Suppression of the periodontopathic microflora in localized juvenile periodontitis by systemic tetracycline

Metronidazole in the treatment of localized juvenile periodontitis

Systemic metronidazole and tetracycline were compared as adjunctive agents in the treatment of localized juvenile periodontitis (LJP). 27 patients with Actinobacillus actinomycetemcomitans-positive (Aa) LJP were treated with scaling and rootplaning, control of oral hygiene and periodontal surgery if indicated. The patients were randomly divided into 3 equal groups: the 1st group had metronidazole 200 mg x 3 x 10 days, the 2nd tetracycline 250 mg x 4 x 12 days, the 3rd group received no medication and served as a control. 6 patients had periodontal surgery. 4 sites with the most advanced bone loss as determined on radiographs were selected in each subject for test sites. Gingival index, gingival bleeding after probing (GB), probing depth (PD), suppuration, and radiographic bone loss were registered, and subgingival Aa was selectively cultured. GB and PD > or = 4 mm were registered in the whole dentition as well. All parameters were monitored at baseline and at 6 and 18 months after treatment. By the end of the study, Aa was suppressed to below detection level at all test sites only in the metronidazole group, at 17/26 sites (4 patients) in the tetracycline group and at 19/26 sites (6 patients) in the control group. Clinically, all groups showed improvement. In conclusion, metronidazole was more effective than tetracycline in the suppression of Aa and the suppression of Aa appeared to produce better clinical results.

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.

In vitro susceptibilities of Actinobacillus actinomycetemcomitans to a number of antimicrobial combinations

The in vitro susceptibilities of Actinobacillus actinomycetemcomitans to 14 antimicrobial combinations were studied by using the checkerboard titration technique. The results, expressed as the range of the fractional inhibitory concentration indices, were as follows: for metronidazole or its hydroxymetabolite combined with cefixime, 0.2 to 0.6; for moxalactam, 0.2 to 0.6; for penicillin G, 0.3 to 0.6; for tobramycin, 0.8 to 2.0; for erythromycin, 0.8 to 1.7; for ciprofloxacin, 0.2 to 0.6; for tetracycline, 0.8 to 1.2. Our observations indicated that the beta-lactam antibiotics as well as ciprofloxacin act synergistically with both metronidazole and its hydroxymetabolite against A. actinomycetemcomitans. Synergistic interactions were independent of the individual MICs of the antibiotics tested. Erythromycin, tobramycin, and tetracycline combined with either metronidazole or its hydroxymetabolite showed additive to indifferent effects against the five strains of A. actinomycetemcomitans, with the fractional inhibitory concentration indices ranging from 0.8 to 2.0. A. actinomycetemcomitans was found to be highly susceptible to ciprofloxacin (MIC of ciprofloxacin for 90% of strains tested, 0.010 micrograms/ml) and cefixime (MIC of cefixime for 90% of strains tested, 0.8 micrograms/ml). The results indicate that in patients who are allergic to penicillin, cefixime and ciprofloxacin may be useful alternative antibiotics in combination with metronidazole for the treatment of A. actinomycetemcomitans-associated periodontitis.

Comparative study of subgingival microbiological sampling techniques

The presence of specific bacteria in subgingival plaque has been used as an indicator of active periodontal disease. The technique of subgingival sampling may conjecturally influence the identification and enumeration of microorganisms reported. In this study, paper point sampling and scaler sampling are compared. Subgingival samples using both methods were taken from three surfaces in each of 12 patients at the following time points: at each of two appointments one week apart before treatment and at each of two appointments 12 and 13 weeks following treatment. Microbiological analyses were undertaken to determine the total number of colony forming units, the proportions of suspected periodontal pathogens, and the number of spirochetes using phase contrast microscopy. Significantly higher numbers of colony forming units and spirochetes were found for paper point sampling both before and after treatment.

Comparative clinical and microbiological effects of topical subgingival application of metronidazole 25% dental gel and scaling in the treatment of adult periodontitis

The aim of the study was to compare the clinical and microbiological effects of topical application of a metronidazole gel and a single session of subgingival scaling in the treatment of adult periodontitis. An open, randomized controlled clinical study design was employed. Each of 24 subjects received the 2 treatments simultaneously each in 2 randomly selected quadrants of the dentition. The metronidazole, 25% gel was applied subgingivally on days 0 and 7. Scaling was carried out in one quadrant on day 0 and in one quadrant on day 7. Clinical and microbiological examinations were carried out before treatment and on days 21, 49, 91, 133, and 175 of the experimental period. The microbiological analyses included determination of total anaerobically cultivable bacteria, and relative proportions of anaerobes, aerobes, black-pigmented anaerobic Gram negative rods, Actinobacillus actinomycetemcomitans, streptococci, and spirochetes. Both treatments were effective in reducing probing pocket depth and bleeding on probing. Metronidazole tended to be a little better than scaling during the study period and the clinical effects of both treatments persisted during the whole 6 months observation period. Local metronidazole treatment induced a significant and long-lasting shift in the subgingival flora towards a composition more compatible with health and comparable to that obtained by mechanical debridement. Proportions of black pigmented anaerobes including Prevotella intermedia, and the number of spirochetes were significantly reduced after both treatments with a concomitant increase in the proportions of streptococci. While scaling resulted in a statistically significant increase in the proportion of A. actinomycetemcomitans, this was avoided after metronidazole treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum levels of tetracycline during treatment with tetracycline-containing fibers

Four adult patients with at least 8 teeth that had attachment loss of 5 to 10 mm which bled on probing were included in this study. Polymeric tetracycline (TCN) containing fibers were placed and left in the pockets for a period of 10 days. Plasma samples were collected at baseline, 1 hour, 3 hours, 3 days, and 10 days after fiber placement. The mean length of fiber used averaged 187 cm with a range of 160 to 222 cm. The maximum TCN dose per patient averaged 105 mg with a range of 91 to 126 mg producing no detectable serum level greater than 0.1 micrograms/ml. This level was found in 3 of the 4 subjects at 3 hours after fiber placement and in 1 subject at 3 days after fiber placement. Transient and insignificant levels of TCN became available systemically shortly after the placement of multiple fibers. The dose of TCN in each patient was well tolerated and was not associated with any serious adverse effects.

Microbiota associated with residual clefts and neighboring teeth in patients with cleft lip, alveolus, and palate

Twenty patients with residual clefts or pronounced soft tissue grooves, treated for uni- or bilateral cleft lip, alveolus, and palate were included in this study. Ten patients were recalled for dental prophylaxis at regular intervals, 10 patients were not. One microbiologic sample was obtained from the cleft area and two samples from a tooth adjacent to the cleft (sites adjacent and distant to the cleft). Between the recall and the nonrecall group there were notable differences in the presence of anaerobic Gram-negative organisms. Fusobacterium spp., Prevotella melaninogenica, and P. intermedia were more often found in nonrecall patients. While rarely seen in recall patients, spirochetes and motile rods were a common feature of nonrecall patients. The putative periodontal pathogens Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis were not detected in either group. The differences between the recall and the nonrecall groups were more pronounced when the respective samples from teeth were related to each other than when the samples obtained from the clefts were compared. The cleft flora was less complex irrespective of how good maintenance was and resembled the flora of teeth of well-maintained patients. Samples from clefts were never Wolinella positive, and harbored significantly less Capnocytophaga and Actinomyces viscosus than samples from dental sites.

Neutrophil modulation by Actinobacillus actinomycetemcomitans. II. Phagocytosis and development of respiratory burst

Compromised neutrophil function has been found in a number of patients with localized juvenile periodontitis (LJP), although the pathogenic mechanism is unknown. Since infection with Actinobacillus actinomycetemcomitans is frequently found in patients with LJP, we have evaluated in vitro the effect of a bacterial extract of A. actinomycetemcomitans on the development of the respiratory burst by neutrophils. Pre-incubation of neutrophils with bacterial extract increased H2O2 induced by FMLP and zymosan in a dose-dependent fashion. Substitution of FMLP for bacterial extract produced similar results. Moreover, FMLP and bacterial extract had an additive effect on superoxide production following phagocytosis of zymosan. In contrast, bacterial extract significantly decreased PMA-stimulated H2O2, but pre-incubation with FMLP instead of bacterial extract failed to decrease PMA-stimulated H2O2. Bacterial extract did not change the percentage of cells activated by FMLP, opsonized zymosan, or PMA. Heat-treated bacterial extract induced effects similar to non-treated extract. Bacterial extract treated with proteinase K or phenol extraction increased FMLP or zymosan stimulated H2O2 equivalent to non-treated bacterial extract. In contrast, proteinase K or phenol extraction abolished the inhibitory effect of bacterial extract on PMA-stimulated H2O2 production. The bacterial extract component(s) that inhibits PMA-stimulated H2O2 is therefore a protein(s), resistant to 56 degrees C, and is not endotoxin. The partially activated state of PMNs exposed to A. actinomycetemcomitans extract, combined with their reduced ability to respond to a protein kinase C-dependent stimulus, may partially explain the abnormalities noted in LJP patients.

E-test: a new technique for antimicrobial susceptibility testing for periodontal microorganisms

The purpose of the study was to validate the Epsilometer test (E-test) method for antimicrobial susceptibility testing of selected periodontopathic microorganisms using the agar dilution method as a standard. The E-test has been developed to provide a direct quantification of antimicrobial susceptibility of microorganisms. The device consists of a predefined, continuous, and exponential gradient of antibiotic concentrations immobilized along a rectangular plastic test strip. After 48 hours incubation a drop-shaped inhibition zone intersects the graded test strip at the inhibitory concentration (IC) of the antibiotic. Twenty-two subgingival plaque samples from periodontitis sites were plated on trypticase soy agar supplemented with 5% rabbit blood or 5% sheep blood and trypticase soy agar supplemented with vancomycin and bacitracin. A total of 60 strains of key periodontal pathogens (Prevotella intermedia, Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Eikenella corrodens, Campylobacter rectus, and Capnocytophaga) isolated from 22 sites of 12 patients were studied. The antibiotics tested were clindamycin, metronidazole, tetracycline, ciprofloxacin, cefoxitin, and ampicillin at concentrations above and below the achieved blood or gingival crevicular fluid levels. As a standard reference the minimal inhibitory concentrations (MICs) were determined using the agar dilution method. MICs were compared with ICs determined using the E-test method. The results showed an agreement ranging from 67% to 100%; sensitivity ranging from 75% to 100%; predictability ranging from 56% to 100% and specificity ranging from 33% to 96%. The E-test ICs for ampicillin, cefoxitin, and metronidazole against the Gram-negative capnophilic and microaerophilic rods and the black-pigmented anaerobic rods ICs for ampicillin, clindamycin, metronidazole, and tetracycline showed a high percentage of agreement with the agar dilution MICS.(ABSTRACT TRUNCATED AT 250 WORDS)

Neutrophil modulation by Actinobacillus actinomycetemcomitans I. Chemotaxis, surface receptor expression and F-actin polymerization

Localized juvenile periodontitis is an early onset periodontitis, usually localized to molars and incisors. Patients usually present with decreased chemotaxis of systemic neutrophils (PMNs) and infection with Actinobacillus actinomycetemcomitans. The pathogenic mechanisms involved have not been clarified. The purpose of this study was to determine if an extract of A. actinomycetemcomitans could induce changes in PMN chemotaxis similar to those reported in LJP patients. It was demonstrated that the bacterial extract was chemotactic for neutrophils. When neutrophils were pre-incubated with the bacterial extract, chemotaxis toward zymosan-activated serum, FMLP and the bacterial extract was inhibited in two different chemotaxis assays (Boyden chamber and under-agarose). Bacterial extract had no effect on random migration in either assay. Pre-incubation with the extract induced increased expression of CD11b/CD18 (Mac-1), Gp110, and FMLP receptors and increased F-actin polymerization following FMLP or PMA stimulation compared to cells not treated with the extract. Treatment of the bacterial extract with proteinase K or phenol extraction reversed the PMN chemotaxis inhibition activity, but increased significantly the random migration of PMNs. Heating the bacterial extract to 56 degrees C had no effect on its activity. The component(s) in the bacterial extract that inhibits chemotaxis is therefore a protein(s), not sensitive to 56 degrees C, and is not endotoxin. This study suggests that A. actinomycetemcomitans may contribute to the pathogenesis of localized juvenile periodontitis by inhibiting chemotaxis. Interference with chemotaxis by A. actinomycetemcomitans, however, occurs through a mechanism other than inhibition of actin assembly, reduction of CD11b/CD18 or Gp110 expression, or blockage/downregulation of FMLP receptors.

Efficacy of bone-fill favoring treatment on juvenile periodontitis

In this study we evaluated the effect of bone-fill favoring mechanical treatment on the marginal bone level and periodontal pockets of juvenile periodontitis patients. A total of 10 patients (3 men and 7 women) 13-29 yr of age were treated until no gingivitis or periodontal pockets were present. The intensive therapy (3-8 wk) included scaling, curettage and modified Widman flaps. The maintenance therapy comprised 4 recall visits during the first year after therapy and 2-5 visits per year thereafter. The efficacy of the therapy was evaluated by radiologic measurements of bony defects (%) 12 and 16-65 months after the treatment. The results showed a significant improvement both 1 yr after treatment and at the end of the study. The bone loss was 10.1% less than prior to the treatment and no sites with new bone loss were found after therapy in any of the patients. The bulk of healing took place during the first year after the active therapy, while some further improvement was detected thereafter. Our results show that non-resective mechanical treatment allows excellent healing and regeneration of JP lesions. Our findings also suggest that an adequate follow-up period is needed before definite conclusions can be drawn about the efficacy of the treatment procedures used.

In vitro activity of azithromycin compared with that of erythromycin against Actinobacillus actinomycetemcomitans

The in vitro susceptibility of Actinobacillus actinomycetemcomitans to azithromycin, a new macrolide antibiotic of a new class known as azalides, was compared with that of erythromycin by the agar dilution method on Mueller-Hinton Haemophilus test medium. Eighty-two A. actinomycetemcomitans strains, 79 recent clinical isolates obtained from 40 periodontally healthy or diseased subjects, and 3 type strains were included in the study. Erythromycin showed poor in vitro activity against A. actinomycetemcomitans. Azithromycin, however, was highly effective against A. actinomycetemcomitans: all strains were inhibited at 2.0 micrograms/ml. Azithromycin exhibited the best in vitro activity against the serotype a subpopulation of A. actinomycetemcomitans: 100% of the strains were inhibited at 1.0 micrograms/ml. The lowest MICs were, however, recorded by serotype b strains. Since azithromycin has favorable pharmacokinetic properties, including excellent distribution into tissues, it could be expected to pass into gingival crevicular fluid at levels sufficient to inhibit A. actinomycetemcomitans in vivo. Therefore, it is a good candidate for future clinical trials in A. actinomycetemcomitans-associated periodontitis.

Periodontal bone loss in mice induced by different periodontopathic organisms

Periodontal bone loss in mice orally inoculated with Peptostreptococcus anaerobius, Pept. magnus and Actinobacillus actinomycetemcomitans was compared to that in sham-inoculated mice. Six-to-8-week-old BALB/c mice were inoculated with 1 x 10(5), 1 x 10(7) or 1 x 10(9) colony-forming units (c.f.u.) of bacteria in 50 microliters of medium. Ten mice received each concentration of bacteria and 10 sham-inoculated mice acted as controls. Five mice from each of the groups were killed 6 weeks after inoculation and the remaining five mice at 12 weeks. Right hemimandibles were defleshed, stained and bone loss was measured using an image analyser. All the organisms tested were associated with bone loss. Animals that had received Pept. anaerobius and Pept. magnus had up to 18% more bone loss than those sham inoculated. In contrast, mice inoculated with A. actinomycetemcomitans had up to 38% more bone loss than the sham-inoculated animals, this amount of loss occurring at the lowest inoculation of 1 x 10(5) c.f.u. These data demonstrate a differential ability of micro-organisms to cause periodontal bone loss in mice.

Clinical, laboratory, and immunological studies of a family with a high prevalence of generalized prepubertal and juvenile periodontitis

A study of a consanguineous family with a high prevalence of localized juvenile periodontitis (LJP) and generalized prepubertal periodontitis (GPP) was done over a 7-and-a-half year period. The parents had adult periodontitis, while 2 daughters, aged 13 and 15, had LJP. Furthermore, 2 other daughters, ages 14 and 10, and a son, aged 9, were affected by GPP. Two remaining siblings were not affected. Clinical and radiographic examinations on all family members were done, and chemotaxis for blood neutrophils was assessed. Laboratory tests, immunological examinations, and evaluation for neutrophil functions were done on the GPP patients. Microbiological cultures were performed on 2 of the GPP patients, as well as in the mother. The mother, the 2 LJP patients, and 1 of the unaffected siblings had depressed PMN chemotaxis. The other family members, including the 3 GPP patients, had normal PMN chemotaxis. GPP patients did not have any systemic disease, and evidence of major defects in the immunological functions was not detected. LJP patients were successfully treated with root planing, subgingival curettage, and tetracycline therapy. Intensive periodontal therapy, combined with systemic administration of antibiotics, was not effective in halting periodontal tissue destruction in the 3 GPP patients. Results indicate that the underlying cause of GPP is not always related to leukocyte dysfunction. Since Actinobacillus actinomycetemcomitans was the most frequent pathogen found in subgingival microflora of 2 of the GPP patients, it is assumed that it may play a key role in the etiology of GPP.

A follow-up case report of Actinobacillus actinomycetemcomitans in human periodontal disease

The purpose of this investigation was to compare clinical and microbial parameters in a follow-up case report of adult subjects harboring Actinobacillus actinomycetemcomitans (Aa) with clinically matched subjects who did not have detectable Aa. 16 subjects with Aa and 16 subjects without Aa at the baseline examination were re-examined at an average of 46 months following collection of baseline data. Clinical measurements were recorded and subgingival plaque sampled and evaluated for microbial flora from each maxillary first molar. In 16 subjects with Aa at baseline, 4 sites in 3 subjects had detectable actinobacilli at the follow-up appointment. 26 sites in 13 individuals with Aa at baseline had a significantly increased gingival index at the follow-up visit (p less than or equal to 0.05), but there was no significant increase in probing depth or attachment loss. 32 sites in the 16 subjects without Aa at baseline still did not have detectable levels of this microorganism at the follow-up examination nor was there any significant difference between baseline and the follow-up appointment for the gingival index, probing depth and attachment level measurements. In subjects with Aa at baseline, 1 of 12 teeth without Aa and 5 of 20 teeth with Aa had been extracted prior to the follow-up visit. In this population group, having sites where Aa was detected, 6 of 9 teeth which had a probing depth greater than or equal to 5 mm were lost before the follow-up data collection appointment. In the control group, which did not have detectable Aa at baseline, 9 teeth with probing depths greater than or equal to 5 mm were not lost. These observations, although not proving, suggest in this population group, that deeper probing depths taken together with the presence of Aa may have placed an individual at greater risk of tooth loss.

Quality assessment and meta-analysis of systemic tetracycline use in chronic adult periodontitis

The use of systemic tetracycline in the treatment of periodontal disease has been controversial. To investigate this controversy, we performed a quality assessment and attempted to perform a meta-analysis of 13 published studies. We evaluated the quality of the study protocol and data analysis and presentation for each study. We were unable to combine data from the majority of studies due to heterogeneity of the outcomes evaluated and limitations in data reported in the individual studies. Therefore, only 2 studies were included in the quantitative meta-analysis. On a scale of 0-1, the mean score for this group of studies was 0.27 (+/- 0.19) for study protocol and 0.31 (+/- 0.11) for data analysis and presentation. Mean reduction in probing depth for the group treated with tetracycline plus scaling was 2.45 mm; for the group which received only scaling, 2.02 mm; for the group that received only tetracycline, 1.98 mm; and for the control group, 0.65 mm. We conclude that analysis of data from the published literature does not demonstrate that the use of systemic tetracycline is more beneficial than conventional treatment in the management of adult periodontal disease. More information is needed in order to perform an extensive meta-analysis of this subject.

Periodontal response to mechanical non-surgical therapy: a review

This literature review is concerned with the ability of personal oral hygiene and mechanical instrumentation to establish and maintain periodontal health. Clinical, microbiologic, and histologic responses to non-surgical therapy are evaluated to provide guidelines for expected treatment results. Factors that may limit the effectiveness of non-surgical therapy as a closed procedure are also addressed. These include length of therapy, skill of therapists, patient compliance, responsibility of clinician for maintenance, and disease activity status of the patient.

A microbiological comparison of young adults based on relative amounts of subgingival calculus

This study compared the relative amounts of Actinobacillus actinomycetemcomitans (Aa), Eikenella corrodens (Ec), and black-pigmented anaerobic rods, and the proportions of coccoid forms, nonmotile rods, motile rods, spirochetes, and total motile organisms in subgingival plaque samples from 2 groups of young adults with generalized moderate to severe periodontitis. Two groups of 12 untreated patients were selected based on the relative amounts of subgingival calculus detected. Subgingival plaque samples (2 sites/patient) were taken with a sterile curet, dispersed, and plated under anaerobic conditions on ETSA, ETSA-kanamycin, ETSA-clindamycin, and TSBV agar. Appropriate biochemical tests were performed to confirm suspected microorganisms. Phase-contrast microscopy also was used to count the relative numbers of coccoid forms, nonmotile rods, motile rods, and spirochetes in each of the samples. Patients with no clinically detectable subgingival calculus harbored significantly greater proportions (%) of coccoid forms and Aa and greater amounts (CFU/mg) of Aa than did patients with obvious amounts of subgingival calculus. Subjects with clearly detectable subgingival calculus possessed greater proportions of motile rods, total motile organisms, and black-pigmented anaerobic rods than did subjects with little or no subgingival calculus. Young adult patients with generalized moderate to severe disease and little or no detectable subgingival calculus may possess a subgingival microbiota with relatively higher numbers of Aa and coccoid forms, and a lower percentage of BPB, motile rods, and total motile organisms as compared to similar patients with greater amounts of subgingival calculus.

Clinical and microbiological patterns of adults with periodontitis

Although current data suggest that periodontitis may actually be multiple diseases each with varying responses to therapy, little evidence exists to support this theory in adult patients. This report describes the design and initial findings of a longitudinal field trial involving the diagnosis and treatment of adult and refractory periodontitis patients in private practice. Adult patients (N = 221) who met specific clinical criteria were selected from the private practices of 22 periodontists. Clinical characteristics were recorded and subgingival plaque samples were sent to microbiology laboratories at either UCLA or The University of Texas Health Science Center at San Antonio (UTHSCSA). Samples were processed according to protocols standardized between the 2 centers. Five different combinations of the initial clinical and microbial findings were evaluated for patterns in the data by means of cluster analysis. Plaque, bleeding on probing, bone loss scores, probing depth distributions, and microbial findings produced multiple cluster solutions. Solutions involving 6 clusters explained 39.4% to 76.4% of the variation between patients and produced ratios for variation between clusters to variation within clusters of 5.2 to 15.3. The optimal cluster solution incorporated both clinical and microbial findings, with some clusters characterized by high plaque and moderate bleeding on probing and bone loss, whereas others had low plaque but high bleeding on probing and bone loss. Microbial findings of each cluster exhibited distinct patterns with some clusters having a high prevalence (83% to 100%) of specific target bacterial species while other clusters had an absence of these species.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of immunization with Porphyromonas gingivalis and Prevotella intermedia on progression of ligature-induced periodontitis in the nonhuman primate Macaca fascicularis

The nonhuman primate (Nhp) has proven to be a useful model of human periodontitis. This study describes the immunological characteristics of this model and the ability of active immunization to interfere with ecological changes in the microbiota and its associated disease symptoms. Nhps were parenterally immunized with whole-cell antigens of Porphyromonas gingivalis and Prevotella intermedia. The immunization elicited an approximate 2-log increase in serum immunoglobulin G (IgG), IgM, and IgA isotype antibody that was highly specific for these immunogens. Postimmunization and postligation, there was minimal change in the levels of specific antibody. P. gingivalis immunization significantly inhibited the emergence of this species during disease progression. In contrast, induction of anti-P. intermedia antibody had a minimal effect on this species within the subgingival plaque. Plaque indices showed few changes that could be attributed to active immunization. Both bleeding on probing and loss of attachment were higher in ligated sites of immunized animals than in the placebo-treated group. A significant increase in bone density loss was observed in the ligated teeth from immunized versus control animals. These findings indicate that active immunization of Nhps can elicit a substantial systemic immune response; however, while this response may effect the emergence of an individual microorganism, it appears that other ecological considerations are critical in disease progression. It is also possible that the induction of a broad-based immune response to multiple bacterial antigens can result in increased disease, potentially associated with hypersensitivity reactions to the bacteria in the subgingival plaque.

Investigation of the structure of lipid A from Actinobacillus actinomycetemcomitans strain Y4 and human clinical isolate PO 1021-7

The lipopolysaccharides of Actinobacillus actinomycetemcomitans strain Y4 and a human clinical isolate PO 1021-7 were examined by SDS/PAGE, deoxycholate/PAGE and mass spectrometry. PAGE analysis revealed an electrophoretic pattern similar to the SR-type lipopolysaccharide (LPS) of Salmonella. Deoxycholate/PAGE indicated the LPS of A. actinomycetemcomitans to consist of short sugar chains. Chemical analysis revealed the presence of thiobarbituric-acid-positive material (3-deoxy-D-manno-octulosonic acid equivalents) and four neutral sugars: glucose, galactose, D-glycero-D-manno-heptose and L-glycero-D-manno-heptose. Phosphate, glucosamine, glycine, and the fatty acids, 3-hydroxymyristic acid, myristic acid and palmitic acid, comprised the remainder of the molecule. The structure of the free lipid A revealed it to consist of a 1,6-glucosamine disaccharide esterified at C4' by a phosphomonoester. The hydroxyl group at C3 and the amide group of the non-reducing glucosamine were both acylated by 3-myristoylmyristic acid; analogous sites on the reducing glucosamine were acylated by 3-hydroxymyristic acid. Hydroxyl groups at C4 and C6' in the free lipid A were unsubstituted, with C6 being the proposed attachment site of the polysaccharide moiety. Chemical analysis revealed the presence of glycine in the intact LPS; its exact location in the A. actinomycetemcomitans LPS is still to be determined. Both intact LPS and free lipid A were highly lethal to galactosamine-sensitized mice, comparable to that of Salmonella.

Using antimicrobial agents to manage periodontal diseases

Periodontal diseases are bacterial infections and anti-microbials have been shown to be useful in their treatment and prevention. State-of-the-art treatment of refractory forms of destructive periodontal disease presently includes adjunctive use of systemic antibiotics directed to eliminating or suppressing pathogenic subgingival bacteria. Also, local application of antimicrobials by subgingival deposition or their use as irrigants during periodontal therapy are soon likely to be major components of anti-infective management of periodontal diseases. A new approach to anti-infective periodontal therapy combines ultrasonic surgical debridement with antimicrobial irrigation.

The use of genomic DNA fingerprinting in studies of the epidemiology of bacteria in periodontitis

Recent studies of microbial epidemiology emphasizing the genetic organization and distribution of organisms associated with orofacial infections have led to new insights into the possible origins of pathogenicity. Studies into genetic heterogeneity, acquisition and transmission of these organisms have been markedly advanced by the utilization of the powerful technique of genomic DNA fingerprinting. Characteristic fingerprints for each bacterial isolate can be produced by cleavage of high molecular weight genomic DNA by restriction endonucleases. It is assumed that each DNA fingerprint represents a clonal type. In this report, we review and analyze studies of the epidemiology of bacteria associated with orofacial infections with an emphasis on periodontal disease. Studies of nontypable (NT) Haemophilus influenzae associated with recurrent otitis media illustrate the utility of this technique. DNA fingerprinting clearly demonstrates genetic heterogeneity of NT H. influenzae isolates, and clonality of infection of any individual. Furthermore, DNA fingerprinting has shown that the same clonal type is seen in siblings concurrently suffering from otitis media, suggesting horizontal transmission within the family. Studies of mutans Streptococci also show extensive genetic heterogeneity and show vertical transmission of a predominant clonal type only from mother to infant, but not from father to infant. Studies of Actinobacillus actinomycetemcomitans show considerable genetic heterogeneity among monkey isolates. Thus far, three clonal types have been reported with DNA fingerprinting among isolates from periodontal patients, but additional genetic heterogeneity can be found using specific DNA fragments as probes in hybridization experiments. Intrafamilial transmission of A. actinomycetemcomitans has been demonstrated. Porphyromonas (Bacteroides) gingivalis shows extensive genetic heterogeneity and case reports suggest clonal infection of any one individual. In contrast, results with DNA fingerprinting of Eikenella corrodens, Fusobacterium nucleatum, and Bacteroides intermedius show that individuals may be infected with 2 or more clonal types. These studies point to the great potential of DNA fingerprinting for investigating the epidemiology of putative orofacial pathogens. Such studies with periodontal microorganisms will likely reveal steps in the acquisition, intraoral and person-to-person transmission, which then could possibly be inhibited or interfered with to prevent periodontal disease or its recurrence.

Black-pigmenting gram-negative bacteria in periodontal disease. II. Screening strategies for detection of P. gingivalis

The purpose of this analysis was to evaluate the feasibility of detecting P. gingivalis using selected sites and to indicate increased proportions of this organism in periodontitis patients. In 10 patients suffering from moderate to advanced periodontal disease, separate microbiological samples were taken from the mesial, buccal, distal and oral (lingual or palatal) aspects of every tooth. This yielded a total of 927 microbiological samples, 84 to 102 per patient. Three distinct patterns of distribution and relative proportion of P. gingivalis were recognized. In one group of patients, the organism was not cultured. In a second group, few positive sites with low proportions of P. gingivalis were present. A third group of patients yielded high frequencies and proportions of P. gingivalis. The number of samples necessary to diagnose the presence of P. gingivalis at a 95% confidence level varied considerably between the three groups. In 4 patients, sampling 4 randomly selected sites was sufficient, while in the remaining 3 positive patients, 25 or more samples were required to detect the organism with equal certainty. Seven different protocols for multiple subgingival sampling were studied. When considering the number of samples needed to detect the presence of P. gingivalis and to estimate the highest proportion of this organism, selection of the deepest pocket in each quadrant was the most efficient method of sampling.

Microbiology in the management of destructive periodontal disease

This paper summarizes the rationale for the application of microbiology in the management of destructive periodontal diseases. The subgingival microbiota in patients with severe periodontitis is complex and contains high numbers of obligate anaerobic bacteria as well as facultative micro-organisms. It has become clear that major differences exist in the composition of the subgingival microflora. These differences are not only quantitative but also qualitative. Difference in plaque composition is the basis for the application of clinical microbiology in the management of periodontal disease. Several bacterial species have emerged as useful indicators for progressive periodontitis. In this respect, the importance of Actinobacillus actinomycetemcomitans, Bacteroides gingivalis and Bacteroides intermedius has been shown in a number of studies. It has become clear that A. actinomycetemcomitans is not specifically associated with the local form of juvenile periodontitis, but this micro-organism is probably also of importance in severe periodontitis in adult patients. Selection of individuals with an A. actinomycetemcomitans associated periodontitis is essential since successful treatment in these patients needs an adjunctive antibiotic therapy. Microbiological testing can be useful in patients showing a poor response to periodontal treatment (refractory periodontitis). Factors which may be responsible include poor oral hygiene, poor subgingival debridement, the patient's susceptibility and a subgingival microflora resistant to therapy. In this patient category, microbiological testing is capable of diverting continuing periodontal treatment. Furthermore, microbiology can be useful in evaluating periodontal treatment. Successful elimination of specific periodontopathic microorganisms can be used to determine recall intervals.

Dental bacterial plaques. Nature and role in periodontal disease

Antony van Leeuwenhoek first described oral bacteria. However, not until almost 200 years later was the famous Koch postulate introduced. Since then, research has extensively been performed regarding the development and microbiology of dental plaques. In spite of the complexity of the developing flora of supragingival plaque, culture studies have shown a remarkably orderly succession of organisms. Lately, the concept of microbial specificity in the etiology of periodontal diseases has been widely suggested, i.e., that different forms of periodontal disease are associated with qualitatively distinct dental plaques. Cross-sectional and longitudinal studies of the predominant cultivable microflora reveal that only a small number of the over 300 species found in human subgingival plaques are associated with periodontal disease. Among the commonly mentioned are: Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, Bacteroides intermedius, Capnocytophaga sp., Eikenella corrodens, Fusobacterium nucleatum, and Wolinella recta, as well as certain gram-positive bacteria such as Eubacterium species. Anti-infective therapy for many systemic infections equals the use of antimicrobial drugs. However, for localized infections like periodontal diseases, treatment may consist of a combination of mechanical wound debridement and the application of an antimicrobial agent. The general effectiveness of mechanical anti-infective therapy and successful oral hygiene in the management of periodontal disease is well established in the literature and has met the test of success in clinical practice for most cases of periodontitis in adults. The definition of periodontal pathogens as either opportunistic pathogens, or as exogenous pathogens carries with it significant implications.(ABSTRACT TRUNCATED AT 250 WORDS)

Tetracyclines inhibit connective tissue breakdown: new therapeutic implications for an old family of drugs

Tetracyclines have long been considered useful adjuncts in peridontal therapy based on their antimicrobial efficacy against putative periodontopathogens. However, recently these drugs were found to inhibit mammalian collagenases and several other matrix metalloproteinases (MMPs) by a mechanism independent of their antimicrobial activity. Evidence is presented that this property may be therapeutically useful in retarding pathologic connective tissue breakdown, including bone resorption. The experiments leading to this discovery are described and possible mechanisms are addressed, including the specificity of tetracyclines' anti-collagenase activity, the role of the drugs' metal ion (Zn2+, Ca2+)-binding capacity, and the site on the tetracycline molecule responsible for this nonantimicrobial property. Of extreme interest, the tetracycline molecule has been chemically modified in multiple ways, generating a new family of compounds called CMTs (chemically modified tetracyclines) that lack antimicrobial but still retain anti-collagenase activity. The first of these CMTs, 4-de-di-methylaminotetracycline, was found not to produce a major side-effect of antimicrobial tetracycline therapy--its administration to experimental animals did not result in the emergence of tetracycline-resistant microorganisms in the oral flora and gut. Numerous examples of the clinical potential of this non-antimicrobial property of tetracyclines in the treatment of periodontal and several medical diseases (e.g., sterile corneal ulcers, rheumatoid arthritis, skin bullous lesions, tumor-induced angiogenesis and metastasis) are discussed.

Synergistic effects between amoxicillin, metronidazole, and the hydroxymetabolite of metronidazole against Actinobacillus actinomycetemcomitans

Interactions between metronidazole and amoxicillin, metronidazole and its hydroxymetabolite, and amoxicillin and the hydroxymetabolite of metronidazole were investigated with checkerboard titrations in combination with accurately determined MICs and MBCs. Actinobacillus actinomycetemcomitans was used as the test organism. Synergism was found for all three combinations. Fractional inhibitory concentration indices and fractional bactericidal concentration indices varied from 0.3 to 0.7. These synergistic interactions between these antibiotics may explain the efficacy of the combination of metronidazole and amoxicillin in various bacterial infections, including periodontal disease.

Periodontal disease in HIV-infected patients in relation to lymphocyte subsets and specific micro-organisms

Visible plaque index (VPI), gingival bleeding index (GBI) and pocket depth (PD) were analyzed in relation to potential periodontal pathogenic microorganisms and peripheral numbers of T4+ and T8+ lymphocyte subsets in 10 patients with human immunodeficiency virus (HIV) infection, 10 patients with AIDS related complex (ARC) and 10 patients with acquired immune deficiency syndrome (AIDS). 10 healthy persons served as controls. Periodontal disease in patients with more advanced stages of HIV infection were related to the severity of the systemic disease, and to decreasing numbers of T4+ lymphocytes in peripheral blood, but not to VPI or the occurrence of periodontal pathogenic micro-organisms.

Factors in virulence expression and their role in periodontal disease pathogenesis

The classic progression of the development of periodontitis with its associated formation of an inflammatory lesion is characterized by a highly reproducible microbiological progression of a Gram-positive microbiota to a highly pathogenic Gram-negative one. While this Gram-negative microbiota is estimated to consist of at least 300 different microbial species, it appears to consist of a very limited number of microbial species that are involved in the destruction of periodontal diseases. Among these "putative periodontopathic species" are members of the genera Porphyromonas, Bacteroides, Fusobacterium, Wolinella, Actinobacillus, Capnocytophaga, and Eikenella. While members of the genera Actinomyces and Streptococcus may not be directly involved in the microbial progression, these species do appear to be essential to the construction of the network of microbial species that comprise both the subgingival plaque matrix. The temporal fluctuation (emergence/disappearance) of members of this microbiota from the developing lesion appears to depend upon the physical interaction of the periodontal pocket inhabitants, as well as the utilization of the metabolic end-products of the respective species intimately involved in the disease progression. A concerted action of the end-products of prokaryotic metabolism and the destruction of host tissues through the action of a large number of excreted proteolytic enzymes from several of these periodontopathogens contribute directly to the periodontal disease process.(ABSTRACT TRUNCATED AT 250 WORDS)

Occurrence of doxycycline resistant bacteria in the oral cavity after local administration of doxycycline in patients with periodontal disease

Topical antimicrobial treatment is appearing as a means of therapy in patients with advanced periodontal disease. The purpose of the present study was to examine the occurrence of doxycycline resistant bacteria in subgingival plaque and oral cavity after local administration of doxycycline. Five patients with advanced marginal periodontitis were scaled, and one approximal pocket in each patient was additionally treated with locally delivered doxycycline. Microbiological samples were obtained from the test site, a contralateral control site and tongue and tonsils before treatment and 3, 13, 26 and 52 weeks after treatment. The occurrence and morphological distribution of doxycycline resistant bacteria was determined after anaerobic cultivation on enriched tryptic soy agar with and without doxycycline incorporated. At the test site and on tongue and tonsils the percentage of doxycycline resistant bacteria increased from less than 1% before treatment to 22% and 35%, respectively, immediately after treatment, but decreased again at week 13. At the control site no increase was observed. Gram-positive cocci constituted the majority of doxycycline resistant bacteria at all 3 sampling sites (73-94%). The morphological distribution of resistant bacteria was not affected by the doxycycline therapy. Thus, local doxycycline therapy resulted only in a transient increase in resistance in the oral microflora.

Microbiological study of HIV-related periodontitis

The subgingival microbiota in 14 persons with HIV-periodontitis was examined. Subgingival plaque samples were collected with paper points, transported in VMGA III, and plated on anaerobic enriched brucella blood agar and various selective media. HIV-periodontitis sites revealed Actinobacillus actinomycetemcomitans, Wolinella recta, Peptostreptococcus micros, and Bacteroides intermedius, each averaging 7% to 16% of the cultivable subgingival flora in positive patients. High levels of spirochetes also were detected in diseased sites with phase-contrast microscopy. Low levels of Candida albicans or enteric Gram-negative rods were recovered in the subgingival flora in 7 HIV-periodontitis patients or Bacteroides fragilis, Fusobacterium necrophorum, Fusobacterium varium, and Eubacterium aerofaciens were recovered in 8 patients. These findings suggest that the major components of the subgingival microbial flora in HIV-periodontitis are similar to those associated with adult periodontitis in systemically healthy persons. However, HIV-periodontitis lesions also may contain organisms which are rarely found in common types of periodontitis. The etiological significance of specific periodontal organisms in HIV-periodontitis awaits further longitudinal study.

Repair potential in localized juvenile periodontitis. A case in point

An aggressive form of localized juvenile periodontitis (LJP) in a 12-year old West African female is reported. The case was treated with scaling, root planing, debridement, and tetracycline therapy, which resulted in complete resolution of the disease, including elimination of periodontal inflammation, regeneration of lost periodontal structures, and spontaneous repositioning of teeth that had pathologically migrated. A hopelessly involved mandibular right first molar was successfully replaced by an incompletely developed maxillary third molar tooth bud whose roots and pulp structure continued to develop after autotransplantation. It is suggested, that LJP can be successfully treated without periodontal surgery and that the potential for repair in LJP cases is apparently greater than what one can anticipate in adult forms of periodontitis.

Reviewing nonsurgical periodontal therapy

Selection of the appropriate case and clinical competency in treatment modalities results in success in nonsurgical periodontal therapy. The patient with early periodontitis with significant local factors in the form of professionally accessible plaque and calculus is the most receptive to nonsurgical periodontal treatment. The clinician must make decisions centering around the important question, "Can the patient, or moreover, can the therapist delivering the debridement, gain access to the microbial subgingival plaque on a frequent basis below the host defense threshold of the respective patient?" If the answer is "yes," nonsurgical periodontal therapy will be rewarding. If the answer is "no," other modalities such as periodontal surgery must be instituted.

Identification of polymorphonuclear leukocyte collagenase and gelatinase activities in mouthrinse samples: correlation with periodontal disease activity in adult and juvenile periodontitis

In previous studies, elevations in the levels of active and latent collagenase in gingival crevicular fluid (GCF) have been correlated positively with periodontal disease activity. To provide a simple diagnostic approach for testing collagenolytic activity, the feasibility of using a 3.0 ml water mouthrinse to collect GCF simultaneously from all sites in the mouth was assessed. Patients with adult periodontitis (AP, n = 23) and local juvenile periodontitis (LJP, n = 7) were sampled before periodontal therapy and some (12 AP, 4 LJP) were also assessed longitudinally after scaling and root planing, administration of antibiotics, and following periodontal surgery. Healthy patients (n = 19) were used as controls. The levels of active collagenase, procollagenase, and collagenase inhibitor activity were determined by functional assays and quantitated after SDS-PAGE and fluorography. Gelatinase and progelatinase were assayed by enzymography on gelatin-substrate gels. Active collagenase levels were found to be significantly higher (14- to 20-fold) in AP and LJP patients compared to controls, whereas matrix metalloproteinase activity was not detected in mouthrinses from edentulous patients. Collagenase inhibitor levels were generally low in all groups of subjects tested. Following clinical treatment the levels of active collagenase and gelatinase were reduced; the reduction was significant for active collagenase after tetracycline treatment and scaling in LJP patients. Of the clinical indices recorded (gingival index, plaque index, and pocket depth) there were no significant correlations with enzyme activity but similar trends were observed between the changes in active collagenase and gingival index. In patients with untreated periodontal disease, collagenase occurred predominantly in the active form. N-ethylmaleimide (NEM) and p-aminophenylmercuric acetate (AMPA) were equally effective as activators of the latent collagenase, indicating that the collagenase was derived from PMNs, which were also the source of gelatinase. The results of these studies indicate that measurement of active collagenase and gelatinase in mouthrinse samples is potentially useful in the diagnosis and assessment of periodontal disease activity.

Generalized juvenile periodontitis: report of a familial case followed for 5 years

The case of a family, followed for 5 years and showing an exceptionally high prevalence of Generalized Juvenile Periodontitis (GJP), is presented. Two siblings were affected by a severe form of GJP meanwhile the dycorial twin of one was periodontally healthy. Both the affected siblings showed infection by Actinobacillus actinomycetemcomitans (Aa), but only one presented a reduced chemotaxis of the peripheral PMNs. The dycorial twin consistently displayed a freedom from Aa and a reduction in the peripheral PMNs chemotaxis. The extraction of the compromised teeth in the two affected siblings has been followed by colonization of new sites by Aa; only repeated administration of systemic tetracyclines seems to protect the subjects from colonization of other sites. These findings may contribute to the understanding of the etiology, pathogenesis, and therapy of juvenile periodontitis.

Doxycycline-resistant bacteria in periodontally diseased individuals after systemic doxycycline therapy and in healthy individuals

The occurrence of doxycycline-resistant bacteria was examined in subgingival plaque and on the tonsils of 12 periodontally healthy and 12 periodontally diseased individuals. The healthy group was examined 6 times at intervals of one month. The diseased group was examined before and 1, 5, 15, 26, 39, and 52 weeks after conventional periodontal therapy supplemented with systemic doxycycline for 3 weeks. The occurrence of doxycycline-resistant bacteria in the healthy group varied on average between 2.0% and 6.6% in subgingival plaque and between 3.0% and 12.4% in the tonsil samples over a 6-month period. In the diseased group the percentage of resistant bacteria increased from 10-20 times for tonsil and subgingival plaque, respectively. About half a year after therapy the values returned to the baselines. For both groups the morphological distributions of resistant bacteria were similar and unaffected by the doxycycline therapy.

Antibiotics in periodontal therapy: advantages and disadvantages

Antibiotic treatment of periodontitis aims at eradicating or controlling specific pathogens. Prime candidates for antibiotic therapy are patients with recently diagnosed active periodontitis or a history of recurrent disease who fail to stabilize following mechanical/surgical therapy. Since a variety of microbes with differing antimicrobial susceptibility profiles may cause periodontitis, selection of antimicrobial agents should be based on proper microbial diagnosis and sensitivity testing, as well as consideration of the patient's medical status. The risk of treating chemotherapeutically solely on the basis of clinical features, radiographic findings or a limited microbiological analysis, is failure to control the pathogens or overgrowth of new pathogens. A review of published papers reveals that appropriate systemic antibiotic therapy may enhance healing in patients with recent or high risk of periodontal breakdown. Systemic antibiotic therapy seems more predictable than topical administration in eradicating periodontal pathogens from deep periodontal pockets. Several promising antimicrobial agents for periodontitis treatment need testing in placebo-controlled, double-blind, randomized clinical trials.

Implants and infections with special reference to oral bacteria

Osseointegration or bony anchorage of oral implants was first described by Brånemark and coworkers. This type of connection between the titanium oxide layer and the bone gives stable long-term results for the implants in function. Fibrous tissue interphase between implant and bone will allow mobility which will gradually increase and cause implant failure. The microbiota around stable versus failing implants seem to parallel the patterns around healthy versus diseased natural teeth. Infections most often develop around failing implants. This may create mostly localized, but sometimes even widespread serious infection problems. Metastatic infectious problems related to endo-prosthesis replacing joints and cardiovascular structures are briefly discussed in connection with bacteremia caused by oral infections in general and surgical procedures.

Split-mouth and cross-over designs in dental research

The presence of paired or multiple organs (arches, quadrants, teeth) and the chronic nature of many dental diseases suggest the use of split-mouth (trials in which each subject receives greater than or equal to 2 treatments, each to a separate section of the mouth) and cross-over research designs (trials in which each subject receives greater than or equal to 2 treatments in sequence). While these designs offer potential savings in resources, their usefulness can be negated if several strict scientific and statistical assumptions are not met. The primary prerequisites for the use of split-mouth and cross-over designs are that: (1) the disease to be investigated is relatively stable and uniformly distributed; (2) the effects of the treatments to be evaluated are short-lived or reversible for cross-over studies, or are localized for split-mouth designs. Other important factors that influence the appropriate use of these designs include: the method of treatment sequencing and assignment, and the cross-over rules used; blinding of patient assignment, patients and observers; assessment of order effects including period, carry-over or spill-over effects; the choice of statistical analysis, the sample size utilized, and the special importance of patients lost to study or of faulty data points. The objective of this study was to review 3 journals for studies using split-mouth or cross-over designs to determine how the assumptions underlying these research designs are considered and applied in dental research. The majority of studies used adequate methods for treatment allocation and sequencing; however, many studies failed to take advantage of the research designs in the statistical analysis of data. In addition, very few studies considered the possibility of order effects or reduced bias through blinding procedures.

Effect of root debridement on the elimination of Actinobacillus actinomycetemcomitans and Bacteroides gingivalis from periodontal pockets

The aims of this 6-month longitudinal study were: (1) to investigate to what extent root debridement of pockets in adult periodontitis will reduce the subgingival presence of Actinobacillus actinomycetemcomitans, Bacteroides gingivalis and some other bacterial groups; (2) to relate the microbiological results following debridement to clinical measurements of healing. 16 patients and a total of 111 periodontally involved sites with probing depth greater than or equal to 6 mm served for the study. Duplicate subgingival microbial samples and duplicate clinical recordings were obtained 1 week apart at baseline and at 6 months following supra- and subgingival debridement. The results demonstrated reductions of the mean total viable counts and reductions of the mean counts of several of the cultured groups of micro-organisms coupled with significant improvements of mean clinical measurements. B. gingivalis was eliminated from a majority of infected subgingival sites. A. actinomycetemcomitans, on the other hand, still remained after therapy in a high proportion of sites initially infected with this microorganism. Subgingival persistence of A. actinomycetemcomitans appeared to be associated with a reduced healing response following debridement. Further studies are needed to clarify why A. actinomycetemcomitans is poorly eliminated following debridement. Also, the long-term clinical significance of the subgingival perseverance of A. actinomycetemcomitans needs to be elucidated.

On the inability of root debridement and periodontal surgery to eliminate Actinobacillus actinomycetemcomitans from periodontal pockets

In a previous study, we observed that root debridement was inefficient in eliminating Actinobacillus actinomycetemcomitans from adult periodontitis lesions. The present report describes the effects on A. actinomycetemcomitans of subsequent treatments of 6 patients that had at least 2 separate sites still harboring A. actinomycetemcomitans 6 months following debridement. 1 site or more in each individual was treated with renewed root debridement and at least 1 other site was treated by surgical excision of the gingival tissue. The results indicated that retreatment with either repeated root debridement or with surgical excision of the gingival tissue was not more effective in eliminating A. actinomycetemcomitans than initial debridement. The possible reasons for this limited therapeutic effect on the subgingival presence of A. actinomycetemcomitans are discussed.

Rationale for the use of antimicrobial agents in periodontal disease

The traditional approach to treating dental decay and periodontal disease has often focused on caries, neglecting periodontal infection. The past 15 years have seen significant advances in the treatment of periodontal disease with antimicrobial therapy, both with and without more traditional debridement or surgery. This article presents an overview of the use of antimicrobials, including an examination of treatment philosophies and the diagnosis of periodontal infection.