Subgingival microflora and periodontal disease

Pathogenesis of periodontitis

Periodontitis is an inflammatory disease of the periodontium which is characterized by a progressive destruction of the tissues supporting the tooth. Its primary etiology is an ill-defined series of microbial infections which may be composed of only some of the more than 300 species of bacteria currently recognized in the oral cavity. The disease is currently considered to progress as periodic, relatively short episodes of rapid tissue destruction followed by some repair, and prolonged intervening periods of disease remission. Despite the apparent random distribution of episodes of disease activity, the resulting tissue breakdown exhibits a symmetrical pattern of alveolar bone loss and pocket formation which is common to several forms of periodontitis, although the distribution of the most affected teeth and surfaces may vary among diseases (e.g., juvenile periodontitis versus adult periodontitis or rapidly progressive periodontitis). Several reports have indicated that bacterial cells can be found in the pocket wall of periodontitis lesions. The translocation of bacteria into the tissues from the pocket environment is quite common, as evidenced by the common occurrence of bacteremias in patients with periodontitis following relatively minor events such as chewing and oral hygiene procedures. However, it is important to distinguish between the passive introduction of bacteria into periodontal tissues and frank invasion as might occur in an acute infection, since the pathological implications may be quite different.

Indicators of periodontal disease activity: an evaluation

It is becoming increasingly apparent that the traditional clinical criteria are inadequate for: determining active disease sites in periodontitis, monitoring quantitatively the response to therapy or measuring the degree of susceptibility to future breakdown. In an attempt to develop objective measures, a wide variety of studies have been undertaken using saliva, blood, plaque and gingival crevicular fluid (GCF) as the specimen source. Examination has included: specific bacteria and their products; host cells and their products (enzymatic and antibacterial, both immunologic and non-immunologic); products of tissue injury derived from local epithelial and connective tissues and bone. Although most of the work to date has failed to provide reliable aids to the clinician, refinements in techniques for sampling and the availability of more sophisticated analytic techniques give cause for optimism. Methods proposed for detection of disease-associated bacteria in subgingival plaque vary in their sensitivity and specificity. Dark field microscopy shows some correlation with existing disease; however, the limited specificity of this method imposes severe restrictions on its usefulness. Highly specific polyclonal and monoclonal antisera to suspected pathogens Bacteroides gingivalis and Actinobacillus actinomycetemcomitans have been developed and improved methods of identification of these microbes in plaque by ELISA immunofluorescence and flow cytometry are under development. With respect to the host response, a strong correlation between antibody patterns to specific bacteria and periodontal disease categories appears to be emerging. Although most studies have focused on serum antibody derived from peripheral blood, a shift to detection of local antibody response appears to be likely. Techniques of measurement that are exquisitely sensitive have been developed for detection of major immune recognition proteins such as antibody and complement in crevicular fluid. Research efforts attempting to correlate local antibody response to local disease activity are underway. Measurement of GCF flow rate, endotoxin, H2S, butyrate and a variety of enzymes (e.g., collagenase, arylsulfatase, B-glucuronidase) show good correlation with levels of gingivitis. In periodontitis, the most promising markers of tissue breakdown are prostaglandins of the E series, the enzymes collagenase and aspartate aminotransferase, sulfated glycosaminoglycans, osteoclastic activating factor and bone resorptive capacity of crevicular cells. Assay of the migration of crevicular leucocytes in vivo can serve as an indicator of a defect in host resistance.(ABSTRACT TRUNCATED AT 400 WORDS)

The osteoclast and periodontitis

The osteoclast may play an important rŏle in the variable rate of osseous destruction seen in periodontitis. Current understanding of various aspects of the osteoclast may help explain this fact. This review paper will first look at two theories of cell origin of the osteoclast: the multipotential osteoprogenitor cell theory and the hemopoietic stem cell theory. Next, ultrastructural features characteristic to the cell such as the ruffled border, clear zone, and lysosomal system, will be discussed. Thirdly, current and proposed theories on the actual mechanism of bone degradation are considered. This includes the one-cell theory and the two-cell theory. Finally, elements which activate the osteoclast are enumerated and their delicate interplay is outlined. In the context of this information, pathways found in the periodontal lesion (microbial agents, inflammatory cells and their products) which attract and activate elements of the osteoclastic system are discussed.

Microbial populations and active tissue destruction in experimental periodontitis

Although specific subgingival microflora are being associated with active tissue destruction in periodontitis, little information exists on the relationship between subgingival flora and histological evidence of tissue destruction. The present study was undertaken to explore these relationships during experimental marginal periodontitis in squirrel monkeys. In 4 squirrel monkeys, experimental periodontitis was induced around bicuspids and molars using silk ligatures. The buccal part of the subgingival ligature was removed for bacterial sampling 3, 7, and 14 days after ligature placement. Dark-field microscopy was used to quantify motile forms, spirochetes, straight and curved rods, filaments, cocci and fusiforms. Subgingival plaque prior to periodontitis induction was dominated by cocci, but fusiforms and straight rods were also present. Spirochetes, filaments, curved rods and motile forms were absent. 3 days after induction of periodontitis, there were marked increases in spirochetes, motile forms, filaments, curved and straight rods. The proportions of coccoids and fusiforms decreased. The bacterial proportions stayed at approximately the same levels through 7 and 14 days. Histometric quantification of periodontal destruction showed loss of connective tissue attachment and crestal alveolar bone. A positive correlation was found between periodontal tissue destruction and both total number of subgingival bacteria and spirochetes.

Human immune responses to oral microorganisms: patterns of systemic antibody levels to Bacteroides species

Human systemic antibody levels to oral members of the Bacteroides genus were assessed with an enzyme-linked immunosorbent assay. Antibody levels to B. gingivalis, two homology groups of B. intermedius, B. melaninogenicus, B. denticola, B. loescheii, B. corporis, B. oralis, B. buccae, and B. gracilis were determined in subjects with localized juvenile periodontitis, advanced destructive periodontitis, or adult periodontitis and in normal persons. Significantly elevated serum immunoglobulin G (IgG) antibody levels to B. gingivalis were seen in adult and advanced destructive periodontitis patients. Serum IgM and IgA antibodies were increased in diseased versus normal subjects, whereas negligible levels of serum IgE antibody were detected to this microorganism. Serum IgG antibody levels to B. intermedius were increased in advanced destructive periodontitis patients; however, the frequency of elevated responses were similar among the groups. Extreme antibody levels to the other Bacteroides spp. were occasionally observed in this population. Additionally, all of the elevated levels were found in diseased patients. Distribution analyses of the antibody levels indicated that most patients exhibited a pattern of elevated antibodies to a limited number of the oral Bacteroides spp. The results suggested that elevated systemic antibody levels to oral Bacteroides spp. are more frequently found in periodontal disease patients. These antibody responses presumably reflect a colonization of the patients. The distribution of the responses may indicate the potential pathogenicity of the microorganisms and is consistent with distinctive host-parasite interactions in this disease.

Depth of penetration in periodontal pockets with oral irrigation

The purpose of this study was to determine the effectiveness of the Water Pik oral irrigator as a vehicle for delivering an aqueous solution into periodontal pockets. Plaque-disclosing dye diluted with sterile saline solution was applied with the irrigator toward the gingival margins of teeth at 90 degrees and at 45 degrees prior to their extraction. The mean % penetration measured between a reference notch at the gingival crest and the periodontal ligament at the bottom of the pocket showed no statistical difference between the two angles of application. Penetration ranged from 44% to 71%, the lowest being into pockets 4-7 mm; higher mean penetration was noted in both subgroups 0-3 and greater than 7 mm. No statistical difference was found between proximal and facial or lingual surfaces, maxilla and mandible, existence of tooth contact, and proximal tissue contour or consistency. The mean % penetration was independent of pocket depth (chi 2 analysis). Correlation between pocket depth and mean penetration was low for all but one subgroup (90 degrees application and pockets greater than 7 mm). The results suggest that the oral irrigator will deliver an aqueous solution into periodontal pockets and will penetrate on average to approximately half the depth of the pockets.

Repair of an extensive periodontal defect after tetracycline administration. A case report

A pathologically migrated maxillary central incisor tooth with a poor periodontal prognosis was treated successfully with conventional periodontal therapy. After almost 4 years, an extensive periodontal lesion developed on the same tooth and extraction was recommended. The patient did not comply and the acute symptoms disappeared after the administration of 1 gm of Tetracycline a day for 2 weeks. Although no definitive periodontal therapy was done, complete resolution of the lesion occurred with the healing of the structures of the periodontium and a dramatic reduction in mobility of the tooth. Antibacterial therapy could be an effective means of treating some periodontal lesions once a more exact and direct association is established between the various clinical forms of periodontitis and specific periodontal or groups of pathogens.

The antimicrobial and clinical effects of a single subgingival irrigation of chlorhexidine in advanced periodontal lesions

The antimicrobial effects of subgingival chlorhexidine (CH) irrigations on the pathogenic flora in advanced periodontal lesions were assessed. Changes in the patterns of colonization within the subgingival sites were monitored by differential dark-field microscopy, in 16 patients, over a period of 10 weeks. In addition, changes in the clinical parameters of the diseased sites were also monitored. Initial base-line evaluations were made for both the clinical and microbiological parameters. 4 sites of moderate to advanced periodontal disease were selected in each patient. These were randomly irrigated with a single dose of either 0.2% CH gel, 0.2% CH solution, or physiological saline, while 1 site was left as a control. The patients were seen weekly, until the 5th week, then at the 7th and 10th weeks. At each appointment, a microbiological sample was taken from the subgingival region of each site, together with an assessment of the clinical indices. Results indicated that a single irrigation of an 0.2% solution of CH or 0.2% CH gel had a marked effect in decreasing the % of spirochaetes and, to some extent, motile bacteria. There was a concomitant shift in colonization to cocci, fusiform and filamentous organisms in pockets that were irrigated; this coincided with a reduction in the % of bleeding sites. Various patterns of colonization were observed which have been described and may assist in differential dark field (DDF) monitoring of lesions. Bleeding on blunt probing was found to be correlated with a flora dominated by spirochaetes. No other correlations were found over the 10-week period between the other parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum IgG antibodies to lipopolysaccharides in various forms of periodontal disease in man

Serum IgG antibody titres to lipopolysaccharides (LPS) from two strains of Actinobacillus actinomycetemcomitans were significantly elevated in juvenile periodontitis compared with other types of periodontal disease and with controls (p less than 0.05). The highest antibody titres to Bacteroides gingivalis LPS were in juvenile periodontitis, but this difference was significant only against the control group (p less than 0.01). In adult mild periodontitis there were higher antibody levels to LPS from Veillonella parvula compared with all other groups and controls (p less than 0.05). The possibility that high antibody titres to LPS from A. actinomycetemcomitans may play a protective role in juvenile periodontitis needs further investigation.

Serum and gingival fluid antibodies as adjuncts in the diagnosis of Actinobacillus actinomycetemcomitans-associated periodontal disease

Serum antibody titers to Actinobacillus actinomycetemcomitans were measured in 200 subjects by an enzyme-lined immunosorbent assay (ELISA) using whole microorganisms as antigen. Comparisons were made between titers found in periodontally normal subjects and titers in subjects with localized juvenile periodontitis (LJP), postlocalized juvenile periodontitis, generalized juvenile periodontitis or adult periodontitis. It was found that titers to all three serotypes of A. actinomycetemcomitans were elevated in LJP patients' sera, while serum antibody levels in other diseased groups were not significantly elevated to any of the serotypes. Patient sera were also examined for serum antibody to oral Haemophili previously shown to cross-react with A. actinomycetemcomitans. Similar antibody titers were found in both normal subjects and in patients with various forms of periodontal disease to Haemophilus aphrophilus, H. influenzae and H. parainfluenzae. The A. actinomycetemcomitans antibodies which were elevated in LJP patients could not be correlated with antibody titers to cross-reacting Haemophili, suggesting that these antibodies are A. actinomycetemcomitans-specific. Serum antibody responses in six of the LJP patients were assessed to autologous strains of A. actinomycetemcomitans. Each patient was found to be infected with only a single serotype of A. actinomycetemcomitans, and specific antibodies to the infecting serotype were found in the patients' sera. In families, the LJP patients had significantly elevated IgG, IgA and IgM serum antibody titers to A. actinomycetemcomitans, while the IgG and IgA antibody titers in periodontally normal siblings were at levels comparable to those found in normal subjects. However, IgM serum antibodies were elevated in the periodontally normal siblings of LJP patients suggesting that the formation of IgM antibodies to A. actinomycetemcomitans may precede the clinical appearance of localized juvenile periodontitis. Gingival crevicular fluid and serum antibody levels to A. actinomycetemcomitans were compared in LJP patients. Comparable titers of IgG, IgA and IgM antibodies were found in serum and gingival fluid in most subjects; however, gingival fluid samples sometimes showed higher titers than serum, likely resulting from local antibody synthesis. The value of serum antibody determinations to A. actinomycetemcomitans in the diagnosis of Actinobacillus-associated periodontitis was also assessed. The predictive value of a positive test (significantly elevated anti-A. actinomycetemcomitans IgG) was 86%, while the specificity was 89%.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of short-term administration of metronidazole on the subgingival microflora

The effect of a 5-day course of systemic metronidazole was investigated in 11 recall maintenance patients over a period of 3 months. Crevicular fluid flow, bleeding on probing, pocket depth, and composition of the subgingival microbiota as observed by dark-field microscopy, were measured. The study design allowed patients to act as their own controls. At baseline 1 (day 0), each patient had a randomly assigned quadrant scaled and root-planed, and received oral hygiene instruction. Microbiological and clinical parameters were measured at baseline 1 (before treatment) and at 3, 6, and 12 weeks in both the root-planed and a designated no-treatment quadrant. At baseline 2 (12 weeks), the contralateral quadrant was scaled and root-planed, and the oral hygiene instruction was reinforced. At this appointment, each patient was given 15 metronidazole tablets (250 mg), 1 to be taken 3 times per day for 5 days. At the end of this period, patients were seen 1-2 h after taking their last tablet, and blood and crevicular fluid samples were taken to determine the concentration of metronidazole by microbiological assay in the serum and crevicular fluid. Microbiological and clinical parameters were measured at baseline 2 (before treatment) and at 13, 15, 18, and 24 weeks in both the root-planed and designated non-root-planed (metronidazole only) quadrants. Results demonstrated that in this group of recall maintenance patients, metronidazole was no more effective than root-planing alone in reducing the relative % of total motile organisms and spirochetes in 5-8 mm pockets. Crevicular fluid flow was, however, significantly reduced for 11 weeks; serum and crevicular fluid levels of metronidazole were similar 1 to 2 h after drug ingestion.

Local antibody responses in periodontal diseases

The relationship between local and systemic host antibody responses, colonization of subgingival plaque by periodontal disease-associated microorganisms and the progression of periodontal disease was assessed in 61 patients. Serum antibody levels to a battery of oral microorganisms were determined by an enzyme-linked immunosorbent assay (ELISA), and an organism to which each patient exhibited a significantly elevated IgG response was chosen for further study. To detect the presence of the specific microorganism, plaque samples were obtained and examined using a seroELISA. Static crevicular fluid (SCF) samples were also obtained from all teeth and analyzed for IgG antibody to the homologous organism. A modification of the standard ELISA using biotin and avidin allowed a 5- to 10-fold increase in sensitivity for detection of IgG antibody in serum and SCF. Comparison of the distribution of elevated SCF antibody and the presence of the corresponding microorganism in each patient showed that the proportion of agreement was 54 to 78% in the samples. Schematic representation of the temporal relationship between the organism, the host response and disease activity were prepared to explain the results obtained in investigations of these parameters and to provide a testable hypothetical framework for future studies.

Functional role of interleukin 1 in periodontal disease: induction of interleukin 1 production by Bacteroides gingivalis lipopolysaccharide in peritoneal macrophages from C3H/HeN and C3H/HeJ mice

Hot phenol-water-extracted lipopolysaccharide (LPS) from Bacteroides gingivalis 381 was purified by Sephadex G-100 chromatography with Tris buffer supplemented with sodium deoxycholate and EDTA (B-LPS). In the present study, B-LPS was examined for its ability to induce interleukin 1 (IL-1) production, a mitogenic response, and macrophage activation in LPS high-responder C3H/HeN and low-responder C3H/HeJ mice. A significant increase in IL-1 production was observed in C3H/HeN and C3H/HeJ peritoneal macrophages treated with various doses (1.0 to 50 micrograms/ml) of B-LPS. IL-1 production by C3H/HeN macrophages treated with B-LPS (10 micrograms/ml) was about seven times greater than that by C3H/HeJ macrophages. However, the IL-1 production induced by B-LPS (10 micrograms/ml) in C3H/HeN macrophages was four times lower compared with that induced by Escherichia coli O111 B4 LPS. Also, a significant increase in IL-1 production was found in human monocytes stimulated with B-LPS. That B-LPS-induced IL-1 exhibits some molecular weight heterogeneity was indicated from Sephadex G-75 gel filtration profiles. A significant, high mitogenic response by whole spleen cells with 1 X 10(5) to 5 X 10(4) cells of either mouse strain per well treated with B-LPS (10 to 50 micrograms/ml) was observed. However, the response of C3H/HeJ mice was less than that of the C3H/HeN strain. Also, glucose consumption assays indicated that enhanced macrophage activation occurred in C3H/HeN but not in C3H/HeJ mice treated with B-LPS. In light of recent studies showing that IL-1 stimulates bone resorption in a mouse calvaria system and collagenase production in fibroblasts, we suggest that B-LPS-induced IL-1 may play a significant role in the pathogenesis of adult periodontal disease.

Clinical and laboratory studies of a family with a high prevalence of juvenile periodontitis

The form of periodontitis with onset at puberty and affecting predominantly the first molars and incisors is called juvenile periodontitis (JP). The disease has been the object of intense study because from its analysis may come insights into understanding other, more common, forms of periodontitis. We recently had the opportunity to study an unusual family in which both parents developed JP in their teens. We did clinical examinations, measured leukocyte chemotaxis, analyzed the pocket microflora, looked for serum antibodies against a large panel of putative periodontal pathogens and correlated the results. The couple had two affected and two unaffected children. One of the unaffected children was not available for study. Neutrophil chemotaxis was abnormal in both parents and in the two affected children, but not in the unaffected child. Actinobacillus actinomycetemcomitans accounted for 17.5% of the pocket flora isolated from one affected child and 2.5% of that from the unaffected child, but was not detected in the remaining family members. Antibodies specific for A. actinomycetemcomitans, Hemophilus aphrophilus and Eikenella corrodens were present in the serum of both affected children and for Capnocytophaga sputigena and C. ochracea in the father, but no antibodies directed against any of the species studied were found in the mother and the unaffected child. The distribution of disease in this family was more compatible with an X-linked dominant than with an autosomal recessive mode of inheritance. The correlations among presence or absence of disease, abnormal neutrophil chemotaxis and presence of serum antibodies reacting with A. actinomycetemcomitans were excellent.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of supragingival plaque control on the subgingival microflora

The effect of plaque control on the apical microflora of deep periodontal pockets was studied. 8 subjects exhibiting signs of chronic periodontitis were chosen for the study, each subject having at least one pocket greater than 6 mm. These subjects were placed on a plaque control programme consisting of 3 visits, during which oral hygiene instructions were given. On two visits, the teeth of these subjects were scaled and polished. Bacteriological samples from the apex of a deep pockets from each subject were collected before the commencement of the plaque control programme and again at 8 and 16 weeks after the last scale and polish. No significant difference in the microbial flora was observed before and after plaque control, but marked fluctuation in bacterial composition was noted at the 3 samplings. It was concluded that supragingival plaque reduction was not sufficient to produce significant changes in the subgingival plaque composition of deep periodontal pockets.

Bacteroides endodontalis and other black-pigmented Bacteroides species in odontogenic abscesses

Twenty-eight odontogenic abscesses were examined for the presence of black-pigmented Bacteroides spp. Of the 28 samples, 26 were found to contain one or more species of black-pigmented Bacteroides. Abscesses were divided into three categories according to the tissue of origin: endodontal, periodontal, and pericoronal. Four abscesses which developed after extraction were also examined. It was found that Bacteroides endodontalis, a newly described species of asaccharolytic black-pigmented Bacteroides, was isolated almost exclusively from periapical abscesses of endodontal origin. B. intermedius proved to be the most frequently isolated species in all of the samples. B. gingivalis was present in all of the periodontal abscesses studied, as well as in two endodontal abscesses. B. melaninogenicus was recovered once from a pericoronal abscess. Precautions for the isolation of B. endodontalis are discussed.

Subgingival spirochete and leukocyte counts as indicators of response to therapy

The aim of this study was to determine whether changes in probing attachment levels are related to subgingival spirochete or leukocyte counts in periodontal pockets. Following initial clinical recordings and therapy consisting of oral hygiene instruction and root debridement, the probing attachment levels of proximal sites of 120 single-rooted teeth in 7 patients were measured every 3 months for 12 months. The measurements of each site were subjected to regression analysis, which determined whether the site was deteriorating, improving, or non-changing. Subgingival washings were taken of 19 deteriorating, 22 improving, and 127 non-changing sites to determine the number and % of spirochetes and the number of leukocytes at each site. Improved probing attachment levels were associated with reduced numbers of spirochetes and leukocytes. However, the ranges of individual measurements of subgingival washing variables overlapped considerably between groups. Spirochete and leukocyte counts related better to the 12-month probing depths than to changes in probing attachment levels during the preceding 12 months. These findings suggest that none of the tested subgingival washing parameters are suitable indicators of changes in attachment levels on an individual site basis.

Gram negative species associated with active destructive periodontal lesions

Apical subgingival plaque samples were taken from 19 subjects exhibiting active destructive periodontal disease. The predominant cultivable Gram negative species from 50 active sites were compared to 69 inactive sites of comparable pocket depth and attachment level loss. Active disease sites were chosen which showed a significant loss of attachment within a two-month interval. Proportions of Gram negative rods were higher in active periodontal disease sites than in inactive sites. Species which were found to be significantly elevated only in active sites were Bacteroides intermedius, "fusiform" Bacteroides, Actinobacillus actinomycetemcomitans and Wolinella recta. Fusobacterium nucleatum, Capnocytophaga gingivalis and Eikenella corrodens were found in significantly increased proportions in active sites of some subjects and inactive sites of others.

Assessment of serum antibody patterns and analysis of subgingival microflora of members of a family with a high prevalence of early-onset periodontitis

In a study of members of a large family with a high prevalence of early-onset periodontitis, we sampled the subgingival microflora and characterized 40 isolates from each sample. We surveyed serum samples by enzyme-linked immunosorbent assay for antibodies reacting with any of a panel of 21 periodontal bacteria. The mother and 7 of her 13 children had early-onset periodontitis. Bacteroides gingivalis was not detected in the subgingival flora of any affected or unaffected family member, and Actinobacillus actinomycetemcomitans was isolated from only one affected child. Capnocytophaga ochracea was isolated from five of seven affected children and from none of their normal siblings. We found no significant differences among the floras from family members who had rapidly progressive, juvenile, and prepubertal forms of periodontitis. Elevated levels of serum antibody reacting with one or more of the bacteria tested were found in all family members with disease, but in only one periodontally normal family member. Both children with prepubertal periodontitis had antibodies reacting with C. sputigena, a species not found in their subgingival floras, but with none of the other bacteria tested. All remaining affected family members had antibodies to one or more serotypes of A. actinomycetemcomitans, and four had antibodies reacting with additional bacteria, including C. sputigena, Eikenella corrodens, Fusobacterium nucleatum, and Haemophilus aphrophilus. Sera from patients contained antibodies specific for putative periodontal pathogens not found in their pocket flora, and conversely, putative periodontal pathogens for which no serum antibodies were found frequently comprised a large proportion (10% or more) of the pocket flora. In no case were both the bacterium and its antibody found. These observations are suggestive of sequential infection in the early-onset forms of periodontitis and of induction of protective immunity against reinfection by the same microorganism.

Morphology of polymorphonuclear neutrophils during periodontal disease in the cynomolgus monkey

The polymorphonuclear neutrophil (PMN) appears to be an important cell in the protection of the host from pathogenic periodontal micro-organisms. The purpose of the present histological studies was to observe the emigration of the PMN from the gingival vessels to the periodontal pocket during gingivitis and ligature-induced periodontitis in the cynomolgus monkey. 2 adult female monkeys were treated by application of a silk ligature around selected posterior teeth. After 9 weeks, the monkeys were perfused and block sections of both ligated (early periodontitis) and non-ligated (gingivitis) sites were obtained, cut into smaller blocks containing a single interdental area (N = 15 for periodontitis, N = 5 for gingivitis) and processed for light and electron microscopic observations. Morphologically, no differences in PMNs between gingivitis and periodontitis were observed and therefore the following description applies to both disease states. In the vessels, the endothelial cells appeared to be actively involved in PMN emigration, maintaining long processes which surrounded the PMNs. Within the connective tissue, the PMNs maintained their typical morphology which included polylobated nuclei and numerous lysosomal granules. Many intact PMNs were observed intercellularly within the connective tissue and the epithelium. Within the periodontal pocket, a multilayer of PMNs surrounded the plaque mass. Cells with numerous bacteria-containing phagolysosomes were observed with increasing frequency as they approached the plaque. Deeper within the bacterial deposit, PMNs were seen in varying stages of degeneration. These histologic studies, when interpreted in the light of reports of severe, rapidly-progressive periodontitis in patients with PMN disorders, suggest that the interaction of PMNs with bacterial plaque may serve to maintain a defensive boundary which protects the host tissues from irreversible destruction.

Generalized juvenile periodontitis, defective neutrophil chemotaxis and Bacteroides gingivalis in a 13-year-old female. A case report

Host immune responses and the predominant subgingival microflora were evaluated in a 13-year-old female exhibiting a severe form of generalized juvenile periodontitis. The patient's neutrophils were chemotactically depressed but exhibited a normal oxidative capacity. Serum IgG antibody to Bacteroides gingivalis and to Actinobacillus actinomycetemcomitans serotype c were elevated. Significantly, B. gingivalis constituted 8 to 16% of the cultivable microflora and 13 to 20% of the total cell count in subgingival plaque samples obtained from five out of five periodontally diseased sites examined. It was not detectable in a healthy site. A. actinomycetemcomitans was recovered in small numbers from all subgingival plaque samples taken. The present study provides additional evidence for an etiologic association between B. gingivalis and generalized juvenile periodontitis.

Ultrastructure of developing subgingival plaque in beagle dogs

The aim of this study was to describe the ultrastructure of developing subgingival plaque. In 6 beagle dogs, healthy gingiva prevailed after a pre-experimental period of intensive plaque control. At the start of the experiment, all oral hygiene measures were withdrawn. Biopsies comprising buccal gingiva and adjacent dental tissues were obtained from premolars and molars on days 0, 4, 7, 21, and 28 and processed for electron microscopy. Sections of day 0 exhibited a junctional epithelium in close contact with the tooth and absence of subgingival aggregations of bacteria on the tooth surface. For each of the subsequent periods studied, some sections did not exhibit subgingival plaque. In the remaining sections with subgingival plaque, almost all bacteria appeared in aggregates attached to the tooth surface. The number of bacteria at the orifice of the gingival sulcus increased with time. Further apically, the micro-organisms formed either a continuous layer of even thickness or, more frequently, discrete microcolonies along the tooth surface. The bacteria comprised practically entirely Gram-negative cocci, rods or spirochetes. The latter were present either mixed with the other types in the discrete microcolonies or constituted the bulk of the continuous layer of plaque. In the apical part of the subgingival plaque, a shift from Gram-negative cocci and rod during the early stages of gingival inflammation, to a predominance of spirochetes in later stages was noted. The study shows that in dogs, starting from a plaque- and gingivitis-free baseline, a predominantly Gram-negative subgingival flora may form within a few days after withdrawal of all oral hygiene measures and that a shift in the bacterial composition of the subgingival plaque takes place during a 4-week period of no oral hygiene.

Differentiation between major species of the Actinobacillus--Haemophilus--Pasteurella group by gas chromatography of trifluoroacetic acid anhydride derivatives from whole-cell methanolysates

A method based on whole-cell methanolysis and trifluoroacetic acid anhydride derivatization was developed for routine laboratory differentiation between isolates from the Actinobacillus--Haemophilus--Pasteurella group. All species, except Haemophilus aphrophilus, contained D-glycero-D-mannoheptose, although in varying concentrations. The distribution of this sugar could be used to distinguish H. aphrophilus from Actinobacillus actinomycetemcomitans, H. paraphrophilus, H. influenzae type b, Pasteurella haemolytica, P. multocida and P. ureae, and also H. influenzae type b from Pasteurellae. The pattern of major sugars in P. ureae and P. haemolytica resembled that of A. actinomycetemcomitans. Major fatty acids of the whole-cell methanolysates provided no basis of interspecies differentiation.

Further characterization of Bacteroides endodontalis, an asaccharolytic black-pigmented Bacteroides species from the oral S cavity

In this study, the isolation, characterization, and identification of Bacteroides endodontalis is described. It was found that this asaccharolytic black-pigmented Bacteroides species is associated with infected dental root canals and oral submucous abscesses. B. endodontalis could be differentiated from B. gingivalis by a negative direct hemagglutination test and the absence of trypsin and N-acetyl-beta-glucosamidase. B. endodontalis could be differentiated from B. asaccharolyticus by the absence of alpha-fucosidase, its inability to grow in an atmosphere of 95% N2-5% H2, and a growth requirement for menadione. Immune serum raised against B. endodontalis strain HG 370T agglutinated only B. endodontalis cells. Precautions for the isolation of B. endodontalis are discussed.

Effect of self-administered daily irrigation with 0.02% SnF2 on periodontal disease activity

To determine the effect on periodontal health of a daily self-administered irrigation with 0.02% stannous fluoride (SnF2) solution, 28 subjects who had moderate to advanced periodontitis were randomly divided into 3 groups: a control group (n = 9) which used no irrigation, a group (n = 8) which used a self-administered water irrigation device (Water Pik) daily with water (H2O group) and a group (n = 11) which used the Water Pik in a similar manner but with SnF2 solution (SnF2 group). All subjects were instructed in routine tooth brushing and flossing but received no other periodontal treatment. 4 study sites were selected from each patient which had pocket depths greater than 4 mm and bleeding upon probing. Plaque index, gingival index, bleeding tendency, pocket depth, loss of attachment, and microbiologic samples of subgingival plaque for morphologic determinations were collected from all study sites at baseline, 2, 6, and 10 weeks. A cross-over was then initiated for 2 additional monthly checks in which the H2O group changed to SnF2 and the SnF2 group was divided into 2 subgroups which either continued to use SnF2 or changed to H2O. The control group completed the study at the beginning of the crossover. The clinical data showed significantly more improvement in periodontal health during the first 10 weeks for the SnF2 group (p less than 0.01). After cross-over, the clinical data indicated the group that changed from H2O to SnF2 significantly improved their periodontal health, while the group that changed from SnF2 to H2O became worse. The microbiologic data showed trends which agreed with the clinical data during the first 10 weeks but were less significant. After cross-over, the %s of motile rods and spirochetes were too small (0-7%) to establish statistically significant changes considering the accuracy of the technique used.

Changes of subgingival total colony forming units and black pigmented bacteroides after a single irrigation of periodontal pockets with 1.64% SnF2

Periodontal pockets of 11 subjects were irrigated once with either 1.64% SnF2 or saline applied by syringe. Changes on the total anaerobic colony forming units (CFU) and black pigmented bacteroides (BPBs) of the irrigated pockets were assessed for 31 days. The results showed little change of the CFUs by either single application of SnF2 or saline. However, SnF2 irrigation produced a decrease in the BPBs for 1 week with the greatest effect (1/2 log reduction) being seen at 3 days after the irrigation. Some subjects had more impressive reductions in BPBs, yet four of the 11 subjects showed no reductions in BPBs in those sites irrigated with SnF2. Further studies with frequent irrigation intervals are necessary to evaluate the potential usefulness of SnF2 for subgingival irrigation.

Microbial ecology of plaque in rats with naturally occurring gingivitis

The microbial ecology of adherent plaque was investigated in relation to the pathological findings of gingivitis in plaque-susceptible rats. Plaque developed in the gingiva of the lower incisor in plaque-susceptible rats, but not in plaque-resistant rats, after they were fed a commercial powder diet. With increase in plaque volume, the total counts of bacteria increased 10(9) to 10(11)/g. In the first 3 months, Bacteroides species increased and became the predominant population. Streptococcus species also increased at the same time. After 9 months, Fusobacterium species and oral Treponema species were recognized in increasing numbers. The anaerobic bacteria increased in proportion with the progression of plaque development. Bacteroides intermedius, Fusobacterium nucleatum, Streptococcus salivarius, and other species were isolated. Acute gingivitis was observed within 3 months, and subacute-chronic gingivitis was observed between 2 and 12 months. These findings suggest that proportional changes in the gingival plaque flora may uniquely contribute to the development of gingival inflammation in this experimental model.

Formation and ecology of plaque at different locations in the mouth

Some recent findings concerning microbial colonization of smooth surfaces of teeth, gingival crevices, occlusal fissures and removable dentures are reviewed considering the many ecologic factors of importance for the oral microbial communities. The oral microbiota is extremely complex comprising at least 200 taxa. In spite of interindividual and site-to-site variations, each oral habitat has a characteristic microbiota ranging from Gram-positive, facultatively anaerobic cocci and rods in occlusal fissures to predominance of Gram-negative, strictly anaerobic rods and spirochetes in deep periodontal pockets.

Subgingival microorganisms and bacterial virulence factors in periodontitis

Considerable information has come forth in recent years on the pathogenic organisms in human periodontitis and the sequence of events by which they produce periodontal disease. Important periodontopathogens include Bacteroides gingivalis, Bacteroides intermedius and Actinobacillus actinomycetemcomitans. Virulence factors of B. gingivalis and B. intermedius may mainly involve enzymes with potential to interfere with host defenses and to disintegrate periodontal tissues. Pathogenic properties of A. actinomycetemcomitans appear predominantly to be exerted by leukotoxin and other noxious products.

Effects of scaling and root planing on subgingival microbial proportions standardized in terms of their naturally occurring distribution

This investigation included a cross-sectional component (284, 20-40-year-old subjects/568 sites) and a longitudinal component (19 subjects with moderate to advanced periodontitis/76 sites). Subgingival plaque samples and clinical data were obtained from all upper second bicuspids and first molars in the longitudinal subjects and from both upper first molars in the cross-sectional subjects. The purpose was to: determine/confirm changes in proportions of selected subgingival microorganisms following root planning combined with conventional oral hygiene procedures in the longitudinal subjects, evaluate those changes in terms of an estimate of the naturally occurring distribution of subgingival microorganisms based on data obtained from the cross-sectional subjects and relate shifts in the subgingival microorganisms to changes in clinical measurements. Changes following treatment at sites with pre-instrumentation probing depths greater than or equal to 4.5 mm included cocci, 18.3 to 46.9%; spirochetes, 20.9 to 3.1%; total motile organisms, 28.5 to 5.9%; Fusobacterium spp., 10.2 to 2.2%; and dark-pigmented Bacteroides spp., 14.0 to 9.7%. Translating proportions of microorganisms in samples from subjects in the longitudinal treatment study to equivalent percentile ranks within the large cross-sectional data base demonstrated that at probing depths greater than or equal to 4.5 mm cocci moved from below the 50th percentile in our estimate of the naturally occurring distribution of subgingival microorganisms to above, and spirochetes, total motile organisms and Fusobacterium spp. moved from above the 50th percentile to below. The microbiological findings were consistent with statistically significant improvements in clinical measurements. Statistically significant changes also occurred in microorganisms at sites with initial probing depths less than 4.5 mm.

Susceptibility of human oral anaerobic bacteria to antibiotics suitable for topical use

17 antibiotics, with potential for topical use, were tested for their activity against the human oral flora. Concentrations (mumol/l) required to inhibit 90% of test strains are presented and drug activities are compared. The total cultivable oral flora was susceptible to the tetracyclines including tetracycline itself, minocycline, doxycycline, and oxytetracycline and to erythromycin. On the other hand, actinobolin, kanamycin, neomycin, streptomycin, spiramycin, tyrothricin, vancomycin, clindamycin, and chloramphenicol were ineffective against many of the human oral anaerobic bacteria even at high concentration. Penicillin was effective at high concentrations but could not be recommended because organisms which are not inhibited by low concentrations are penicillinase producers. Carbenicillin was effective against all organisms except Actinobacillus actinomycetemcomitans. The gram-negative organisms involved in adult periodontitis were most susceptible to the tetracyclines, tyrothricin, carbenicillin and clindamycin, while those associated with localized juvenile periodontitis were susceptible to the tetracyclines or erythromycin. These data, combined with the previous findings that some tetracyclines exhibit marked substantivity and collagenase inhibition activity, indicate that tetracycline or minocycline are likely to be good choices in the treatment or prevention of oral diseases.

Transmission and colonization of Actinobacillus actinomycetemcomitans in localized juvenile periodontitis patients

Actinobacillus actinomycetemcomitans is a Gram-negative oral microorganism, which has been implicated in the etiology of localized juvenile periodontitis and in severe medical infections such as bacterial endocarditis. This study evaluated the ability of periodontal probes to transmit A actinomycetemcomitans from juvenile periodontitis lesions to healthy gingival sulci in the same patient. Localized juvenile periodontitis patients exhibiting first molar and incisor alveolar bone loss and with large numbers of A actinomycetemcomitans in deep periodontal pockets were included in this study. A periodontal probe was inserted into periodontal pockets of 6 mm or greater depth. The probe was then placed into a healthy gingival sulcus of 3 mm or less, in the same subject. Fifty-five transfers by probing were made and A actinomycetemcomitans in both the donor and recipient sites was assessed by a selective culture technique. The results indicate that periodontal probes can become contaminated with A actinomycetemcomitans from juvenile periodontitis lesions during routine dental examinations and can transfer this microorganism from infected to previously uninfected sites. However, A actinomycetemcomitans inoculated into the healthy gingival sulci did not permanently colonize these sites since the organisms were eliminated within 3 weeks.

Lysozyme-mediated aggregation and lysis of the periodontal microorganism Capnocytophaga gingivalis 2010

The ability of lysozyme to aggregate and lyse the gram-negative capnophilic periodontal microorganism Capnocytophaga gingivalis 2010 was monitored optically at 540 nm. Both hen egg white and chromatographically purified human lysozymes had significant but similar aggregation potentials for both logarithmic- and stationary-phase bacteria. In general, an increase in enzyme concentration resulted in a graded increase in both the initial and maximum changes in turbidity which occurred during the reaction period. The greatest change in turbidity occurred within the initial minutes of interaction of lysozyme and the cells, and the extent of aggregation paralleled a rapid depletion of lysozyme by the suspensions during the first minute of its incubation with the bacteria. Interestingly, the muramidase inhibitors N-acetyl-D-glucosamine and histamine did not block aggregation, whereas maleylation of lysozyme completely inhibited its aggregating ability. Demaleylation, however, restored aggregation activity comparable to the native enzyme, indicating that maleylated lysozyme retained its integrity and that aggregation was primarily dependent on charge. The addition of up to physiological concentrations of NaHCO3 and NaCl to cell aggregates resulted in varying degrees of deaggregation and lysis. Surprisingly, ultrastructural analysis of lysozyme-treated cells revealed morphological changes with or without the addition of salt. Damage appeared to occur at the blunted polar end of the cells where there was a large spherical outpouching bordered by a damaged cell envelope. Damaged cells uniformly contained dense granular cytoplasmic debris. In effect, the cationic enzyme lysed C. gingivalis 2010, which was not apparent in the spectrophotometric assay. The paradoxical finding that during bacterial aggregation there was lysis may be of significance to the further elucidation of lysozyme's antibacterial role in the gingival sulcus.

Clinical studies of one family manifesting rapidly progressive, juvenile and prepubertal periodontitis

We report clinical, radiographic and historical data on a large family with an unusually high prevalence of periodontitis. The proband, a 20-year-old black male, had the classic features of juvenile periodontitis (JP). His father was periodontally normal, while his mother had lost all her teeth at age 27 because of rapidly progressive periodontitis (RP). In addition to the 13 living children the couple had had 2 miscarriages. Of the children, one had RP, five had JP and two had prepubertal periodontitis (PP). Both maternal grandparents of the proband had become edentulous at an early age, presumably because of early-onset periodontitis. Four of 10 siblings of the proband's mother had early-onset periodontitis. In contrast, the paternal grandparents did not have early-onset periodontitis nor was periodontitis unusually prevalent in the siblings of the proband's father. The pedigree for this family is consistent with, but does not prove, an X-linked dominant pattern of genetic transmission. The natural history of early-onset periodontitis and the relationship among PP, JP and RP are not understood. The fact that the mother of the proband had RP and she had offspring with RP, JP and PP indicates a close relationship among these diseases and argues in favor of a common underlying mechanism. JP was not preceded by PP in the proband nor his affected 21-year-old brother, but one sister had PP, and at age 15 manifested JP. In her case, the alveolar bone around the deciduous molars had been destroyed, but it regenerated as the permanent premolars erupted.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinobacillus actinomycetemcomitans in human periodontal disease

Recent evidence implicates Actinobacillus actinomycetemcomitans in the etiology of localized juvenile periodontitis. This paper reviews the morphological, biochemical and serological charcteristics of A. actinomycetemcomitans, evidence incriminating it as a periodontopathogen, its importance in human nonoral infections, and virulence factors which may be involved in the pathogenesis of A. actinomycetemcomitans infections. A. actinomycetemcomitans is a non-motile, gram-negative, capnophilic, fermentative coccobacillus which closely resembles several Haemophilus species but which does not require X or V growth factors. The organism has been categorized into 10 biotypes based on the variable fermentation of dextrin, maltose, mannitol, and xylose and into 3 serotypes on the basis of heat stable, cell surface antigens. A. actinomycetemcomitans' primary human ecologic niche is the oral cavity. It is found in dental plaque, in periodontal pockets, and buccal mucosa in up to 36% of the normal population. The organism can apparently seed from these sites to cause severe infections throughout the human body such as brain abscesses and endocarditis. There is a large body of evidence which implicates A. actinomycetemcomitans as an important micro-organism in the etiology of localized juvenile periodontitis including: (1) an increased prevalence of the organism in almost all localized juvenile periodontitis patients and their families compared to other patient groups; (2) the observation that localized juvenile periodontitis patients exhibit elevated antibody levels to A. actinomycetemcomitans in serum, saliva and gingival crevicular fluid; (3) the finding that localized juvenile periodontitis can be successfully treated by eliminating A. actinomycetemcomitans from periodontal pockets; (4) histopathologic investigations showing that A. actinomycetemcomitans invades the gingival connective tissue in localized juvenile periodontitis lesions; (5) the demonstration of several pathogenic products from A. actinomycetemcomitans including factors which may: (a) facilitate its adherence to mucosal surfaces such as capsular polysaccharides; (b) inhibit host defense mechanisms including leukotoxin, a polymorphonuclear leukocyte chemotaxis inhibiting factor, and a lymphocyte suppressing factor (c) cause tissue destruction such as lipopolysaccharide endotoxin, a bone resorption-inducing toxin, acid and alkaline phosphatases, collagenase, a fibroblast inhibiting factor and an epitheliotoxin.(ABSTRACT TRUNCATED AT 400 WORDS)

The role for butyrate and propionate in mediating HeLa-cells growth inhibition by human dental plaque fluid from adult periodontal disease

To determine to what extent propionate and butyrate, secreted in vitro by various oral bacteria, account for the growth-inhibiting activity of plaque fluid in gingivitis in the absence or presence of chronic periodontitis, the fluid phase of plaque from each of these disease forms was obtained by homogenizing the bacteria with 0.13 M NaCl, centrifuging the mixture and Millipore-filter-sterilizing the plaque-fluid-extract supernatant. Toxins were detected and measured by growth inhibition of HeLa cells grown in minimal Eagle medium supplemented with calf serum and antibiotics. Samples of butyrate, propionate or plaque-fluid extract were added and inhibition of growth was determined relative to control cultures. The toxins in each extract were characterized by their stability to heat, freeze-drying and elution on gel filtration. Butyrate and propionate contents were measured with a Hewlett-Packard 5880A gas chromatograph. The plaque-fluid extracts from each group had similar contents of butyrate, but most of the activity was due to heat-sensitive high mol. wt components. Butyrate and propionate accounted for only 5 to 15 per cent of the total activity. High mol. wt exotoxins, rather than butyrate or propionate, were the most prominent and freeze-drying-stable tissue-destructive agents in the plaque fluid from subjects with or without periodontitis.