingival debridement are comparable with respect to the clinical outcomes of probing depth and attachment levels at 12 months post non-surgical treatment.

Can presence or absence of periodontal pathogens distinguish between subjects with chronic and aggressive periodontitis? A systematic review

OBJECTIVES

The purpose of this study was to determine to what extent the presence or absence of periodontal pathogens can distinguish between subjects with chronic and aggressive periodontitis.

MATERIAL AND METHODS

A systematic review of cross sectional and longitudinal studies providing microbiological data both from patients with chronic periodontitis (ChP) and aggressive periodontitis (AgP) at a subject level. Strict inclusion criteria were applied. The presence or absence of five microorganisms was selected as primary study parameters: Actinobacillus actinomycetemcomitans (AA), Porphyromonas gingivalis (PG), Prevotella intermedia (PI), Bacteroides forsythus (BF), and Campylobacter rectus (CR).

RESULTS

The presence or absence of AA could be evaluated in 11 papers. In seven papers the presence or absence of PG could be analysed. Subject specific data on PI were available from six studies. Two studies could be used regarding the presence or absence of BF, and two regarding CR. Sensitivity and specificity of every microbiological test were individually calculated for each selected study, assuming that the clinical diagnosis of AgP or ChP was the true status the tests attempted to detect. AgP was considered to be the condition of interest and ChP was considered equivalent to 'non-AgP'. Receiver Operator Characteristic (ROC) diagrams were constructed using these data. ROC diagrams indicated the limited discriminatory ability of all of the test parameters to identify subjects with AgP. An additional assessment showed that the highly leukotoxic variant of AA was uniquely associated with patients suffering from aggressive periodontitis. However, in a high proportion of patients diagnosed with AgP the presence of this variant could not be detected.

CONCLUSION

The presence or absence of AA, PG, PI, BF or CR could not discriminate between subjects with AgP from those with ChP.

Local antibiotic therapy guided by microbiological diagnosis

BACKGROUND

The aim of this study was to determine the distribution patterns of Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in periodontitis patients after standard mechanical periodontal therapy, and to evaluate the effect of additional local antibiotic therapy, given to all teeth with cultural evidence of these bacteria.

METHODS

17 patients were included. 852 separate subgingival microbial samples were taken from the mesial and distal aspect of every tooth in 17 subjects at baseline. 46 of these samples, from 10 positive subjects, showed cultural evidence for P. gingivalis. 82 samples, from 5 subjects, were A. actinomycetemcomitans-positive. Three subjects showed no evidence for persistence of A. actinomycetemcomitans or P. gingivalis. In the other 14 subjects, all A. actinomycetemcomitans- or P. gingivalis-positive teeth were treated with tetracycline fibers (ACTISITE(R)). Sub-gingival microbial samples were again taken from two sites of every tooth, 1 month after fiber removal. 89% of the initially P. gingivalis-positive sites were now negative, but 16 previously negative sites now tested positive. 77% of the initially A. actinomycetemcomitans-positive sites were now negative, but 5 previously negative sites now tested positive. The teeth with persisting P. gingivalis or A. actinomycetemcomitans were again treated with fibers. Two sites of every tooth were once more sampled after 1 month. At this time, 5 subjects still showed cultural evidence of P. gingivalis at a total of 19 sites, and 4 subjects were positive for A. actinomycetemcomitans in a total of 27 sites. These 9 patients were finally submitted to systemic antibiotic therapy (3 x 250 mg metronidazole plus 3 x 375 mg amoxicillin/d for 7 days). Despite of all efforts, P. gingivalis was again detected 3 months later in isolated sites in 3 subjects, and A. actinomycetemcomitans could be cultivated from one single site.

CONCLUSIONS

Therapy with tetracycline fibers guided by microbiological diagnosis effectively reduced P. gingivalis and A. actinomycetemcomitans locally, but was unable to completely eradicate the target organisms. Additional systemic antibiotic therapy further reduced P. gingivalis and A. actinomycetemcomitans. The observed persistence patterns suggest that reemergence of A. actinomycetemcomitans was due to recolonization, whereas the strikingly reproducible local reemergence of P. gingivalis in some sites indicated failed eradication.

Effective, safe, practical and affordable periodontal antimicrobial therapy: where are we going, and are we there yet?

Several important trends are noticeable in the management of periodontal disease. Searching for specific risk factors for periodontal disease permits therapy planning with the intention of doing less for low-risk patients and increasing the preventive and therapeutic modalities for high-risk patients. Also, significant progress in the area of chemotherapeutic development enables dentists to increase the number of periodontitis patients receiving nondisruptive antimicrobial therapy and decreases the need for surgical treatment. Use of anti-infective chemotherapeutic and antibiotic agents has become a specialized and increasingly effective means of preventing and treating destructive periodontal disease. Local care, including subgingival application of some type of antiseptics, is widely accepted. The use of systemic antibiotics is not routine and should be reserved for aggressive and refractory periodontal infections. In general, it is better to be thoroughly familiar with a limited number of drugs and treatment methods and use them properly than to try to master a plethora of antimicrobial therapies. Combating periodontal infections is best accomplished by combined mechanical and chemotherapeutic efforts of the dental professional and the patient. The trend during recent years has been to treat periodontal infections aggressively, employing short-course antimicrobial therapy using a battery of safe and affordable antimicrobial agents, each exhibiting high activity against various periodontal pathogens and administered in ways to concurrently affect pathogens residing in different oral ecological niches, followed by regular maintenance visits having a strong anti-infective emphasis. At the beginning of therapy, patients should be assigned self-help tasks having maximal antimicrobial effectiveness, with a focus on control of the subgingival periodontopathic microbiota. When patients see positive clinical results from their daily oral hygiene efforts, they are motivated to remain active participants in managing their periodontal condition. This article emphasizes anti-infective periodontal therapies that are effective and, when properly administered, are essentially nontoxic; are widely available around the world to dentists as well as to patients; and are acceptable to most patients in terms of methods of application, supporting oral hygiene efforts and financial costs. We believe that, with improved knowledge of the periodontopathic microbiota, with the availability of microbiological tests to identify periodontal pathogens and optimal therapy, with various safe and affordable yet effective antimicrobial agents and therapies and, eventually, with the development of one or more effective vaccines, the future looks very bright for patients at risk for or suffering from destructive periodontal disease.

Comparison of microbial cultivation and a commercial PCR based method for detection of periodontopathogenic species in subgingival plaque samples

OBJECTIVES

Microbiological laboratory procedures are involved in diagnosis and therapy control of progressive and refractory forms of periodontitis. In recent years techniques have been developed based on the detection of nucleic acids. The purpose of this study was to validate the commercially available micro-Dent(R) test which employs probes for A. actinomycetemcomitans, P. gingivalis, P. intermedia, B. forsythus and T. denticola.

METHODS

122 plaque samples obtained from periodontal pockets with various depths from 33 early onset periodontitis (EOP) patients and 15 periodontally healthy subjects were analysed by cultivation and the microDent(R) kit.

RESULTS

Both cultivation and the nucleic acid based assay showed a positive correlation of pocket depth with the frequency and quantity of periodontopathogenic species. T. denticola was found only in pockets > 4 mm in EOP patients. Comparison of the two methods revealed that the microDent(R) kit identified both P. gingivalis and B. forsythus more often than did the cultivation method.

CONCLUSIONS

Nucleic acid techniques should replace cultivation methods as gold standard in microbiological diagnosis of progressive periodontitis. The micro-Dent(R) kit can be recommended for microbiological laboratories analysing subgingival plaque samples.

Periodontal disease as a specific, albeit chronic, infection: diagnosis and treatment

Periodontal disease is perhaps the most common chronic infection in adults. Evidence has been accumulating for the past 30 years which indicates that almost all forms of periodontal disease are chronic but specific bacterial infections due to the overgrowth in the dental plaque of a finite number of mostly anaerobic species such as Porphyromonas gingivalis, Bacteroides forsythus, and Treponema denticola. The success of traditional debridement procedures and/or antimicrobial agents in improving periodontal health can be associated with the reduction in levels of these anaerobes in the dental plaque. These findings suggest that patients and clinicians have a choice in the treatment of this overgrowth, either a debridement and surgery approach or a debridement and antimicrobial treatment approach. However, the antimicrobial approach, while supported by a wealth of scientific evidence, goes contrary to centuries of dental teaching that states that periodontal disease results from a "dirty mouth." If periodontal disease is demonstrated to be a risk factor for cardiovascular disease and stroke, it will be a modifiable risk factor since periodontal disease can be prevented and treated. Since the antimicrobial approach may be as effective as a surgical approach in the restoration and maintenance of a periodontally healthy dentition, this would give a cardiac or stroke patient and his or her physician a choice in the implementation of treatment seeking to improve the patient's periodontal condition so as to reduce and/or delay future cardiovascular events.

Yeasts in periodontal pockets

OBJECTIVES

The presence of yeasts in periodontal pockets has been described in a few studies. The association between yeasts and putative periodontal pathogens is not well described. This study aims at assessing the prevalence of yeasts in periodontal pockets and possible associations with the clinical conditions of the sampled sites and other micro-organisms present.

MATERIAL AND METHODS

2 subject groups form the basis for this study. The 1st comprises results from microbiological samples from periodontal pockets of 128 subjects. The 2nd originates from 126 periodontal patients with untreated pockets. Microbiological identification was performed after cultivation on blood and Sabouraud agar plates, and "checkerboard" DNA-DNA hybridisation.

RESULTS

The prevalence of subjects with yeasts in the pockets was 15.6% and 17.5% in the 2 groups respectively and was inconsistent according to gender. No correlation was found between age and the presence of yeasts. Eubacterium saburreum was weakly correlated with presence of yeasts (r=0.194 p=0.03). Yeasts were rarely found in both samples from the same individual.

CONCLUSIONS

Our results indicate that yeasts can be expected to be present in periodontal pockets in one out of 6 periodontal patients independent of gender and age. Eubacterium saburreum seems to occur frequently together with yeasts.

[Effect of supragingival plaque control on subgingival microflora and periodontal tissues]

The aim of this study was to investigate, clinically and microbiologically, forty-four sites in 11 patients presenting with generalized chronic periodontitis. Plaque Index (PI), Gingival Index (GI), Probing Bleeding (PB), Probing Depth (PD) and Insertion Level (IL) were registered. Samples of subgingival plaque were collected in the same sites for cultivation of anaerobic bacteria and determination of microbiological morphotypes using dark field microscopy. Clinical and microbiological data were recorded on the baseline and 4 weeks after the adoption of a program to control supragingival plaque and calculus. The microbiological analysis categorized the degree of development as follows: 0--not detected, 1--scarce, 2--moderate and 3--abundant. The clinical results at the baseline and on the 28th day were, respectively: PI--1.73 +/- 0.10 and 0.30 +/- 0.08; GI--1.73 +/- 0.08 and 1.41 +/- 0.08; PB--0.91 +/- 0.04 and 0.59 +/- 0.07; PD--6.43 +/- 0.20 and 5.77 +/- 0.25; and IL--6.86 +/- 0.32 and 6.52 +/- 0.34. There was significant decrease in PI, GI, PB and PD. However, the difference in IL was not significant. The relative proportions of the microbial morphotypes observed under dark field microscopy at the baseline and on the 28th day were, respectively: coccoid cells--21.16 +/- 3.77 and 36.00 +/- 4.66; mobile bacillus--44.86 +/- 2.65 and 39.50 +/- 2.64; and total treponemes--24.66 +/- 3.08 and 19.25 +/- 2.75. The cultures presented, at the baseline and on the 28th day, respectively: Prevotella intermedia/nigrescens (Pi/n)--1.36 +/- 0.18 and 0.43 +/- 0.11; Porphyromonas gingivalis--0.48 +/- 0.16 and 0.32 +/- 0.13; Actinobacillus actinomycetemcomitans--0.23 +/- 0.09 and 0.23 +/- 0.10; Fusobacterium nucleatum--0.32 +/- 0.14 and 0.41 +/- 0.13; and peptostreptococci--0.82 +/- 0.19 and 0.54 +/- 0.16. There was a significant increase in the number of coccoid cells and a decrease in the number of treponemes and Pi/n.

Amoxicillin plus metronidazole in the treatment of adult periodontitis patients. A double-blind placebo-controlled study

BACKGROUND, AIMS

The aim of this double-blind, parallel study was to evaluate the adjunctive effects of systemically administered amoxicillin and metronidazole in a group of adult periodontitis patients who also received supra- and subgingival debridement.

METHODS

49 patients with a diagnosis of generalised severe periodontitis participated in the study. Random assignment resulted in 26 patients in the placebo (P) group with a mean age of 40 years and 23 patients in the test (T) group which had a mean age of 45 years. Clinical measurements and microbiological assessments were taken at baseline and 3 months after completion of initial periodontal therapy with additional placebo or antibiotic treatment. Patients received coded study medication of either 375 mg amoxicillin in combination with 250 mg metronidazole or identical placebo tablets, every 8 hours for the following 7 days.

RESULTS

At baseline, no statistically significant differences between groups were found for any of the clinical parameters. Except for the plaque, there was a significantly larger change in the bleeding, probing pocket depth (PPD) and clinical attachment level (CAL) in the T-group as compared to the P-group after therapy. The greatest reduction in PPD was found at sites with initial PPD of > or = 7 mm, 2.5 mm in the P-group and 3.2 mm in the T-group. The improvement in CAL was most pronounced in the PPD category > or = 7 mm and amounted to 1.5 mm and 2.0 mm in the P- and T-groups, respectively. No significant decrease was found in the number of patients positive for any of the test species in the P-group. The number of patients positive for Porphyromonas gingivalis, Bacteroides forsythus and Prevotella intermedia in the T-group showed a significant decrease. After therapy there was a significant difference between the P- and the T- group in the remaining number of patients positive for P. gingivalis, B. forsythus and Peptostreptococcus micros. 4 subgroups were created on the basis of the initial microbiological status for P. gingivalis positive (Pg-pos) and negative patients (Pg-neg) in the P- and the T-groups. The difference in reduction of PPD between Pg-pos and Pg-neg patients was particularly evident with respect to the changes in % of sites with a probing pocket depth > or = 5 mm. This % decreased from 45% at baseline to 23% after treatment in the Pg-pos placebo subgroup and decreased from 46% to 11% in the Pg-pos test subgroup (p < or = 0.005). In contrast, the changes in the proportions of sites with a probing pocket depth > or = 5 mm in the Pg-neg placebo and Pg-neg test subgroup were similar, from 43% at baseline to 18% after treatment versus 40% to 12% respectively.

CONCLUSIONS

This study has shown that systemic usage of metronidazole and amoxicillin, when used in conjunction with initial periodontal treatment in adult periodontitis patients, achieves significantly better clinical and microbiological results than initial periodontal treatment alone. Moreover, this research suggests that especially patients diagnosed with P. gingivalis benefit from antibiotic treatment.

Persistent presence of Bacteroides forsythus as a risk factor for attachment loss in a population with low prevalence and severity of adult periodontitis

BACKGROUND

Previous longitudinal studies investigating the role of microorganisms in periodontitis have focused on subjects with a high prevalence and severity of disease. The complex profile of microbial species in severe cases of periodontitis might not allow us to differentiate which bacterial species initiate disease or which species simply proliferate after disease progression. This prospective longitudinal study followed a group of 205 subjects who showed a low prevalence and severity of adult periodontitis, and thus allowed us to monitor early microbiological changes in the development of periodontitis.

METHODS

Subgingival plaque was collected from proximal surfaces of a posterior sextant at 6-month intervals for 2 years. During the monitoring period, 44 subjects had either attachment loss or attachment gain. Using multiplex polymerase chain reaction (PCR), all plaque samples from those 44 subjects were analyzed for the presence of Actinobacillus actinomycetemcomitans, Bacteroides forsythus, and Porphyromonas gingivalis.

RESULTS

Both subjects with attachment loss and those with attachment gain had a high prevalence of these 3 periodontal pathogens. The mere presence of any of the 3 species at a site could not predict future attachment loss at that specific site. However, subjects with a persistent presence of B. forsythus at any site across all visits had 5.3 times higher odds of having at least one site in their mouth losing attachment compared to subjects with occasional or no presence of B. forsythus.

CONCLUSIONS

The persistence of B. forsythus identified subjects at higher risk, but not which specific sites in those subjects would lose attachment.

Efficient antimicrobial treatment in periodontal maintenance care

BACKGROUND

The goal of follow-up care after periodontal therapy is to preserve the function of individual teeth and the dentition, ameliorate symptoms and simplify future surgery or make it unnecessary. Effective follow-up periodontal care depends on early diagnosis and treatment, as well as patient education.

RESULTS

The main determinants of successful periodontal maintenance therapy are dental professionals' ability to combat periodontal infections and patients' compliance with prescribed follow-up care. Mechanical and chemical antimicrobial intervention is the mainstay of preventive periodontal therapy. Chemotherapeutics alone are unlikely to be effective in the presence of subgingival calculus, underscoring the importance of subgingival mechanical débridement. Also, because toothbrushing and rinsing alone do not reach pathogens residing in periodontal pockets of increased depths, oral hygiene procedures should include subgingival treatment with home irrigators or other appropriate self-care remedies.

CLINICAL IMPLICATIONS

When considering possible preventive therapies, dental professionals must weigh the risk of patients' acquiring destructive periodontal disease against potentially adverse effects, financial costs and inconvenience of the preventive treatment. The authors discuss theoretical and practical aspects of follow-up care for patients with periodontal disease. In addition, because it can be both difficult and expensive to control periodontal disease via conventional preventive measures alone, they present a new, simple and more cost-effective antimicrobial protocol for supportive periodontal therapy.

Persistence patterns of Porphyromonas gingivalis, Prevotella intermedia/nigrescens, and Actinobacillus actinomyetemcomitans after mechanical therapy of periodontal disease

BACKGROUND

The aim of this study was to determine the distribution patterns of Porphyromonas gingivalis, Prevotella intermedia/nigrescens, and Actinobacillus actinomycetemcomitans in periodontitis patients after standard mechanical periodontal therapy, and to determine factors increasing the odds to detect these target organisms in treated sites.

METHODS

Eight hundred fifty-two (852) separate subgingival microbial samples were taken from the mesial and distal aspects of every tooth in 17 patients. Target organisms were identified culturally.

RESULTS

The 3 microorganisms showed different persistence patterns: P. gingivalis was detected in a high percentage of subjects (59%), but in a low proportion of sites (5.4%). P. intermedia/nigrescens was detected in all subjects except one, and in 40.6% of the tested sites. Only 5 subjects were A. actinomycetemcomitans positive, but 2 of them showed a very high number of positive sites (44% and 75%, respectively). A highly significant relationship was found between a subject's tendency to bleed upon sampling and the number of P. intermedia/nigrescens-positive sites. A significant portion of the variation in frequency of persisting P. gingivalis could be explained by the frequency of persisting pockets deeper than 4 mm. No similar relationship could be established between clinical parameters and A. actinomycetemcomitans. On a site level, the odds of detecting P. gingivalis increased by a factor of 2.47 (P= 0.0001) for every millimeter of residual probing depth; the odds of detecting P. intermedia/nigrescens increased by a factor of 1.84 (P= 0.0001).

CONCLUSIONS

If, after standard mechanical periodontal therapy, a large number of sites continue to bleed, one may expect an increased number of sites positive for P. intermedia/ nigrescens. If many deep pockets persist, a greater number of P. gingivalis-positive sites can be expected.

Flow cytometry to monitor phagocytosis and oxidative burst of anaerobic periodontopathogenic bacteria by human polymorphonuclear leukocytes

The reduced susceptibility to phagocytosis found among some periodontopathogenic anaerobes may account for the differences between invasive and non-invasive strains. We applied flow cytometry as a powerful tool to analyze and quantify phagocytosis using standardized cultures of oral anaerobes (Porphyromonas gingivalis, Prevotella intermedia, P. nigrescens, Capnocytophaga gingivalis, C. ochracea, C. sputigena, Fusobacterium nucleatum and Peptostreptococcus micros) and heparinized whole blood. Bacteria were labeled by a fluorescein-methylester and their esterase activity, resulting in green fluorescence. Ingested bacteria could be detected easily and quantified by a shift towards green fluorescence in the PMNL population involved and a concomitant decrease in the bacterial population. Furthermore, the oxidative burst of PMNLs was detected in parallel assays using the dye DHR123 which becomes fluorescent upon oxidation during the oxidative burst process. We found a great diversity in phagocytosis susceptibility determined by estimating the portion of phagocytosing PMNLs, ranging from 10.6% (strain W83) to > 99.4% (e.g. ATCC 33277T) in P. gingivalis and from 15.9% (strain MH5) to > 95% (ATCC 33563T) in P. nigrescens. In contrast, almost all P. intermedia strains as well as the representatives of the other anaerobic, putative periodontopathic species tested showed no or only moderate resistance in the phagocytosis assay. Comparison of clinical data of patients and the extent of phagocytosis resistance of the corresponding P. gingivalis strains suggests that this virulence factor may contribute to the clinical outcome.

Additional clinical and microbiological effects of amoxicillin and metronidazole after initial periodontal therapy

The aims of this study were to evaluate the clinical and microbiological effects of initial periodontal therapy (IT) and to determine the additional effects of systemic amoxicillin (Flemoxin Solutab) 375 mg TID plus metronidazole 250 mg TID therapy, in patients with adult Actinobacillus actinomycetemcomitans (Aa)-associated periodontitis in conjunction with either Porphyromonas gingivalis (Pg), Bacteroides forsythus (Bf) and/or Prevotella intermedia (Pi). In addition the adverse effects of the antimicrobial therapy were also documented. A total of 22 patients were enrolled. The deepest, bleeding pocket in each quadrant was selected and at these 4 experimental sites clinical measurements and microbiological testing was carried out at baseline, after (IT), i.e., 21 weeks after baseline, and after antimicrobial therapy (AM), i.e., 35 weeks after baseline. At baseline, the mean plaque index (PI) amounted 0.5, 0.1 after IT and 0.3 after systemic AM. The mean bleeding index decreased from 1.6 to 1.2 after IT and a further decrease to 0.7 after AM was noted. Suppuration was completely eliminated after AM. The mean change of probing pocket depth (PPD) after IT amounted 1.4 mm and was further reduced with an additional mean change of 1.1 mm after medication. Clinical attachment gain was 1.1 mm after IT and an additional 0.9 mm was observed after AM. One of the 22 Aa positive patients and 4 of 17 Pg positive patients became negative for these species after IT. The number of patients with detectable Pi decreased from 16 to 10 after IT. After AM, in comparison to baseline, suppression below detection level for Aa was achieved in 19 out of 22, for Pg in 9 out of 17, for Bf in 13 out of 14, and for Pi in 11 out of 16 patients. By contrast, higher frequencies of Peptostreptococcus micros and Fusobacterium nucleatum were found after AM. On the basis of the microbiological results the study group was separated into 2 subgroups: group A consisted of subjects who had no detectable levels of Aa, Pg, Bf and <5% of Pi after AM. Group B consisted of those who still showed presence of one of these 3 species and/or > or =5% levels of Pi. After AM, group B had significantly higher PI, BI, PPD and CAL scores then group A. It is concluded that group A showed low plaque scores and no detectable periodontal pathogens. This microbiological condition has been associated with a long-term stable periodontium.

Association of oral spirochetes from periodontally healthy sites with development of gingivitis

The purpose of this investigation was to determine whether the presence of selected disease-associated bacteria in health-associated plaque correlated with future gingivitis. Sites of periodontal health were identified in 65 adults. Six months later (recall 1) plaque was collected from sites that remained in periodontal health, and 5 species of specific bacteria and pathogen-related oral spirochetes were detected using monoclonal antibodies in a microscopic assay. Members of the spirochete morphogroup were also identified by phase contrast microscopy. The relationship between site-specific detection of bacteria at recall 1 and development of gingivitis at recall 2 or 3 was evaluated by means of logistic regression using generalized estimating equations, from which odds ratios (OR) were estimated. Significance was conservatively defined as OR > 2.0 and P < 0.05. We found that 488 of 1,424 healthy sites developed gingivitis over the 12-month interval between recall 1 and 3. Only the spirochete morphogroup (OR =2.04; P=0.002) was significantly associated with the transition from health to gingivitis. The association of Treponema socranskii with future gingivitis was higher than expected (OR=2.27), but the relationship was not statistically significant (P=0.163). Campylobacter rectus, Eikenella corrodens, Porphyromonas gingivalis, and pathogen-related oral spirochetes did not correlate well with gingivitis (OR < 2.0). Health-associated plaque from 5 sites contained Treponema denticola, and all 5 sites progressed to gingivitis. An OR could not be calculated because T. denticola was not detected in health-associated plaque from stable healthy sites. These findings indicated that the presence of T. denticola and unidentified spirochetes in health-associated plaque was associated with increased susceptibility to gingival inflammation. Future studies assessing a larger panel of dental plaque microorganisms, with shorter intervals between baseline and follow-up assessment, are necessary to more fully evaluate the association between detection of specific organisms at healthy sites and risk for gingivitis.

Treatment of periodontal disease in older adults

The literature does not indicate that older adults differ from younger individuals in their response to periodontal treatment. However, in older adults, it is more common to find compromised general conditions that may negatively affect the patient's ability to maintain an adequate standard of self-performed plaque control. Although this can be compensated for partly by a carefully designed program for supportive therapy, the prevention and/or elimination of clinical signs of periodontal inflammation may not always be a reachable goal of periodontal therapy in older adults, particularly in those who are frail and functionally dependent. For many patients, a more realistic goal may be the control of disease progression in order to preserve a functional and comfortable dentition throughout life and hence, the decision making process regarding therapeutic levels for the individual patient must include factors such as the amount of remaining periodontal support, the risk for disease progression, demands for oral health and life expectancy.

Periodontitis patient and the spouse: periodontal bacteria before and after treatment

Suspected periodontal pathogens can be transmitted between spouses. The treatment response may be unsuccessful in periodontitis patients, if the spouse harbors these bacteria. The aim of the present 6-month follow-up study was to clarify whether the microbiological treatment outcome of periodontitis patients is related to the detection of suspected periodontal pathogens in the saliva of the spouse. 10 patients with advanced periodontitis and their spouses were included in the study. The patients received mechanical periodontal treatment and 500 mg metronidazole systemically 2x a day for 7 days. The presence of visible plaque, gingival bleeding after probing, suppuration, supragingival and subgingival calculus and pocket depths were assessed at baseline and 1 and 6 months after treatment. Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia/Prevotella nigrescens, Campylobacter rectus and Peptostreptococcus micros were cultured from pooled subgingival samples from the patients and from salivary samples from the spouses at corresponding occasions. Periodontal conditions in the patients improved after treatment as determined by the significantly lower values of clinical variables 1 and 6 months after treatment compared to those at baseline. However, the re-emergence of periodontal bacteria after treatment of the patients was not related to the concurrent detection of the respective bacteria in the saliva of the spouses. In this study design, it seemed that the salivary bacterial load in the spouse was of minor importance for the microbiological treatment outcome of the patient.

Association of oral spirochetes from sites of periodontal health with development of periodontitis

The purpose of this investigation was to determine whether the presence of disease-associated bacteria in health-associated plaque correlated with susceptibility to periodontitis over time. Sites of periodontal health were identified in 65 adults. Six months later (recall 1), plaque was collected from sites that remained in periodontal health, and specific bacteria were detected using monoclonal antibodies in a microscopic assay. The spirochete morphogroup was identified by phase contrast microscopy. The relationship between detection at recall 1 and development of periodontitis over two successive 6-month intervals (recalls 2 and 3) was evaluated by means of logistic regression using generalized estimating equations (GEE), from which odds ratios (OR) were estimated and tested for significance. Significant relationships were defined as those having ORs with P < 0.05. Ninety-three of 1,032 sites developed signs of early periodontitis over the 12-month interval between recall 1 and recall 3. The spirochete morphogroup (OR = 3.13, P < 0.001) and pathogen-related oral spirochetes (PROS) (OR = 3.68, P < 0.001) were significantly associated with healthy sites that developed periodontitis. The association of Treponema socranskii was not significant (OR = 3.62, P = 0.0918). Odds ratios for Campylobacter rectus, Eikenella corrodens, and Porphyromonas gingivalis were less than 2.0 and not significant. Treponema denticola was not detected in health-associated plaque from stable health sites and was detected in only three sites that progressed to periodontitis. These findings indicate that the presence of PROS and some unidentified spirochetes in health-associated plaque is associated with increased susceptibility to periodontitis.

Effects of metronidazole in patients with "refractory" periodontitis associated with Bacteroides forsythus

The aim of the present study was to monitor the microbiological and clinical effects of renewed supra- and subgingival debridement in conjunction with systemic metronidazole therapy (500 mg TID for 7 days) in 27 "refractory" periodontitis patients, culture positive for Bacteroides forsythus and negative for Actinobacillus actinomycetemcomitans. Clinical evaluation included assessment of plaque, bleeding upon probing, probing pocket depth and clinical attachment loss at the deepest, bleeding site in each quadrant. Microbiological evaluation was carried out by anaerobic cultivation of subgingival plaque samples from the same sites. 6 months after renewed debridement and systemic metronidazole (RD+M), a statistically significant improvement of all clinical parameters was observed, except for the plaque index. After RD+M, B. forsythus was suppressed below detection level in 17 of the 27 patients, P. gingivalis in 9 out of 15 patients and P. intermedia in 14 of the 21 patients. Before RD+M, 12 patients harboured simultaneously B. forsythus, P. gingivalis as well as P. intermedia. Out of these, 6 patients were culture negative for the 3 species after therapy and showed the greatest reduction in pocket depth (3.1 mm) and gain of clinical attachment level (2.5 mm). In the treatment of refractory periodontitis, associated with patients culture positive for B. forsythus and negative for A. actinomycetemcomitans, metronidazole can significantly improve the clinical and microbiological parameters.

Occurrence of invading bacteria in radicular dentin of periodontally diseased teeth: microbiological findings

Bacterial invasion in roots of periodontally diseased teeth, which has been recently documented using cultural and microscopic techniques, may be important in the pathogenesis of periodontal disease. The purpose of this investigation was to determine the occurrence and the species of invading bacteria in radicular dentin of periodontally diseased teeth. Samples were taken from the middle layer of radicular dentin of 26 periodontally diseased teeth. 14 healthy teeth were used as controls. Dentin samples were cultured anaerobically. The chosen methodology allowed the determination of the numbers of bacteria present in both deeper and outer part of dentinal tubules, and the bacterial concentration in dentin samples, expressed as colony forming units per mg of tissue (CFU/mg). Invading bacteria was detected in 14 (53.8%) samples from periodontally diseased teeth. The bacterial concentration ranged from 831.84 to 11971.3 CFU/mg (mean+/-standard deviation: 3043.15+/-2763.13). Micro-organisms identified included putative periodontal pathogens such as Prevotella intermedia, Porphyromonas gingivalis, Fusobacterium nucleatum, Bacteroides forsythus, Peptostreptococcus micros and Streptococcus intermedius. These findings suggest that radicular dentin could act as bacterial reservoir from which periodontal pathogens can recolonize treated periodontal pockets, contributing to the failure of therapy and recurrence of disease.