Subgingival Area Research Articles

Fusobacterium alocis sp. nov. and Fusobacterium sulci sp. nov. from the Human Gingival Sulcus

Two new species, Fusobacterium alocis and Fusobacterium sulci, are described. They were isolated principally from subgingival areas associated with gingivitis or periodontitis. Strains of these species were nonreactive in the biochemical tests usually used and were differentiated most readily from each other and from other Fusobacterium species by patterns of soluble cellular proteins determined by polyacrylamide gel electrophoresis. The type strains of the species are F. alocis ATCC 35896 and F. sulci ATCC 35585.

Gas-liquid chromatography of the gingival fluid as an aid in periodontal diagnosis.

There is increasing evidence that rod‐shaped Gram negative anaerobic bacteria, as those belonging to black‐pigmented Bacteroides, may play a role in the pathogenesis of periodontal diseases. Anaerobic bacteria are known to produce, as end‐products of their metabolism, several volatile fatty acids, whose detection in clinical specimens by direct gas liquid chromatography (GLC) has been usefully utilized to demonstrate their presence in the infected site. The results obtained analyzing by GLC the gingival fluid collected from patients suffering from periodontal diseases are reported here. A good statistical correlation of the GLC profile has been found with the gingival index and the colonization by gram‐negative bacteria at each selected site.The data obtained strongly suggest that butyric acid may be considered a reliable marker of the severity of the disease, and its quantitative changes may be useful in following the clinical course of the process. The data correlate well with the biological activities of butyric acid, which have been reported to be abundant in plaque and to exert a cytotoxic activity on a variety of cells including gingival fibroblasts.No correlation has been found between gingival fluid flow rate and fatty acids profile in GLC. It can be concluded that GLC measures the overall metabolic activity of the bacterial population colonizing the subgingival area, while the rate of gingival fluid flow reflects the degree of the inflammatory response of the host. The combined use of the two laboratory tests should provide the clinician with more quantitative and reproducible parameters for monitoring the disease activity.

Colonization of the Subgingival Area by Bacteroides gingivalis

The initial event in colonization of the subgingival area by B. gingivalis is its attachment to host cells and Gram-positive bacteria in pre-formed plaque. The level of B. gingivalis is partly governed by products of other plaque bacteria, especially by sanguicin. Once B. gingivalis resides in its nidus and starts to proliferate, expulsion of pre-existing residents may occur, especially of attached Gram-positive bacteria, through the inhibitory action of the B. gingivalis product, hematin. The bacteriocin produced by black-pigmented Bacteroides also seems to play an important role in their establishment. Melaninogenicus possessed strong inhibitory activity against Actinomyces species. This was not completely confirmed with fresh isolates of B. gingivalis from advanced periodontitis patients. Various factors other than inhibitory substances produced by B. gingivalis and related bacteria can also affect the colonization of this species. Since the crevice area is influenced by gingival fluid, the nature of specific antibody and the other affecting components should be considered collectively with the interaction between new predominant colonizers and other pre-existing residents.

The periodontal microflora of juvenile diabetics. Culture, immunofluorescence, and serum antibody studies.

These studies demonstrate a unique constellation of organisms populating the subgingival area in periodontitis lesions of patients with juvenile or insulin-dependent diabetes mellitus (IDDM). The cultivable microflora was predominated by Capnocytophaga and anaerobic vibrios in the patients studied. In some patients, Actinobacillus actinomycetemcomitans were also found. This distinguishes the subgingival flora of IDDM patients suffering from periodontitis from that of patients with localized juvenile periodontitis (LJP), and that of adult periodontitis patients. In LJP most patients harbor both A actinomycetemcomitans and Capnocytophaga subgingivally; and in periodontitis lesions from nondiabetic adults, black-pigmented Bacteroides such as B gingivalis or B melaninogenicus subspecies intermedius are often found. Antibiotic susceptibility patterns suggest that penicillin or tetracycline or its analogs such as minocycline may be effective against the predominant cultivable microflora in periodontal lesions of IDDM patients; however, individual patients may harbor flora with significant resistance to these antibiotics.

In vitro cytotoxicity of orthodontic bonding materials

Previous studies have shown that toxic reactions to direct-bonding adhesives can be demonstrated both in animals and in cell culture tests. These effects have also been shown with other related dental materials. The purpose of this study was to compare the relative toxicity of a number of common orthodontic adhesives and to determine, by means of a rapid, sensitive in vitro cell culture agar overlay test, how their toxicity changed with time subsequent to polymerization. Various orthodontic bonding materials were tested either immediately or at various times up to 30 days after polymerization. The cells were stained with a vital dye (neutral red), the diameter of the area of unstained, nonviable cells was measured, and the results of three tests per sample were averaged and analyzed by means of Duncan's Multiple Range Tests. All materials were found to have some cytotoxic effect immediately after mixing, with the activator components of two “no-mix” materials exhibiting significantly higher toxicity (p < 0.05) than other materials tested. The sealant materials showed a significantly greater toxicity than paste resins, both initially after mixing and after 30 days postpolymerization. If applicable to the clinical situation, these data indicate that care is needed particularly in handling liquid activators. Excess “polymerized” sealant, which may contain many nonreacted groups, should be carefully removed by scaling peripheral to the bracket bases, particularly in subgingival and interproximal areas.

Degradation of immunoglobulins A2, A2, and G by suspected principal periodontal pathogens.

Attention has recently been focused on immunoglobulin A1 (IgA1) protease production as a possible virulence factor of bacteria implicated in meningitis and gonorrhea. This report demonstrates that suspected principal etiological agents in destructive periodontal disease include bacteria capable of degrading IgA1, IgA2, and IgG. Representative strains of Bacteroides melaninogenicus subsp. melaninogenicus and Capnocytophaga cleaved IgA1 but not IgA2 in the hinge region to yield intact Fab and Fc fragments. All Capnocytophaga strains also cleaved IgG in the same way. The majority of strains of Bacteroides asaccharolyticus and B. melaninogenicus subsp. intermedius caused complete degradation of both IgA1 and polyclonal IgG. However, some strains left the Fc part of IgA1 intact. Several strains were also capable of completely decomposing IgA2 and S-IgA. Significant IgA-cleaving enzyme activity was detected in whole subgingival dental plaque collected from patients with destructive periodontal disease. The results indicate that colonization of the subgingival area by B. asaccharolyticus, B. melaninogenicus, and Capnocytophaga spp. can induce a local paralysis of the immune defence mechanisms, thereby facilitating the penetration and spread of potentially toxic substances, lytic enzymes, and antigens released by the entire subgingival microflora.

Actinobacillus actinomycetemcomitans in human periodontal disease: a cross-sectional microbiological investigation.

Actinobacillus actinomycetemcomitans is a facultative gram-negative bacterium which has been associated with severe oral and nonoral infections. This study examined its occurrence in the oral cavities of 10 normal juveniles, 11 normal adults, 10 juvenile periodontitis patients, and 12 adult periodontitis patients. Four deep periodontal pockets and two normal periodontal sites were sampled in the diseased patients, and six normal periodontal sites were sampled in the healthy individuals. In all subjects samples were obtained from the cheek, tongue, and saliva. Samples from a total of 172 normal periodontal sites, 83 deep periodontal pockets, 42 cheek mucosae, 42 tongue dorsa, and 42 salivas were examined. Isolation was performed by using a medium for selective isolation of A. actinomycetemcomitans (Trypticase soy agar [BBL Microbiology Systems] supplemented with 10% serum and 75 mug of bacitracin per ml). The carrier rates were 20% for normal juveniles, 36% for normal adults, 50% for adult periodontitis patients, and 90% for juvenile periodontitis patients. A. actinomycetemcomitans was on average recovered in about fivefold-higher numbers from infected deep periodontal pockets than from infected normal subgingival areas. Samples of periodontal pockets generally contained 100-fold-more cells of A. actinomycetemcomitans than did samples of the cheek, tongue, and saliva. A. actinomycetemcomitans is commonly isolated from patients with juvenile periodontitis, often isolated from patients with adult periodontitis, and occasionally isolated from normal juveniles and adults. Its primary oral ecological niche appears to be dental plaque and periodontal pockets.

Descriptions of Eubacterium timidum sp. nov., Eubacterium brachy sp. nov., and Eubacterium nodatum sp. nov. Isolated from Human Periodontitis

Three new species of Eubacterium, E. timidum, E. brachy, and E. nodatum, which were isolated principally from subgingival areas associated with periodontitis, are described. All are anaerobic, gram-positive, non-saccharolytic rods. They are differentiated from each other and from other non-saccharolytic species of eubacteria by acid and gas products in broth cultures and by morphological and growth characteristics. The type strains for the species are as follows: E. timidum ATCC 33093; E. brachy, ATCC 33089; and E. nodatum, ATCC 33099. These species were detected in 35 to 42% of the subgingival samples examined and, where present, constituted 3 to 57% of the cultivable flora. Strains of these species were isolated only occasionally from the adjacent supragingival areas sampled.

Studies in plaque pathogenicity. I. Plaque collection and limulus lysate screening of adherent and loosely adherent plaque.

A study was undertaken to assay and compare the pathological potential of loosely adherent plaque (LAP) with that of adherent plaque (AP) using the limulus lysate assay (LLA). A technique was devised for collection both AP And LAP from supra‐ as well as subgingival tooth areas under pyrogen‐free conditions. Five supragingival samples (AP &amp; LAP) were collected from teeth (G.I.= &lt; 1) after subjects had abstained from tooth cleaning for two weeks. Five subgingival samples were collected from mylar strips one week after placement in periodontal pockets not less than 4 mm and not more than 7 mm in depth. All samples were lyophilized, recontituted and analyzed for plaque mass by the quantitative ninhydrin reaction (Moore and Stein, 1954). Samples were analyzed for limulus lysate activity by a modification of the LLA of Levin and Bang (1964).Results from the five supragingival samples indicate that plaque mass, as determined by the ninhydrin reaction, was 4–5 fold greater in AP than in LAP. In the five subgingival samples, ninhydrin values for AP were two times higher than LAP. In spite of these differences in plaque mass, limulus activity in all LAP samples was consistently higher than in comparable AP samples when expressed as limulus activity per mole of amino acid. These preliminary findings suggest that subgingival LAP, situated in a position of strategic importance, is biologically active and deserves further study.

Gingival reaction to well-fitted subgingival proximal gold inlays.

Abstract Proximal inlays were seated in contralateral teeth in eight subjects with clinically healthy gingivae. After 23 days, the subgingival area and part of the supragingival surface of one of the inlays was roughened with an abrasive instrument up to 1 mm above the gingival margin; the other inlay remained polished. Gingival fluid flow rate was buccally and lingually measured in the papillary area close to the proximal roughened and polished inlay surfaces and also at papillae beside sound proximal surfaces of the same teeth during a period of 85 days. In addition, plaque was scored and also assessed planimetrically.The mean gingival fluid flow rate was significantly higher adjacent to both the rough and polished filling surfaces when compared with proximal surfaces without restoration. Plaque indices were similar in the vicinity of filled and sound proximal areas irrespective of the gold surface texture. Planimetrically more plaque was formed on the sites of roughened inlays.

Bacteriologic studies of periodontal pockets ten minutes after curettage.

IN A PREVIOUS STUDY 1 samples of supra and subgingival microbial populations taken from mylar strips on subjects with treated periodontal pockets revealed that vibrios and fusobacteria were statistically more abundant over a period of 2 to 49 days in subgingival areas. In addition, a complex flora was established as early as two days in both supra and subgingival areas. The present study is an effort to characterize the very early stages of plaque accumulation by examining those microorganisms which attach to mylar strips subgingivally after ten minutes.

The relation of new knowledge of the gingiva to crown and bridge procedures

Certain recent research on the gingiva that has a practical application to crown and bridge prosthesis is presented. The investigations discussed provide a concept which endows the free gingiva with physiologic attributes common to mucous membranes found elsewhere in the human body. These attributes are manifested by the ability of the gingiva to remove injurious agents from the subgingival areas, by its ability to repair injured and lost parts following operative trauma or infection, and by its ability to heal physiologic readaptation of the new gingival tissue to the tooth surfaces following complete removal of all injurious agents. This biologic concept supports accepted clinical practices and provides the practitioner with basic scientific guides to successful treatment.