Comparison of Arbitrarily Primed Polymerase Chain Reaction and Ribotyping for Subtyping Actinobacillus actinomycetemcomitans

This study investigated the compatibility of arbitrarily primed polymerase chain reaction (AP-PCR) and ribotyping in the characterization of Actinobacillus actinomycetemcomitans , a major pathogen in the mixed anaerobic microflora of human periodontitis. AP-PCR was performed directly on lysed bacterial colonies using a random-sequence 10-base oligonucleotide primer. Ribotyping was carried out by using purified bacterial chromosomal DNA digested with BglI. DNA fragments were separated electrophoretically, blotted onto a nylon membrane and hybridized with the plasmid pKK3535 containing the rRNA operon of Escherichia coli. The two genetic methods were evaluated on isolates from single individuals and from family members. Twelve AP-PCR types and 47 ribotypes were distinguished among 76 A. actinomycetemcomitans isolates of different serotypes. AP-PCR typing and ribotyping gave compatible results in 18 of 20 comparisons. Although AP-PCR detected less genetic heterogeneity in A. actinomycetemcomitans than ribotyping, the rapid and relatively simple AP-PCR technique seems to be sufficiently discriminative to be used in large scale epidemiological studies which preclude the application of the more laborious ribotyping technique.

Actinobacillus actinomycetemcomitans genotypes in relation to serotypes and periodontal status

Actinobacillus actinomycetemcomitans is prevalent in periodontitis but is found in some periodontally healthy individuals as well. The arbitrarily primed polymerase chain reaction (AP-PCR) was used to fingerprint clinical A. actinomycetemcomitans isolates of different serotypes to determine the association between individual clonal types and periodontal conditions. Fifteen different AP-PCR genotypes were distinguished among 93 A. actinomycetemcomitans isolates from 86 uncohabiting individuals with adult periodontitis, localized juvenile periodontitis or no periodontal destruction. The 3 most common AP-PCR genotypes accounted for 68% of the isolates. Seven of the remaining AP-PCR genotypes were found only in periodontitis. The isolates of a given AP-PCR genotype usually belonged to the same serotype. The distribution of the AP-PCR genotypes among serotype b isolates seemed to differ among the subject groups. The results revealed a major genetic dissimilarity between A. actinomycetemcomitans serotypes and suggested a relationship between some A. actinomycetemcomitans clones and periodontal disease.

Microbiologic and clinical study of polytetrafluoroethylene membranes for guided bone regeneration around implants

This study determined the microbiota of the mucosa- and implant-facing parts of expanded polytetrafluoro ethylene augmentation material, and the influence of major periodontopathogens on the healing process associated with guided bone regeneration around dental implants. Seventeen patients with nine dehiscence and eight extraction defects were studied. Prior to surgery and at membrane removal, microbial morphotypes, total viable counts, and the occurrence of selected microbial species were examined by phase-contrast microscopy, nonselective and selective cultures, and DNA probes. Nine sites with submerged barrier membranes throughout the 9-month study were free of cultivable microorganisms and experienced significantly more osseous healing than eight sites with prematurely exposed membrane. Patients with few or no deep periodontal pockets demonstrated significantly fewer residual osseous defects than patients showing several pockets of increased depths. In addition, patients with prematurely exposed membranes revealed several deep periodontal pockets. Three patients with less than 1 mm of osseous gain yielded either Porphyromonas gingivalis or Actinobacillus actinomycetemcomitans. Peptostreptococcus micros occurred in high proportions in seven of the eight patients with premature membrane exposure and inadequate osseous healing. These findings associate putative periodontal pathogens with unsuccessful guided bone regeneration. The control of periodontal pathogens in the oral cavity prior to placement of barrier membranes around implants might increase the prognosis of osseous regeneration.

Absence of Helicobacter pylori in subgingival samples determined by polymerase chain reaction

The polymerase chain reaction was used for the detection of Helicobacter pylori from subgingival plaque in 336 periodontitis patients. A pair of primers derived from the H. pylori urease gene A served to amplify a targeted 411-bp fragment of genomic DNA. This technique permitted the detection of as few as 60 H. pylori cells. Paper point samples from 3 deep periodontal pockets per patient were immersed in 1 ml of phosphate-buffered saline or distilled water, DNA was solubilized by detergent/protease method, 3.7 microliters or 37 microliters of lysate supernatant was used as template, and the amplification product was analyzed in 1% agarose gel containing ethidium bromide. Each experiment included purified DNA and cell lysate of H. pylori as positive controls. The presence of bacteria in the sample was verified by a primer pair common to prokaryote 16S rRNA. The present study did not reveal the specific polymerase chain reaction amplification product characteristic of H. pylori. We conclude that periodontal pockets do not constitute a natural reservoir for H. pylori.

Utility of radiographic crestal lamina dura for predicting periodontitis disease-activity

The relationship between radiographic crestal lamina dura and periodontitis disease-activity was studied longitudinally in 51 treated adult patients on a systematic 3-month maintenance program. The presence or absence of crestal lamina dura at 1809 interproximal sites was scored from periapical and bitewing radiographs taken at baseline of a 36-month maintenance care period. Semi-annual clinical evaluations by 2 independent examiners were carried out on each patient, with disease recurrence defined as sites revealing a > or = 3 mm increase in probing depth from baseline, or a > or = 2 mm increase in probing depth together with a > or = 2 mm loss of relative attachment level from an occlusal reference stent. Over the 36-month study period, 23 (45%) patients exhibited disease recurrence at 55 (3%) interproximal tooth sites scored for baseline crestal lamina dura. Absence of detectable baseline crestal lamina dura yielded high sensitivity (87-100%), but low specificity (17%) and low positive predictive values (0.8-3.2%), for localized periodontitis recurrence. In contrast, no sites exhibiting an intact baseline crestal lamina dura demonstrated periodontitis recurrence up to 24 months from baseline (100% positive predictive values). Presence of radiographic crestal lamina dura was positively associated with clinical periodontal stability (summary odds ratio for sites = 2.6, P = 0.0004), and negatively associated with periodontitis recurrence (summary odds ratio for sites = 0.4, P = 0.0004), for the 36-month study period. Evaluation of radiographic crestal lamina dura status appears valuable for assessing the risk of periodontitis disease-activity at inter-proximal tooth sites in patients on maintenance care programs.

Mitsuokella dentalis in human periodontitis

The occurrence of Mitsuokella dentalis in periodontitis was determined by culture and DNA probe detection. Subgingival paper-point samples from 480 periodontitis patients were transported in VMGA III, plated onto brucella agar with 5% sheep blood and incubated anaerobically for 7 days. Presumptive identification was based on a colony morphology resembling a water drop and biochemical characteristics. DNA probe detection was performed on paper-point samples using a digoxigenin-labeled cellular M. dentalis DNA probe in a dot-blot assay. Culture and DNA probe identified M. dentalis in 18.1% and in 80.7% of the study patients, respectively. M. dentalis isolates produced phosphatases, galactosidase, glucosidase and acetylglucosaminidase and showed high in vitro sensitivity to metronidazole. This study revealed that M. dentalis is a constituent of the pathogenic microbiota in human periodontitis. The periodontopathic potential of the organism is unknown.

Specific genetic variants of Actinobacillus actinomycetemcomitans correlate with disease and health in a regional population of families with localized juvenile periodontitis

A geographically homogeneous population of 83 subjects, from 21 families with localized juvenile periodontitis (LJP), and 35 healthy control subjects was monitored, over a 5-year period, for the presence of the periodontal pathogen Actinobacillus actinomycetemcomitans. Restriction fragment length polymorphism (RFLP) analysis was used to monitor the distribution of genetic variants of this bacterium in LJP-susceptible subjects that converted from a healthy to a diseased periodontal status. A. actinomycetemcomitans was cultured from 57% of the LJP family members accessioned into the study. Nine of 36 LJP-susceptible subjects, in seven families, developed signs of periodontal destruction. All but one of these conversion subjects harbored A. actinomycetemcomitans. Bacterial variants representative of a single RFLP group (II) showed the strongest correlation with conversion (P < 0.002). Six of nine conversion subjects were infected with A. actinomycetemcomitans from this group. RFLP group II variants also prevailed in 8 of 22 probands but were absent in the 35 healthy control subjects. In contrast to the selective distribution of group II variants is diseased individuals, variants belonging to RFLP groups XIII and XIV were found exclusively in the control subjects. Thus, the use of RFLP to type clinical isolates of A. actinomycetemcomitans has resulted in the identification of genetic variants that predominate in LJP and health. These results indicate that studies concerned with the pathogenicity of this bacterium in LJP should be focused on the group II variants.

Molecular detection of Bacteroides forsythus in human periodontitis

The usefulness of a digoxigenin-labeled genomic DNA probe for the detection of subgingival Bacteroides forsythus was examined. In addition, the arbitrarily primed polymerase chain reaction (AP-PCR) was used to delineate the genetic diversity of B. forsythus periodontal isolates. The DNA probe detected 10(3) B. forsythus cells and yielded a strong signal at 10(4) cells. It reacted with B. forsythus ATCC 43037T and 44 clinical isolates and showed no detectable reactivity with 75 strains of 24 other oral microbial species. In comparison to culture, the DNA probe in a dot-blot method demonstrated a sensitivity of 88.8% and a specificity of 38.4% (accuracy, 72.5%). By colony-blotting on primary plates, a sensitivity of 98.1% and a specificity of 53.8% (accuracy, 82.5%) were obtained. B. forsythus was detected in 449 (73.1%) of 614 periodontitis patients. The occurrence of the organism was closely associated with Porphyromonas gingivalis, both species being present in 54.8% and absent in 22.2% of 270 study samples. AP-PCR identified 24 B. forsythus genotypes among 27 test strains. This study demonstrated the utility of a non-radioactive genomic probe for direct detection of B. forsythus in subgingival specimens. The species showed a considerable degree of genetic diversity. DNA analysis may help to determine the role of B. forsythus in periodontal disease and its mode of transmission among exposed individuals.

Clonal analysis of Porphyromonas gingivalis by the arbitrarily primed polymerase chain reaction

Genetic analysis of Porphyromonas gingivalis strains may distinguish between virulent and nonvirulent strains and also may be used to trace individual strains in epidemiological studies. The present study examined the utility of the arbitrarily primed polymerase chain reaction for genotypic fingerprinting of P. gingivalis. DNA was extracted according to conventional methods. Ten-base oligonucleotide primers with arbitrary sequences were used with the polymerase chain reaction to amplify P. gingivalis genomic DNA. The amplification products were analyzed by agarose gel electrophoresis. The primer GACCGCTTGT grouped 73 P. gingivalis strains into 23 genotypes, including 16 genotypes containing a single strain each. The primer AGGGGTCTTG identified 45 different genotypes, 33 of which contained a single strain. P. gingivalis strains ATCC 33277T and 381 belonged to the same genotype. Likewise, strains W50 and W83 were of the same genetic clone. The present study indicates that the arbitrarily primed polymerase chain reaction represents a valuable and easy method for clonal analysis of P. gingivalis.

Microorganisms in polytetrafluoroethylene barrier membranes for guided tissue regeneration

This study examined the microflora in 11 barrier membranes around teeth with furcation involvement or 2 to 3 wall intrabony defects and in 16 membranes around implants with various types of bony defects. Total viable counts and the occurrence of selected microbial species were determined by non-selective and selective culture and by DNA probes. Study sites were examined for probing pocket depth and attachment level. All tooth-associated membranes yielded high levels of microorganisms. 4 of 5 teeth with membranes harboring less than 10(8) organisms gained 3 mm or more in probing attachment, whereas 6 teeth with membranes with more than 10(8) organisms exhibited loss or only small gains in attachment. 3 membranes with high levels of black-pigmented anaerobic rods lost 1 to 2 mm of attachment. Ten implant-associated membranes with no cultivable microorganisms demonstrated a mean probing gain of 4.9 mm. 6 implants with infected membranes only gained an average of 2.0 mm of supportive bone. The present findings underscore the importance of controlling or eliminating periodontal pathogens on barrier membranes in order to gain new attachment.

Comparison of two pressure-sensitive periodontal probes and a manual periodontal probe in shallow and deep pockets

Three periodontal probes--a manual probe and two computerized, pressure-sensitive probes--were studied to determine their relative recording accuracy. In the first part of the study, replicate probing measurements were taken with the three probes at shallow (less than 5 mm) and deeper (greater than or equal to 5 mm) periodontal sites. In the second part of the study, probing depths were determined on all teeth except third molars by the three probing techniques at a single appointment. Mean values between replicate probings for each instrument did not differ statistically, except for duplicate measurements with one of the electronic probes in pockets with depths greater than 5 mm. All three probes demonstrated higher standard deviations with increasing depth, which indicates decreased reproducibility of probing depth measurements. Results of this study suggest that an electronic, pressure-sensitive probe yields more reproducible probing depth measurements than a conventional manual periodontal probe.

Evaluating two methods for fingerprinting genomes of Actinobacillus actinomycetemcomitans

The arbitrary primer polymerase chain reaction (AP-PCR) and Southern blot restriction fragment length polymorphism (RFLP) were used to genotype the periodontal pathogen A. actinomycetemcomitans. Total genomic DNA from 73 strains was extracted by conventional methods. Three random-sequence 10-base oligonucleotide primers were chosen for AP-PCR. The amplified DNA products were separated electrophoretically in a 1% agarose gel containing ethidium bromide and the banding patterns were compared among different strains. For RFLP analysis, DNA was digested with EcoRI, separated on a 0.8% agarose gel and transferred to a nylon membrane. The membrane was probed with a previously characterized 5.2 kilobases (kb) DNA fragment cloned from A. actinomycetemcomitans strain Y4. The probe was labeled with digoxigenin, and hybridized fragments were detected with anti-digoxigenin antibody. AP-PCR produced 4-10 DNA bands in the 0.5-5 kb regions and distinguished 9, 13 or 17 genotypes, depending on the specific primer used. Southern blot RFLP analysis revealed 12 hybridization patterns consisting of 1 or 2 DNA fragments (2-23 kb). The addition of the Southern blot analysis to the AP-PCR analysis gave rise to a total of 30 DNA profiles among the 73 A. actinomycetemcomitans study strains. The results indicate that both AP-PCR and Southern blot analysis are useful in clonal analysis of A. actinomycetemcomitans.

Antimicrobial therapy in periodontics

Cause-related therapy in periodontics is aimed at the reduction or elimination of microbial pathogens. Periodontitis is associated with microflorae which may consist of indigenous, exogenous or superinfecting organisms. In general, periodontal infections due to indigenous organisms (endogenous or commensal infections) are treated by continual reduction of the bacterial load, exogenous infections (true infections) by adjunctive antibiotic therapy and superinfections (opportunistic infections) by a combined approach of conventional therapy and improvement of compromising host or environmental factors. Properly selected single drug, combination drug and serial drug therapies show great promise in the treatment of severe periodontitis

Beta-hemolytic streptococci in advanced periodontitis

The distribution of serotypes of beta-hemolytic streptococci was examined in 718 periodontitis patients. Subgingival samples were obtained with paper points from the 3 deepest lesions in each patient, transported in VMGA III, plated onto brucella agar with 5% sheep blood and incubated anaerobically for 7 days. Serotyping and speciation were performed with Meritec-Strep Beta-Hemolytic Streptococcus Grouping Set and the Analytab 20S Streptococcus System. Beta-hemolytic streptococci were recovered from 33.7% of patients and averaged 10.5% of the total viable counts in culture-positive subjects. The organisms occurred with higher prevalence in patients 35 years or older than in younger patients. The predominant serotypes were F (62.9%), non-typeable (18.1%), B (6.9%), C (6.9%) and G (5.2%). 100% of beta-hemolytic streptococci were sensitive to penicillin, but less than 5% were sensitive to tetracycline, metronidazole or ciprofloxacin. Beta-hemolytic streptococci may contribute to inflammatory periodontal disease and may interfere with healing after therapy.

Campylobacter rectus in human periodontitis

Campylobacter rectus (formerly Wolinella recta) in periodontitis lesions was studied relative to age and sex distribution, relationship to disease-active periodontitis, response to periodontal debridement and in vitro antimicrobial susceptibility. Subgingival C. rectus was collected with paper points, transported in VMGA III and plated onto nonselective enriched brucella blood agar and Hammond's selective medium for C. rectus, both incubated anaerobically. C. rectus was recovered from 80% of 1654 periodontitis patients. Although the organism showed similar age and sex occurrence, its proportional recovery in culture-positive adults was inversely related to increasing age (r = 0.999, P < 0.001). The organism was positively associated (summary odds ratio = 2.95) with disease activity in a 24-month longitudinal study of 93 adult periodontitis patients on maintenance therapy. C. rectus decreased from 8.2% to 0.7% following local periodontal debridement of 20 culture-positive adult periodontitis patients. The organism exhibited high in vitro susceptibility to therapeutic levels of tetracycline hydrochloride, metronidazole, penicillin G and ciprofloxacin. These findings further delineate the epidemiology and potential pathogenic role of C. rectus in human periodontitis.

Evaluation of peri-implant sulcular temperature

Sulcular temperatures were measured on 35 clinically stable and restored osseointegrated dental implants and compared to 50 remaining natural teeth in 9 partially-edentulous adults using the PerioTemp temperature probe (ABIO-DENT, Inc., Danvers, MA USA). Replicate peri-implant sulcular measurements showed a mean difference of 0.1 +/- 0.15 (SD) degrees C. Implant temperatures varied from 0.41 to 3.9 degrees C below sublingual temperatures measured on each patient, and maxillary implants were significantly cooler than mandibular implants (p < 0.001, t-test). A posterior-to-anterior temperature gradient was found in both the maxilla and mandible, with anterior implants significantly cooler than posterior fixtures. No significant differences were found in sulcular temperatures of osseointegrated dental implants and natural teeth located in anatomically-equivalent oral sites. Similarly to natural teeth, sulcular temperature may serve as a valuable diagnostic tool in evaluating dental implant status.

Immune response to Prevotella intermedia in patients with recurrent nonstreptococcal tonsillitis

The role of three oral flora organisms (Prevotella intermedia, Porphyromonas gingivalis, and Actinobacillus actinomycetemcomitans) was investigated in 31 children with recurrent nonstreptococcal tonsillitis. Antibody titers to the three organisms were measured by enzyme-linked immunosorbent assay in the 31 patients, as well as in 32 control patients who had not suffered from recurrent tonsillitis. None of the individuals in either group suffered from periodontal or dental illness. Significantly higher antibody levels to P intermedia were found in the study group as compared to controls (median 91.0 versus 72.5; p = .02). In contrast, the antibody titers to the other two organisms were generally low (less than 0.30), and no difference was found among the two study groups. The elevated antibody levels to P intermedia, a known oral pathogen that is also isolated from most recurrently inflamed tonsils, suggest a pathogenic role for this organism in recurrent tonsillitis.

Utility of Ramfjord index teeth to assess periodontal disease progression in longitudinal studies

The feasibility of using the Ramfjord index teeth to estimate whole-mouth periodontal disease activity was investigated. Whole-mouth examinations were carried out semi-annually over a 36-month period in 98 maintenance patients previously treated for adult periodontitis. Recurrent periodontitis was defined as either a 3-mm or greater probing depth increase from baseline, or a 2-mm or greater probing depth increase together with 2-mm or greater of relative attachment loss measured from a reference stent. Whole-mouth disease activity was compared to Ramfjord index teeth data, with and without adjustment. Adjustment was made by multiplying disease activity rates on Ramfjord index teeth by the ratio formed from the sum of all teeth present over the sum of all Ramfjord index teeth in the study population. Without adjustment, Ramfjord index teeth markedly underestimated subjects with recurrent disease activity when compared to whole-mouth findings. However, with adjustment, the hypothesis that upper and lower limits on whole-mouth incidence of recurrent periodontitis could be estimated from Ramfjord index teeth disease-activity rates were not rejected (P > 0.20, z-test) at any 6-month interval. At 5 of 6 examinations, the % of disease active subjects as determined from whole-mouth evaluations was below the upper limit for disease incidence calculated, with 95% confidence, from point estimates derived from adjusted Ramfjord index teeth data. Partial-mouth examinations with appropriate adjustment of Ramfjord index teeth data may be useful for assessing periodontal disease progression in longitudinal population studies of human periodontitis.

Periodontal disease and dental caries in relation to primary IgG subclass and other humoral immunodeficiencies

22 females and 3 males with primary hypogammaglobulinaemia (n = 6) or IgG subclass deficiencies with (n = 3) or without (n = 16) concomitant IgA deficiency were examined for periodontal disease and dental caries. Only 1 patient showed more tooth loss than that found in the normal Swedish population. 1 patient demonstrated advanced periodontal disease. No patient exhibited more severe dental caries than that of comparable normal Swedes. Microbiological samples from periodontal pockets and saliva showed recovery of potential periodontopathic and cariogenic bacteria within normal ranges. This study could not support the notion that immunodeficient subjects exhibit an increased risk of developing periodontal disease or dental caries.

Periodontal diseases in young individuals

The prevalence and severity of periodontal diseases in young people are significant. Recent progress in understanding the etiology and pathogenesis of periodontal diseases in this group of patients has allowed significant improvement in periodontal classifications. Actinobacillus actinomycetemcomitans characteristically is the major pathogen involved; black-pigmented anaerobic rods and other organisms can also be important. Treatment of periodontitis should focus on meticulous plaque control and eradication of periodontal pathogens, possibly by means of systemic or topical antimicrobial therapies.

Evaluation of a non-radioactive DNA probe for detecting Porphyromonas gingivalis in subgingival specimens

This study compared the ability of a nonradioactive digoxigenin-labeled DNA probe and anaerobic culture to identify subgingival Porphyromonas gingivalis. Total cellular DNA from P. gingivalis ATCC 33277T was labeled using the Genius kit from Boehringer Mannheim Biochemicals. Anaerobic culture was performed using VMGA III transport medium and enriched brucella blood agar. The DNA probe could detect as little as 1000 P. gingivalis cells added to supragingival plaque. Also, the probe could detect P. gingivalis when it was present in proportions too low to be visualized on overgrown bacterial plates. The probe showed no visible reaction with strains of various oral species or with thousands of non-P. gingivalis colonies from plaque samples. VMGA III could maintain the viability of P. gingivalis for up to 6 days, as evidenced by DNA probing of colony blot of subgingival cultures. A total cellular DNA probe for detecting P. gingivalis seems to offer a simple and reliable method of detecting the organism in subgingival specimens.

Enterococci in human periodontitis

Enterococci are potential pathogens in many human body sites. This study determined the subgingival occurrence and the in vitro antimicrobial susceptibility of enterococci in 100 persons with early-onset periodontitis and 545 persons with advanced adult periodontitis. Subgingival microbial samples were collected with paper points, transported in VMGA III and plated onto anaerobic enriched brucella blood agar or selective Enterococcosel agar (BBL Microbiology Systems). Enterococcal speciation was performed using commercial micromethod kit systems. In vitro sensitivity was determined using a commercial kit system and an agar dilution assay. Subgingival enterococci occurred in 1% of early-onset periodontitis patients and in approximately 5% of adult periodontitis patients. Enterococcus faecalis was the only enterococcal species recovered, and all but one isolate belonged to the same biotype. In vitro antimicrobial sensitivity testing revealed subgingival enterococci resistant to therapeutic levels of penicillin G, tetracycline, clindamycin and metronidazole, but relatively sensitive to ciprofloxacin and amoxicillin/potassium clavulanate (Augmentin). Enterococci may populate periodontal pockets as superinfecting organisms and, in heavily infected patients, may contribute to periodontal breakdown.

Peptostreptococcus micros in human periodontitis

Peptostreptococcus micros is a recognized pathogen in medical infections, and its association with progressive periodontitis was examined in this study. P. micros was isolated from paper-point subgingival samples on anaerobic enriched blood agar plates and identified on the basis of cellular and colonial morphology and selected biochemical tests. In a cross-sectional study involving 907 people with advanced adult periodontitis, 127 with early-onset periodontitis, and 12 with localized juvenile periodontitis, P. micros in these patient groups occurred with a prevalence of 58-63%. In culture-positive patients, P. micros averaged 12-15% of total viable counts. P. micros demonstrated similar occurrence and proportional recovery in all age groups. In a longitudinal study of 91 adult periodontitis patients on maintenance therapy, P. micros demonstrated a significantly higher prevalence in disease-active than in disease-inactive patients (47% vs 14%). Mechanical subgingival debridement and 0.12% chlorhexidine pocket irrigation was unable to eradicate subgingival P. micros from 18 of 22 adult periodontitis patients. In vitro antimicrobial susceptibility testing showed P. micros to be sensitive to therapeutic levels of penicillin, clindamycin and metronidazole. Our findings indicate that P. micros is a potential pathogen in adult periodontitis. The methods for its eradication from subgingival sites remain to be determined.