Subgingival microflora and periodontal disease

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.

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)

Identification of components in Fusobacterium nucleatum chemostat-culture supernatants that are potent inhibitors of human gingival fibroblast proliferation

The present investigation concerned the effect of chemostat-culture cell-free supernatants of Fusobacterium nucleatum on the growth and synthetic activity of human gingival fibroblasts in vitro. Human gingival fibroblasts were cultured in fetal calf serum supplemented Dulbecco-Vogt medium containing various dilutions of conditioned or unconditioned bacterial culture medium. Cell proliferation was monitored by assessing cell growth over 5 days or incorporation of [3H]-thymidine into DNA. Protein and proteoglycan synthesis were monitored by the incorporation of [3H]-proline and [35S]-sulfate, respectively, into macromolecules. While the conditioned culture medium caused a complete inhibition of cell growth and incorporation of [3H]-thymidine DNA, there was no discernible effect on protein or proteoglycan synthesis. This indicated that the cells remained viable yet unable to divide. Such a view was supported by the observation that the inhibitory effect was reversible upon removal of the conditioned medium. This activity had a molecular size less than 30,000, was heat-stable and nonvolatile. Chemical analysis of the conditioned bacterial culture supernatants indicated that high proportions of butyrate, ammonium, and acetate were present. When these components were added to unconditioned medium and tested, most of the inhibitory activity could be attributed to ammonium and butyrate. Since many bacteria which constitute the subgingival microflora release ammonium and butyrate, a very high concentration of these metabolites may well accumulate. Clearly, the potential for inhibition of fibroblast proliferation has ramifications related to diminished tissue repair following bacterially-induced periodontal destruction.

Immune modulation of Prevotella intermedia colonization in squirrel monkeys

Colonization of the gingival crevice by black-pigmented Porphyromonas or Prevotella spp. (BP/P), including Porphyromonas gingivalis (formerly Bacteroides gingivalis) and Prevotella intermedia (formerly Bacteroides intermedius), is thought to be an important ecological event which may result in the destruction of connective tissues supporting the teeth. Theoretically, periodontal diseases could be prevented if these or other periodontal pathogenic microorganisms did not colonize the subgingival area. The humoral immune response is one mechanism which may modulate bacterial colonization in the gingival crevice. In the present study, we tested the effect of systemic humoral immunity on subgingival colonization by indigenous P. intermedia in squirrel monkeys (Saimiri sciureus). Animals rendered essentially free of detectable BP/P by a single scaling, 10 days of tetracycline therapy, and toothbrushing three times per week were immunized with P. intermedia 1447 or were sham immunized with phosphate-buffered saline. Subsequently, all oral hygiene procedures were discontinued and five teeth in one quadrant were ligated with bacterium-soaked suture material to facilitate BP/P colonization. Immunization resulted in a significant increase in the level of immunoglobulin G anti-P. intermedia antibody in serum. Two weeks after ligation was initiated, P. intermedia could be detected in five of six sham-immunized and three of six immunized animals. Immunization was associated with a reduction in the emergence of indigenous P. intermedia in the gingival crevice.

Enhanced repair and regeneration of periodontal lesions in tetracycline-treated patients. Case reports

A group of cases is presented in which dramatic repair and regeneration of periodontal tissues lost as a result of periodontitis have occurred following systemic administration of tetracycline either alone or in combination with other forms of periodontal therapy. The nature and extent of regeneration demonstrated in these patients appears to be more dramatic than what has been shown previously when more conventional forms of periodontal therapy were utilized, even including bone grafting and guided tissue regeneration. The type of repair described has been shown in many instances to be long standing and is probably not totally related to the antibacterial characteristics of tetracycline. It is suggested that the ability of this drug to inhibit collagenolytic enzymes (collagenases) may have influenced the favorable clinical results achieved. The anti-collagenolytic properties of tetracycline are being considered with increasing frequency in the treatment of other systemic diseases characterized by collagen breakdown such as corneal ulcers, rheumatoid arthritis, diabetes, and dystrophic epidermolysis bullosa. Given the highly collagenous nature of the tissues of the periodontium, this report suggests that tetracycline could be of considerable value in the treatment of some types of periodontitis.

Serum antibody in Actinobacillus actinomycetemcomitans-infected patients with periodontal disease

This study was designed to (i) delineate the characteristics of serum antibody responses to Actinobacillus actinomycetemcomitans in patients with periodontitis who are infected with A. actinomycetemcomitans; irrespective of disease classification; (ii) assess the relationship of the elevated antibody levels to colonization of the oral cavity by A. actinomycetemcomitans; and (iii) describe the serotype distribution of A. actinomycetemcomitans and antibodies to the microorganism in infected patients with various clinical classifications. To compare the levels of various isotype-specific antibodies to the different antigens, studies were performed that allowed quantitation of each isotype-specific antibody in a human reference standard. By using this reference standard, it was shown that the levels of immunoglobulin G (IgG), IgM, and IgA responses to A. actinomycetemcomitans were similar among the infected patients, irrespective of disease classification. Also, we demonstrated that the serum antibody response to serotype b was quantitatively greater in all isotypes. Our findings indicate that b was the most frequent A. actinomycetemcomitans serotype detected in the patients and appears to be capable of initiating a substantial serum IgG antibody response that may contain cross-reactive antibodies to other serotypes of A. actinomycetemcomitans. Generally, in cases in which the response to a single serotype was elevated, only that type of A. actinomycetemcomitans was detected in the plaque. Individuals exhibiting elevated antibodies to multiple serotypes were most consistently colonized by the serotype b microorganism. This study represents the first report detailing the distribution of IgG subclass antibodies to A. actinomycetemcomitans in periodontal disease. The results demonstrated that the primary responses of patients with periodontitis to A. actinomycetemcomitans were of the IgG1 and IgG3 subclasses, which is consistent with elicited responses to protein antigens. In contrast, the primary subclass response in normal subjects was limited to the IgG2 subclass and may represent broader cross-reactivity to polysaccharide antigens-lipopolysaccharide from the bacteria.

Single-dose concentrations of tinidazole in gingival crevicular fluid, serum, and gingival tissue in adults with periodontitis

Previous studies have shown that metronidazole is effective in the treatment of subgingival microflora associated with destructive periodontitis. The aim of this study was to determine whether tinidazole, a close analogue of metronidazole, would reach sufficient concentrations in serum, gingival crevicular fluid, and gingival tissue, to inhibit putative periodontopathic bacteria. Ten adult patients with moderate to advanced periodontitis took a single 2-g dose of tinidazole orally. Samples were assayed by high-performance liquid chromatography. The concentrations of tinidazole in serum and GCF were in a similar range (3.2-46.5 micrograms/mL). Tinidazole was not detected in the GCF in three of the patients. The drug was found in gingival tissue obtained at two h (0.17 +/- 0.14 micrograms/mg) and six h (0.15 +/- 0.18 micrograms/mg) after oral administration. The mean concentration of tinidazole in serum at 24 h (13 +/- 3.0 micrograms/mL) is greater than the minimum inhibitory concentration for anaerobic bacteria as reported by others. The present data suggest that a single 2-g oral dose of tinidazole may lead to the presence of potentially bactericidal levels of tinidazole for up to 24 h in the periodontal pockets of some patients with periodontitis.

Comparison of the antimicrobial effect of the application of chlorhexidine gel, amine fluoride gel and stannous fluoride gel in debrided periodontal pockets

The clinical and microbiological effect of locally-applied chlorhexidine gel 2%, amine fluoride gel 1.25%, stannous fluoride gel 4% or placebo gel in 40 periodontal pockets of 10 patients were studied. The gels were applied 3 x within 10 min. after mechanical debridement of the pockets. The treatment effect on the subgingival microflora was evaluated by microscopic and culture studies of the subgingival plaque samples. In addition, supragingival plaque, bleeding after probing and probing pocket depth were scored. Examination were carried out before and during a period of 36 weeks after treatment. At the start, the cultured microflora consisted mainly of anaerobic Gram-positive bacteria. Following treatment, the clinical parameters were significantly reduced. Concomitantly, the %s of spirochetes, motile rods and non-motile rods decreased significantly. A significant decrease was also found in the total anaerobic count, whereas the facultative counts remained at the same level found before treatment. This suggested that the treatment resulted in a mainly facultative subgingival microflora. The % Gram-negative rods showed a significant reduction after treatment, but returned to base line at week 12. Statistical analysis of the bacteriological and clinical examinations failed to demonstrate any significant differences between the 4 treatment groups. Thus, in comparison to the placebo gel, subgingival application of chlorhexidine gel 2%, amine fluoride gel 1.25% or stannous fluoride gel 4% did not augment the effect of mechanical debridement on bacteriological and clinical parameters during the experimental period of 36 weeks. However the indicated treatments resulted in a facultative subgingival microflora which is compatible with the host.

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)

Identification, and susceptibility to seven antimicrobial agents, of 61 gram-negative anaerobic rods from periodontal pockets

Sixty-one cultures of Gram-negative anaerobic rods were isolated from deep periodontal pockets of patients with rapidly progressive periodontitis. Isolates were speciated as Bacteroides gingivalis (18 isolates), Bacteroides intermedius (8), Bacteroides oris (1), Bacteroides gracilis (17) and Fusobacterium nucleatum (17). Their susceptibilities, to seven antimicrobial agents, were determined in vitro using a plate dilution technique. Amoxycillin and amoxycillin with clavulanic acid were active against all isolates (MIC less than 1 mg/l) and proved the most effective agents tested. F. nucleatum and B. gracilis showed resistance to erythromycin; F. nucleatum had MIC values ranging from 0.03 mg/l up to 128 mg/l when tested with this, least effective agent. Metronidazole was effective against all isolates except for a few strains of B. gracilis (MIC less than 4 mg/l). Tetracycline hydrochloride and minocycline were active against all isolates except for a few strains of B. gracilis (MIC less than 2 mg/l with both minocycline and tetracycline hydrochloride). Penicillin proved less effective than amoxycillin with regard to inhibition of B. gracilis.

DNA probe detection of periodontal pathogens in HIV-associated periodontal lesions

Recent studies have shown that an atypical gingivitis and a rapidly progressive periodontal disease may be early-occurring opportunistic infections associated with human immunodeficiency virus (HIV) infection. This study examined the prevalence of selected periodontal pathogens associated with these HIV-related periodontal lesions. Subgingival plaque samples were obtained from both HIV-seronegative and HIV-seropositive homosexual men and from presumably uninfected heterosexual men. DNA probes were used to detect Actinobacillus actinomycetemcomitans, Bacteroides intermedius, Bacteroides gingivalis, Eikenella corrodens and Wolinella recta in the plaque. The healthy sites in both the seronegative and seropositive homosexual groups showed a greater prevalence of all test bacteria, except for E. corrodens, than did the heterosexual group. HIV-associated periodontitis sites showed a microbial profile qualitatively similar to that of conventional periodontitis, except that B. gingivalis was more prevalent in conventional periodontitis. In contrast, HIV-associated gingivitis sites exhibited a greater prevalence of all bacteria tested than conventional gingivitis sites. In fact, HIV gingivitis generally showed a bacterial profile similar to that of the HIV periodontitis lesions, except that W. recta was significantly more prevalent in HIV periodontitis. These data suggest that the HIV gingivitis lesion is a precursor to HIV periodontitis. Thus, early identification and prophylactic treatment of high-risk individuals may prevent the destruction of periodontal tissues.

Biochemical comparison of proteolytic enzymes present in rough- and smooth-surfaced capnocytophagas isolated from the subgingival plaque of periodontitis patients

Four rough-surfaced (R) and three smooth-surfaced (S) clinical isolates of Capnocytophaga obtained from the subgingival plaque of periodontitis patients were studied for their peptidase and protease profiles. The results were compared with those obtained with C. gingivalis (which has a smooth morphology). All cell extracts obtained by ultrasonic treatment displayed high peptidase activity toward N-aminoacyl-2-naphthylamines, the best substrates being the arginyl, aspartyl, and leucyl derivatives. The R and S isolates did not differ in these enzyme activities. Also the protease profiles studies with 4-phenylazobenzyloxycarbonyl-L-prolyl-L-leucylglycyl-L-proly l-D-arginine (PZ-PLPGA) and casein were similar. All extracts also hydrolyzed furylacryloyl-L-leucylglycyl-L-prolyl-L-alanine (FALGPA), reconstituted type I [3H]-collagen, and gelatin. N alpha-Benzoyl-DL-rginyl-2-naphthylamine was hydrolyzed faster by the R than the S strains. Comparison between cell suspensions and cell extracts of C. gingivalis showed the suspensions to be enzymatically more active than the extracts. In general, peptidase substrates and PZ-PLGPA were hydrolyzed at a higher rate by suspensions than by extracts, while protease substrates (such as casein) were hydrolyzed faster by the extracts. Gelatin and FALGPA were hydrolyzed by cell extracts only. Fast protein liquid chromatography of peptidases on a gel column was found to be a suitable method to differentiate between R and S isolates in diagnostics, while the chromatographic profiles of proteases were not suitable for this purpose.

Topical chemotherapy in human periodontitis using a new controlled-release insert containing ofloxacin. I. Microbiological observation

The recognition that destructive periodontal diseases may be caused by specific microorganisms in periodontal pockets has led to an increased interest in and usage of antimicrobial agents in periodontal therapy. Recently, a new controlled-release insert containing ofloxacin, a synthetic antibiotic, has been developed. In this study, the controlled-release insert (PT-01) was microbiologically evaluated in combination with or without subgingival mechanical debridement. PT-01 was applied in the periodontal pockets of 27 patients with chronic periodontitis. Three sites with a deep probing pocket depth (greater than or equal to 5 mm) were randomly selected in different quadrants of each patient, and were assigned into three groups, i.e., PT-01 applied (T), placebo applied (P) and control sites (C). Periodontal treatments consisted of supragingival scaling with oral hygiene instruction for the first 2 weeks followed by root planing and subgingival scaling PT-01 was applied weekly on day 0 to 35, and the subgingival plaque samples from each site were collected on d 0, 14, 21 and 42. The dynamics of the subgingival microflora was investigated by dark field microscopy and by anaerobic and aerobic cultivation. In the supragingival scaling period, significant reduction in percentages of spirochetes and motile rods and significant increase of the percentage of coccoid cells were observed only at T sites. In addition, the total viable counts of bacteria, black-pigmented Bacteroides and Fusobacterium species were significantly reduced at T sites. After mechanical subgingival debridement, significant shifts in the proportion and reduction of the viable counts in the subgingival microflora were found at all sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Microbiological and immunological aspects of experimental periodontal disease in rats: a review article

Animal models in which microbiological and immunological aspects of periodontal disease can be studied prospectively seem well warranted. The rat bears much resemblance to man with respect to periodontal anatomy, development and composition of dental plaque, histopathology of periodontal lesions, and basic immunobiology. Furthermore, reproducible methods are available for assessment of periodontal disease in rats, and detectable periodontal destruction can be induced in a few weeks in these animals without traumatizing periodontal tissues with ligatures. Experimental periodontitis studies in germ-free rats have confirmed the pathogenicity of several suspected periodontal pathogens (Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Capnocytophaga sputigena, Eikenella corrodens, and Fusobacterium nucleatum). The studies also suggest that the number of periodontal pathogens may be higher than generally believed, since species like Streptococcus sobrinus and Actinomyces viscosus are associated with periodontal bone loss in rats. Studies in rats with congenital or induced immune defects indicate that generalized or selective immunosuppression at the time of infection with periodontal pathogens may aggravate periodontal disease. Studies in immunized rats indicate that periodontal disease can be prevented by immunization against periodontal pathogens. However, it is also possible by immunization to induce periodontal destruction; i.e., the immune system has a destructive potential which should not be overlooked. In the future, the rat model may prove valuable for initial screening of antigen preparations and immunization regimens in the search for a periodontitis vaccine.

In vitro antimicrobial sensitivity of enteric rods and pseudomonads from advanced adult periodontitis

The prevalence and in vitro antimicrobial sensitivity of isolates of enteric rods and pseudomonads was examined in 844 adult periodontitis patients. These organisms were recovered from 13.5% of the study subjects. Ciprofloxacin exhibited the highest inhibitory activity of the 14 oral antimicrobial agents tested. Beta-lactam antibiotics were largely ineffective, and tetracycline failed to inhibit most Pseudomonas species. In vitro sensitivity data suggest that a subgingival microbiota comprising mainly streptococci would result from therapy that combined ciprofloxacin and metronidazole. Since streptococci may inhibit the growth of several putative periodontal pathogens, populations of "beneficial" streptococci in the periodontal pocket might constitute a very attractive therapeutic outcome. Controlled clinical studies are needed to clarify the possible role of ciprofloxacin in the treatment of destructive periodontitis.

Biochemical and serological characterization of Bacteroides intermedius strains isolated from the deep periodontal pocket

Fifty-one fluorescence-positive black-pigmented Bacteroides strains obtained from 51 patients with deep periodontal pockets (greater than 6 mm) were identified and characterized. Fifty of these strains were presumptively identified as Bacteroides intermedius according to the indole reaction. This was confirmed by further biochemical characterization. The 50 strains from diseased sites were then compared with 16 B. intermedius strains isolated from periodontally healthy individuals with no signs of destructive periodontal disease. Tests for antimicrobial susceptibility showed similar patterns for all 50 pocket-derived strains, except for one beta-lactamase-positive strain that was resistant to penicillin G and ampicillin. Forty-seven strains were tested for binding of three monoclonal antibodies defining three distinct serogroups of B. intermedius. Thirty-one strains belonged to serogroup I, three to serogroup II and thirteen to serogroup III. In comparison to the strains from the shallow periodontal pockets, serogroup I was significantly overrepresented in the patient group with periodontal disease. We conclude that saccharolytic black-pigmented Bacteroides species from deep periodontal pockets constituted, with very rare exceptions, a biochemically homogeneous but antigenically heterogeneous group of B. intermedius and that serogroup I is predominantly found in deep periodontal lesions.

Application of monoclonal antibodies to the detection of black-pigmented Bacteroides spp. in subgingival plaques by immunoslot blot assay

The aim of the present study was to assess the application of monoclonal antibodies to the detection of black-pigmented Bacteroides spp. in subgingival plaques by immunoslot blot assay. Subgingival plaque samples from adult periodontal patients were examined by immunoslot blot assay with monoclonal antibodies that specifically recognize Bacteroides gingivalis, Bacteroides intermedius serogroups I and II, and Bacteroides melaninogenicus. The assay can detect specifically these Bacteroides spp. in the subgingival plaques. Therefore, we investigated the distribution of these Bacteroides spp. in the subgingival plaques of patients classified by Russell's periodontal index. Reactivities of their plaques with monoclonal antibodies toward B. gingivalis and B. intermedius serogroup I were clearly related to the severity of the periodontal disease, but this was not the case with B. intermedius serogroup II and B. melaninogenicus. These results indicate that this immunoslot blot assay using monoclonal antibodies toward these Bacteroides spp. provides simple detection and monitoring of these organisms in periodontal patients.

Purification and characterization of alkaline phosphatase of Bacteroides gingivalis 381

Cell-associated alkaline phosphatase (ALPase) of Bacteroides gingivalis 381 was found in the outer part of the periplasmic space by using an ultracytochemical procedure. Cell-associated ALPase was solubilized by extraction with 1% Triton X-100, and the solubilized enzyme was purified 904-fold with 5.6% recovery by using affinity column chromatography for mammalian intestinal-form ALPase. The purified enzyme gave a single protein band that corresponded to the enzyme activity band on polyacrylamide gel electrophoresis preparations. A single protein band at a molecular weight of 61,000 was observed on sodium dodecyl sulfate-polyacrylamide gel electrophoresis preparations. The molecular weight of the native enzyme was estimated to be 130,000 by gel filtration with TSK-gel G3000SW. These findings indicate that B. gingivalis ALPase is a homodimer. The optimal pH of the enzyme was between 9.1 and 9.3 in the absence of divalent metal ions and was between 10.1 and 10.3 in the presence of manganese or zinc ions. The apparent km for p-nitrophenylphosphate was 0.037 +/- 0.003 mM (mean +/- standard deviation) at pH 9.2 in the absence of divalent metal ions and 0.22 +/- 0.02 mM at pH 10.2 in the presence of 1 mM manganese ions. Under both of the conditions described above, the purified enzyme was able to hydrolyze casein and O-phosphoserine, suggesting that B. gingivalis ALPase can act as a phosphoprotein phosphatase. ALPase that immunologically cross-reacted with the purified enzyme was found in the extracellular soluble fraction. This means that ALPase is released from the periplasmic space into the culture supernatant as a soluble form.

Effect of minocycline on subgingival plaque bacteria

The effects of minocycline on subgingival plaque samples from patients with chronic periodontitis were investigated in vitro. Minocycline concentrations as low as 1.0 microgram/ml inhibited 95.7% of the cultivable bacteria in the samples but 256 micrograms/ml was necessary to inhibit all of the cultivable bacteria in the samples. Although up to 99.9% of bacteria in the plaque samples were killed by a 6 h exposure to 8.0 micrograms/ml of minocycline, large numbers of viable bacteria remained. These results imply that adequate reductions in the numbers of viable subgingival plaque bacteria are unlikely to occur after exposure to minocycline at concentrations attainable in gingival crevicular fluid after systemic administration.

A new degradable controlled release device for treatment of periodontal disease: in vitro release study

The substantivity of a drug in the periodontal pocket is an important factor determining its effect on the subgingival flora. Therefore, one of the predominant factors in the development of a sustained release delivery device is the ability to control the rate of release of the drug. Previous studies have demonstrated the advantages of the local sustained release of chlorhexidine from nondegradable devices in the treatment of periodontal diseases. The aim of this study was to develop a degradable sustained release device composed of a cross-linked protein containing chlorhexidine as the therapeutic agent. The in vitro release profile of chlorhexidine from the degradable films was altered by the amount of chlorhexidine incorporated into the film, by the cross-link density of the polymer, and by the chlorhexidine salt used. The chlorhexidine in the final pharmaceutical preparation did not lose its antibacterial activity as was shown in an in vitro antibacterial test. This work demonstrates that the release of chlorhexidine from a degradable delivery system and the degradation of the matrix can be controlled by variation in the formulation. This presents a new dental drug delivery system that can be used as an adjunct in the treatment of periodontal diseases in the future. These studies enable us to choose the pharmaceutical formulations for clinical trials to be conducted testing the efficacy of this treatment modality.

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.

Evaluation of the activity of four antimicrobial agents using an in vitro rapid micromethod against oral streptococci and various bacterial strains implicated in periodontitis

The activity of various antibacterial agents (amoxicillin, josamycin, doxycycline and metronidazole) was established in vitro using a rapid micromethod. The activity of these agents, which are widely used in oral medicine, was evaluated against microorganisms responsible for periodontitis and bucco-dental infections. Their action against alpha-hemolytic streptococci (including pneumococci) which make up the majority of the indigenous oral flora was also tested. Amoxicillin was found to be effective against all the strains tested. Doxycycline was active against periodontal bacteria, but not against 50% of the streptococcal flora. Josamycin was found to be effective against streptococci, but appeared without effect on Eikenella corrodens and Actinobacillus actinomycetemcomitans. Metronidazole, inactive against streptococci, displayed greater activity towards the strict anaerobes. The use of these antibiotics for the treatment of bucco-dental infections, especially periodontitis, is discussed. For periodontitis and periodontal suppurations, antimicrobial agents present a valuable adjunct to local treatments such as scaling or rootplaning. This may prevent more serious infections such as endocarditis that can develop after tooth extraction.

Accessible sialic acid content of oral epithelial cells from healthy and gingivitis subjects

The purpose of the present study was to determine if there were differences in the quantity of accessible sialic acid on superficial epithelial cells collected from different areas of the mouth, and from healthy subjects with good oral hygiene, as compared to subjects with gingivitis. Superficial epithelial cells were collected by gently scraping the tongue dorsum, hard palate, free gingiva and buccal epithelium. The cells were washed and treated with clostridial neuraminidase to release accessible sialic acid; this was quantitated using a fluorometric assay. Buccal cells released an average of 62.6 ng sialic acid per 10,000 cells, which was nearly 3-fold more than cells from the hard palate (24.1 ng), free gingiva (21.9 ng), or tongue (15.4 ng). Buccal and free gingival cells collected from 5 healthy subjects had significantly higher levels of accessible sialic acid on their surface than cells collected from 5 subjects with gingivitis. These differences were significant at the p less than 0.001 and p less than 0.01 levels, respectively. The data obtained suggest that the oral hygiene status of an individual can influence the quantity of accessible sialic acid residues on oral epithelium; this would be expected to influence the attachment and colonization of bacteria which bind to sialic acid-containing receptors.

Subpopulations of lymphocytes in connective tissue from adolescents with periodontal disease

Mononuclear cell populations were studied in gingival biopsy specimens from adolescents (n = 10) with at least one periodontal pocket with an increased probing depth (greater than 5 mm). The marginal bone loss was measured on radiographs, subgingival plaque samples were collected from the lesions, and the microbial flora was identified. Specimens from gingivitis lesions (n = 5) were used as controls. The mononuclear cell populations in the specimens were detected by using monoclonal antibodies defining functional T-lymphocyte subpopulations, B lymphocytes, and monocytes. All gingival specimens from patients with increased probing depth showed large lymphocyte infiltrates, most of which were CD 3-antigen-positive cells (T lymphocytes). Few (2%) infiltrating T cells expressed receptors for interleukin-2. B cells were detected in most specimens from the periodontitis group and varied from less than 1% to 21%. This study indicates that lesions in adolescents with early signs of periodontitis are characterized predominantly by T-cell lesions with relatively few cell aggregates of B cells present.

Selective modulation of bacterial attachment to oral epithelial cells by enzyme activities associated with poor oral hygiene

The present investigation explored the hypothesis that elevated levels of certain enzymes in the gingival crevicular environment of individuals with poor oral hygiene and/or gingival inflammation may modify the surfaces of epithelial cells and thereby modulate the types of bacteria which attach and colonize. Buccal epithelial cells treated with neuraminidase and certain proteases were used as a model for study. Bacteria studied included Streptococcus sanguis and Streptococcus mitis which have been associated with gingival health, Actinomyces species which are increased in plaque associated with developing gingivitis, and Bacteroides gingivalis, Bacteroides intermedius, and Actinobacillus actinomycetemcomitans which are associated with destructive periodontal diseases. Treatment of epithelial cells with the enzymes studied produced selective effects on their receptivity for bacteria. Neuraminidase treatment of epithelial cells greatly reduced the attachment of all strains of S. sanguis and S. mitis studied. In contrast, the number of Actinomyces viscosus, A. naeslundii and A. israelii cells which attached was significantly increased. Neuraminidase treatment also appeared to enhance attachment of B. intermedius and B. gingivalis. Treatment of buccal cells with trypsin, chymotrypsin or papain also selectively affected bacterial attachment. Such protease treatment greatly reduced the numbers of streptococci and A. viscosus cells which attached, while the numbers of B. gingivalis and B. intermedius were significantly increased. Treatment of epithelial cells with preparations of lysosomal enzymes derived from human PMNs produced similar selective effects. The changes in bacterial adhesion observed by the enzyme treatments studied are consistent with the shifts in the composition of the gingival crevice flora which occur when oral hygiene is terminated and gingivitis develops.

Improved detection of oral spirochetes with an anaerobic culture method

A method for routine culturing of oral spirochetes was studied in periodontitis patients and subjects with healthy gingivae. Subgingival plaque bacteria, including oral spirochetes were cultured anaerobically using the steel wool jar method, the glove-box procedure and the plate-in-bottle method. They were also observed directly with a phase-contrast microscope. The number of colonies of recovered spirochetes was significantly higher with the plate-in-bottle method when Medium 10 (M10) or M10 supplemented with 10% rumen fluid was used. In almost all cases, spirochetes were detected with this culture method. The ratios of spirochetes from patient samples, cultured by the plate-in-bottle method, and of other microorganisms, cultured in Eggerth-Gagnon (EG) medium by the steel wool jar method, were almost identical of those observed by phase-contrast microscopy. These results indicate that it can be just as possible to culture certain oral spirochetes as other anaerobic bacteria.

Comparison of solid media for cultivation of anaerobes

Two commercial agar media for the cultivation of anaerobes were compared with four other media for their ability to support the growth of a wide range of anaerobes from clinical specimens of subgingival plaque. Fastidious anaerobe agar (FAA, Lab M) and anaerobe agar (GAA, Gibco) allowed better growth of the pure cultures than the other media. FAA recovered the highest numbers of bacteria from subgingival plaque specimens which were composed predominantly of anaerobes. GAA performed poorly with these samples. It is concluded that FAA seemed to be superior to the other media tested for the cultivation and recovery of anaerobes.

Similarities in the microfloras of root canals and deep periodontal pockets

Although not universally accepted, retrospective histological, roentgenological and microbiological studies have indicated that cross-infection can occur between infected pulps and deep periodontal pockets. This review provides examples of similarities in the microfloras of these adjacent oral sites, supporting the idea that infection spreads from one site to the other. The organisms most often involved are probably bacteroides, fusobacteria, eubacteria, spirochetes, wolinellas, selenomonas, campylobacter, and peptostreptococci. Important qualities of cross-infecting organisms may be the ability to survive in highly reduced environments and motility. Precautions should be taken to prevent in vivo seeding of such micro-organisms, particularly in compromised teeth and hosts.

Reproducibility of microbiological samples from periodontal pockets

Duplicate microbiological samples, were taken 1 week apart using the paper point technique from a total of 112 untreated periodontal pockets greater than 6 mm deep in 16 adult periodontal patients. Duplicate samples were also obtained from these sites 6 months following a therapy of oral hygiene instruction and supra- and subgingival debridement. The reproducibility of the total viable counts and the reproducibility of the proportions of various groups or species of microorganisms were studied from these duplicate samples. The results demonstrated an acceptable degree of reproducibility for the recovery of Actinobacillus actinomycetemcomitans and Bacteroides gingivalis. For the total viable counts and for the other investigated bacterial groups, including Bacteroides intermedius, unacceptable levels of reproducibility were observed.

Cloning of a Bacteroides gingivalis outer membrane protein gene in Escherichia coli

Gene banks of chromosomal DNA from Bacteroides gingivalis 381 were constructed using the bacteriophage replacement vector lambda L47.1. A clone encoding an outer membrane protein from B. gingivalis was identified by Western blot screening with antiserum raised against the outer membrane fraction of B. gingivalis 381 cells. The DNA insert contained within this phage was cloned into the plasmid vector pACYC184 to create the recombinant plasmid pMD123. An Escherichia coli transformant, MD123, containing pMD123 produced a protein having an apparent molecular weight of 40 kDa. The recombinant protein was purified, and amino acid analysis revealed the recombinant protein to have a relatively high content of hydrophobic amino acids (43.6%). Antiserum against the purified recombinant 40 kDa protein reacted with a polypeptide of similar size in the outer membrane fraction and vesicles of B. gingivalis.

The use of antimicrobial acrylic strips in the nonsurgical management of chronic periodontitis

Evidence to date has demonstrated the potential value of acrylic strips to deliver antimicrobial compounds into periodontal pockets. The present study was designed to evaluate further the therapeutic effect of antimicrobial acrylic strips in the management of chronic periodontitis. A total of 101 pockets in 69 patients were randomly treated with (1) chlorhexidine strips, (2) metronidazole strips, (3) tetracycline strips, (4) root planing, and (5) combined root planing and metronidazole strips. Immediately before and after treatment clinical measurements of disease were recorded over a three-month period. For all treatment groups significant improvements in clinical parameters were seen compared to control untreated sites but the most effective treatment was combined root planing and metronidazole and the least effective chlorhexidine. Although not significant, combined root planing and metronidazole also appeared to produce some adjunctive effects on clinical parameters compared to root planing alone. Antimicrobial acrylic strips appear useful treatments for chronic periodontitis, but should be used primarily as an adjunct to conventional root planing.

Current concepts of periodontal maintenance

Changing concepts and a more complete understanding of the aetiology of chronic marginal periodontitis allow a more rational approach to the treatment of patients with periodontal diseases. A sequence of treatment steps of increasing complexity is presented for the prevention of recurrence of chronic marginal periodontitis during the maintenance phase of treatment.

Purification and characterization of glycylprolyl aminopeptidase from Bacteroides gingivalis

A glycylprocyl aminopeptidase from cell extracts of Bacteriodes gingivalis 381 was purified 1058-fold by hydrophobic adsorbent, HPLC anion exchange, and HPLC gel filtration column chromatography. The final enzyme preparation was homogeneous with a molecular weight of 75,000 daltons by SDS-PAGE, and the isoelectric point was 6.2. The optimum pH of the enzyme was 8.0, and the enzyme activity was inhibited by DFP Ni2+ and Hg2+.

Clinical survey of Entamoeba gingivalis by multiple sampling in patients with advanced periodontal disease

A clinical survey of Entamoeba gingivalis was conducted in patients with advanced periodontal disease. A total of 100 specimens were taken from 10 patients (four females and six males) who were each sampled at 10 disto-facial random sites. The oral hygiene of the persons scored from good to fair to poor and very poor. The age of the test persons ranged from 20 to 68 years. All persons examined harbored E. gingivalis: the minimum prevalence was four sites positive out of 10 and the maximum prevalence was 10 sites positive out of 10 for the protozoan. It is recommended that for reliable testing of the presence of E. gingivalis at least five-10 different sites should be examined within the periodontium of each patient. Data reported earlier in the literature on the incidence of E. gingivalis--obtained after a single sampling per individual--are believed to be on average too low and, therefore, should be interpreted with caution.

The microbiology of HIV-associated periodontal lesions

2 intraoral lesions associated with human immunodeficiency virus (HIV) infection have recently been described: an atypical gingivitis and a rapidly progressive periodontitis. The microbiota associated with these gingival and periodontal lesions was investigated. Subgingival plaque samples were taken from 45 HIV-seropositive homosexual men and from 44 HIV-seronegative control subjects. Each sampled site was clinically and radiographically classified as HIV-associated gingivitis, HIV-associated periodontitis, healthy in an HIV-seropositive subject, or healthy, conventional gingivitis or classical periodontitis in a control subject. Plaque samples were examined by indirect immunofluorescence with polyclonal antisera to detect Bacteroides gingivalis, B. intermedius, Fusobacterium nucleatum, and Actinobacillus actinomycetemcomitans. Anaerobic culturing was used to detect black-pigmented Bacteroides species, Fusobacterium species, and A. actinomycetemcomitans to confirm the immunofluorescence findings. We detected B. gingivalis, B. intermedius, F. nucleatum, and A. actinomycetemcomitans in significantly more HIV-periodontitis sites (80, 65, 59 and 61% of sites, respectively) and HIV-gingivitis sites (61, 70, 52 and 52%, respectively) than in HIV-seropositive healthy and control sites (p less than 0.05). The results indicate that the microbiota found in HIV-periodontitis is similar to that of classical periodontitis. In contrast, however, the microbiota associated with HIV-gingivitis is strikingly different from that of conventional gingivitis. The similarity in the prevalence of periodontopathic organisms in both HIV-gingivitis and HIV-periodontitis suggests that the HIV-gingivitis lesion may be a precursor to the tissue destruction observed in HIV-periodontitis. Hence, early detection and treatment of the HIV-gingivitis lesion may prevent the rapid and extensive breakdown of periodontal tissues associated with HIV-periodontitis.

Use of strips containing tetracycline hydrochloride or metronidazole for the treatment of advanced periodontal disease

Strips containing tetracycline hydrochloride or metronidazole 25% in polyhydroxybutyric acid as a biodegradable polymer matrix, showed sustained release in simulated gingival fluid pH 6.6 at 37 degrees C. When evaluated in patients suffering from advanced periodontal disease, the greatest response to therapy was observed with tetracycline hydrochloride strips inserted into periodontal pockets at four-day intervals for 16 days, compared with an untreated control group. A reduction in plaque index, gingival index and pocket depth was observed. A favourable alteration occurred in the microbial flora of treated pockets with an increase in the proportion of cocci and decrease in gram-negative rods, fusiforms and spirochetes. Metronidazole strips or root-planning tended not to be as effective. The clinical improvement produced by each treatment was not maintained when treatment was terminated.

Periodontal conditions in adults with rheumatoid arthritis

Periodontal conditions among an adult population of 161 dentate patients with rheumatoid arthritis (RA) were compared with those of an age and sex-matched random sample of non-rheumatic subjects. The number of teeth and prevalence of dental plaque, calculus, gingivitis, and deepened periodontal pockets were recorded. Alveolar bone breakdown and the distribution of subjects according to severity of periodontal disease were also registered. There was a tendency towards better periodontal conditions among RA-patients, severe periodontal breakdown occurring less frequently among RA-patients (12%) than among the controls (16%). The RA-patients had less plaque and calculus than the control group, a finding which could indicate a difference in periodontal care.

Actinobacillus actinomycetemcomitans serotypes and leukotoxicity in Korean localized juvenile periodontitis

Actinobacillus actinomycetemcomitans is though to play an important role in the pathogenesis of localized juvenile periodontitis (LJP). Preliminary data suggested that the serotype distribution of A. actinomycetemcomitans in Korea and the United States differ. This study evaluated A. actinomycetemcomitans prevalence, serotype distribution, and leukotoxicity in Korean LJP patients by culture, enzyme-linked immunosorbent assay, indirect immunofluorescence, and lactate dehydrogenase release from polymorphonuclear leukocytes exposed to A. actinomycetemcomitans. A. actinomycetemcomitans occurred in 75% of LJP lesions and 6% of normal sites with approximately equal distribution of serotype a, b, and c. Single serotypes were isolated from nine patients while three patients harbored two serotypes either in the same or different disease sites. A. actinomycetemcomitans leukotoxicity occurred in 22% isolates with a 69% prevalence. Individual sites harbored both leukotoxic and non-leukotoxic strains with no serotype association. The distribution of serotypes and leukotoxic strains of A. actinomycetemcomitans in Korean LJP patients differed from those reported in the United States. This suggests that serotype b may not be more important in the pathogenesis of LJP.

Modulation of colonization by black-pigmented Bacteroides species in squirrel monkeys by immunization with Bacteroides gingivalis

Periodontal diseases are inflammatory responses thought to be triggered by specific microorganisms colonizing in the gingival crevice. Theoretically, periodontal diseases could be prevented if the etiologic organisms were not allowed to colonize the subgingival area. The humoral immune response is one mechanism which may modulate bacterial colonization in the gingival crevice. To test the effect of systemic humoral immunity on subgingival colonization by bacteria, squirrel monkeys (Saimiri sciureus) were immunized with Bacteroides gingivalis, a black-pigmented Bacteroides sp. and putative periodontal pathogen. Immunized and sham-immunized monkeys were orally inoculated with 10(10) viable B. gingivalis during ligation of five teeth in one quadrant with bacterium-soaked suture material and distribution over the entire dentogingival margin. Immunization resulted in an increased level of immunoglobulin G anti-B. gingivalis in serum and was associated with a strong trend toward a statistically significant reduction in colonization of the gingival crevice by black-pigmented bacteroides.

The interleukin concept and the periodontal diseases

The interleukins are hormone-like substances found at sites of inflammation such as in rheumatoid arthritis and periodontal disease. The present article analyzes a hypothetical mechanism of periodontal pathogenesis, whose etiology is still unclear despite its high prevalence.

Effect of periodontal status of rotary electric toothbrushes vs. manual toothbrushes during periodontal maintenance. II. Microbiological results

We compared the use of a rotary electric toothbrush with conventional toothbrushing for their effectiveness in modulating the subgingival microbiota. Forty subjects who had received periodontal treatment for moderate to advanced periodontitis and were on 3-month periodontal maintenance were divided into two equal groups matched for age and sex. One group used only the rotary tooth cleaner and the other group used conventional toothbrushing, dental floss, and toothpicks for 12 months. Subgingival plaque samples (two sites per patient) were taken from 10 subjects per group at baseline, 6 months, and 12 months and analyzed for percentage of obligate anaerobes and colony-forming units of black-pigmented Bacteroides, Fusobacterium, Actinomyces, Streptococcus, and Veillonella spp. The percentage of spirochetes and motile rods was determined by darkfield microscopy. Results showed that levels of obligate anaerobes, Fusobacterium, and Actinomyces and percentage of spirochetes and motile rods decreased significantly (P less than 0.05), while levels of Streptococcus spp. increased (P less than 0.05) for both groups. However, there was no significant difference between the two groups, indicating that the rotary tooth cleaner and conventional toothbrushing are equally effective in controlling gingivitis and fostering a less pathogenic microflora.

Concentrations of fibronectin in the sera and crevicular fluid in various stages of periodontal disease

While fibronectin (FN) has previously been demonstrated to be present in gingival crevicular fluid (GCF), its quality and quantity has not been reported. Since this information is relevant for ongoing studies on the use of FN for gingival reattachment, we performed these measurements and compared plasma levels in healthy subjects, patients with gingivitis and periodontitis, and in patients undergoing maintenance therapy. Plasma and GCF samples were obtained from 4 sites in each subject using a Periotron to permit quantification of samples. FN concentrations were determined in a microELISA using hyperimmune anti-FN antibody. Purified FN served as a reference for quantification. The functional activity of each sample was assessed by examining the natural affinity of FN for gelatin. Subjects with gingivitis and those in maintenance had significantly depressed levels of plasma fibronectin. While little fibronectin could be detected in the GCF of healthy sites regardless of patient category, examination of the most diseased sites in each group revealed that the concentration of FN in the GCF was highest in health and reduced when there was gingival inflammation. In no case was GCF FN found to be biologically active.

A common antigen of Treponema denticola and other Treponema species detected by monoclonal antibody

Murine monoclonal antibodies against Treponema denticola were produced. One monoclonal antibody (MSA257) reacted with 34,000 dalton antigens of all T. denticola strains, including ATCC strains and our isolates. This monoclonal antibody also reacted with antigens of other treponema strains tested.

The effect of 2% chlorhexidine digluconate irrigation on clinical parameters and the level of Bacteroides gingivalis in periodontal pockets

Eight patients with moderate periodontitis volunteered to participate in a study to assess the effect of subgingival 2% chlorhexidine irrigation, with and without scaling and root planing, on clinical parameters and the level of Bacteroides gingivalis in periodontal pockets. Each quadrant was required to have at least one site with a probing depth of 6 mm or greater and bleeding on probing. The patients were treated following a randomized four quadrant design: one quadrant received no treatment; a second quadrant received scaling and root planing only; a third quadrant received chlorhexidine irrigation only; the fourth quadrant received scaling and root planing, plus chlorhexidine irrigation. Sites to receive chlorhexidine were irrigated at 0, 1, 2, and 3 weeks. Clinical and microbiological indices were measured and recorded at 0, 5, 7, 11, and 15 weeks. The clinical parameters measured included; Plaque Index (PI), Gingival Index (GI), probing depth (PD), Bleeding Tendency (BT), and attachment level (AL). The attachment level was measured using an occlusal stint as a fixed reference point. The level of Bacteroides gingivalis was measured by labeling the plaque sample with a polyclonal fluorescent antibody. The plaque smear was then read using a fluorescent microscope at 1000 magnification. The Spearman Rank-Order Correlation was used to determine the relationship between parameters at baseline. The effects of the treatment groups were compared using the Neuman-Keuls Multiple Comparison Technique. The results showed that a positive correlation existed between B. gingivalis (rs = 0.68) and Bleeding Tendency and between P1I (rs = 0.77) and GI.(ABSTRACT TRUNCATED AT 250 WORDS)