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Query: UMLS:C0031099 (periodontitis)
 12,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Polymorphonuclear leukocytes (PMNs) have been implicated in the pathogenesis of inflammatory gingivitis and periodontitis. To further study the role of PMNs in mediating gingival injury, we cocultured these cells in vitro with monolayers of human gingival epithelial cells. Scanning electron microscopy revealed that the epithelial cells were homogeneous and SDS-PAGE/immunoblot analysis identified the presence of keratins K3, K13 and the K6/16 pair which authenticated the oral origin of the cells. Injury to the gingival cells was determined by scanning electron microscopy and measurement of cell detachment and cytolysis. Unstimulated PMNs produced minimal lysis or detachment, but PMNs stimulated by phorbol myristate acetate produced marked epithelial cell detachment without lysis, which was time- and PMN-dose-dependent. Supernatants of activated PMNs were similarly effective, indicating that the mediator was a stable soluble substance. Elastase and cathepsin G, two neutral proteases of PMN origin, produced time- and concentration-dependent detachment of gingival epithelial cells, suggesting that these enzymes may mediate this form of injury. In other studies, gingival epithelial cells were exposed to PMN myeloperoxidase (MPO), chloride and glucose plus glucose oxidase (GO) as a hydrogen peroxide (H2O2) generating system. The toxic oxygen species produced by this system caused lysis of the epithelial targets which was dependent on the duration of incubation and the concentrations of MPO and GO. Azide, an inhibitor of MPO, and catalase, a scavenger of H2O2, inhibited the lytic activity of this system. Scanning electron micrographs of gingival epithelial cells cocultured with activated PMNs showed lifting of the cells from the plating surface, while target cells attacked by the MPO system revealed extensive damage of cell membranes. These studies indicate that activated PMNs cause nonlytic detachment injury to gingival epithelial cells which may be mediated by digestion of their extracellular matrix by granule neutral proteases. Furthermore, PMN MPO is capable of generating toxic oxygen species which can lyse these epithelial cells. Collectively, these actions could have profound adverse effects on the function and integrity of the gingival epithelium.
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PMID:Neutrophil-mediated damage to human gingival epithelial cells. 131 Oct 41

Gingival crevice and periodontal pocket pH, measured directly with glass micro-electrodes, was near neutral at most sites in most individuals (mean pH 6.92 +/- 0.03 SEM, 69 subjects). Periodontal state ranged from healthy to periodontitis but neither clinical evidence of gingivitis at a site nor pocket depth were associated with crevicular pH different from that at healthy sites. This finding contradicts earlier reports that gingivitis is associated with a crevicular pH as alkaline as pH 9.06. Metallic antimony electrodes as used by earlier investigators were found to give pH readings that were too high by as much as 1.5 pH units in the presence of organic reducing agents of the type produced by oral bacteria within gingival crevices. In contrast, glass micro-electrodes respond only to hydrogen ions and thereby provided accurate measurements of pH even in the presence of organic reducing agents. Loss of CO2 to the atmosphere from biological fluids that are bicarbonate buffered resulted in a shift to alkaline pH by as much as 1 pH unit. As a result, only measurements taken within gingival crevices or periodontal pockets can provide accurate measurements of crevice or pocket pH.
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PMID:The pH of gingival crevices and periodontal pockets in children, teenagers and adults. 190 71

The identification of plaque as the etiological agent in chronic gingivitis and the progression of chronic periodontitis, has intensified the search for effective chemical antiplaque agents to aid in the prevention and treatment of these diseases. To date, no ideal compound has been identified. Using the experimental gingivitis model, the effectiveness of a 1.5% hydrogen peroxide-containing oral rinse, applied as a conventional mouthrinse and in an oral irrigation device, was evaluated. The ability of the mouthrinse to inhibit the development of plaque and gingivitis in the two experimental groups, was compared with controls using a placebo rinse over two 7-day periods. At no time was there any statistical difference between either of the experimental groups and/or the placebo group in terms of gingival or plaque scores. This study concluded that a 1.5% hydrogen peroxide mouthwash was of no therapeutic value in the prevention or treatment of an experimental gingivitis, when used as a mouthrinse or in an oral irrigator.
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PMID:Hydrogen peroxide, the effect on plaque and gingivitis when used in an oral irrigator. 209 12

The purpose of this study was to examine and evaluate the short-term (six months) effects of clinical trials of nonsurgical periodontal therapy. The subjects studied included consisted of 34 patients, 24-52 years of age (836 teeth), with various degrees of advanced periodontitis. Following a baseline examination which included assessments of the gingival index (GI), plaque index (PlI), calculus index (CI), probing depth, and attachment level, the patients were subjected to nonsurgical therapy. Differences between various treatment intervals for the pockets initially measuring 1-3 mm, 4-6 mm, and 7 mm or more were analyzed by using the paired Students t-test. Following meticulous debridement of periodontal pockets with ultrasonic instrumentation, routine pocket irrigation with hydrogen peroxide (2.5-3.0%) and chlorhexidine gluconate solutions (0.12%) was performed by the authors as well as by the patients at sites with moderate to deep pockets and furcation involvement. Furthermore, the patients were supervised under a maintenance care program which provided patient motivation, the teaching of oral hygiene procedures, and offered regular recall for six months. The results demonstrated that non-surgical therapy resulted in a prominent reduction of gingival inflammation, dental plaque and calculus formation, and finally increased gingival recession. Also, for sites with an initial probing depth of 1-3 mm, there was a slight loss (0.1 mm) of the attachment level, 3 and 6 months after therapy. For sites with an initial probing depth of 4-6 mm, there was some attachment gain (0.31 mm and 0.69 mm) at 3 and 6 month post-treatment intervals. For pockets 7 mm or more in depth, a pronounced gain (0.49 mm and 1.00 mm) of attachment was noted following 3 and 6 month intervals. Generally, an obvious reduction of probing depth was constantly observed after nonsurgical treatment in each of the three initial pocket groups mentioned above. The changes of probing depths between baseline and at 3 or 6 months after treatment were 0.17 and 0.23, 1.23 and 1.75, and 1.83 and 2.63 mm, respectively. With the exception of attachment loss for the pockets initially measuring 1-3 mm, the difference of GI, PlI, CI, probing depth, and attachment level between baseline and 3 or 6 months after treatment were found statistically significant in each of the three initial pocket groups when analyzed individually by ANOVA.
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PMID:Clinical observations of the effects of nonsurgical periodontal therapy on human periodontal disease. II. Ultrasonic scaling and root planing for 6 months. 265 13

Since they are found to be increased in lesions of acute necrotic ulcerative gingivitis or marginal periodontitis, agents for these diseases. In the present study, 38 pure cultured strains were obtained as a result of isolation and culture of samples collected from lesions of marginal periodontitis (periodontal pokets), and the biological and biochemical characteristics of these strains were investigated. 1) Light microscopy (including dark-field microscopy) and transmission electron microscopy (negative staining) were used for observation of the morphology and cellular structure of the strains. The cells had a spiral shape, and showed active movement. Based on the above findings the cultured strains were all confirmed to be spirochetes of small to medium size, being 0.08-0.24 micron in width. 2) Growth and motility of the strains were investigated on various types of culture medium. Intense growth and movement were noted in strains cultured in bovine liver exudate medium containing horse serum (pH 7.2) at 37 degrees C under anaerobic conditions produced by the evacuation-replacement method (95% N2, 5% CO2) for 3-7 days after inoculation. 3) Thirty-five strains were positive for indole production and decomposition of urea, mucin, hippuric acid and esculin. Production of hydrogen sulfied was observed in 31 strains. In decomposition tests for 17 carbohydrates, 17 strains were positive for galactose and 14 strains were positive for glucose, while 11 strains were positive for dextrin and 10 strains for fructose upon decomposition of soluble starch. Other carbohydrates were also decomposed by a few strains. 4) In an investigation of the production of alcohol and lower fatty acids, among the metabolic products detected by gas chromatography, a large amount of acetic acid and small amounts of ethanol, lactic acid, propionic acid, pyruvic acid were observed. 5) The results of enzyme activity tests using an API ZYM system indicated relatively high activities of esterase, esterase-lipase, alpha-glucosidase, alkaline phosphatase, trypsin and acid phosphatase.
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PMID:[Biological and biochemical characteristics of the oral spirochetes isolated from the focus of marginal periodontitis]. 276 48

The effects of repeated subgingival irrigation on Actinobacillus actinomycetemcomitans was examined. 24 periodontal pockets harboring A. actinomycetemcomitans in 3 juvenile and 4 adult periodontitis patients were studied. The protocol included bi-weekly subgingival irrigation with hydrogen peroxide of the periodontal sites until the micro-organism was no longer detected by selective culture, or for 6 months. A. actinomycetemcomitans was gradually suppressed to below detection following the irrigation regime and could no longer be detected in 46% of the sites at completion of the irrigation protocol. The sites were microbiologically re-examined 5 months after cessation of the irrigation regime. A. actinomycetemcomitans re-occurred in only 2 of the sites from which it had originally been suppressed below detection. The results indicate: (1) that the irrigation regime tested has some potential to suppress A. actinomycetemcomitans in periodontal pockets; (2) that the effect of the irrigation protocol generally lasted for 5 months; (3) that the reduction rate of A. actinomycetemcomitans to below detectable levels seems related to the initial number of cultivable bacteria from the periodontal pocket.
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PMID:Effects of subgingival irrigation on A. actinomycetemcomitans. 292 71

The purposes of this 2-year longitudinal study were to: compare the clinical effectiveness of patient applied sodium bicarbonate, hydrogen peroxide, and sodium chloride (S/P) to the use of conventional oral hygiene methods and to investigate the motivational effect of using phase-contrast microscopy in teaching effective oral hygiene. Initially, 972 subjects were screened for signs of periodontitis. From these, 347 with early to moderate periodontitis were selected and each was randomly assigned to one of four home treatment regimens after scaling and root planing. The four treatment regimens included: conventional oral hygiene procedures, conventional oral hygiene procedures plus phase-contrast demonstration of subgingival microbial forms for oral hygiene motivation, S/P oral hygiene, and S/P oral hygiene plus phase-contrast demonstration of subgingival microbial forms for oral hygiene motivation. Plaque, bleeding, gingival inflammation, probing depth, and clinical attachment level were recorded at baseline, 8, 16, and 24 months. Subjects were recalled for reinforcement of oral hygiene and periodontal prophylaxis at various intervals. Data were analyzed based on disease severity, location of index sites and compliance. The results indicated that both conventional oral hygiene procedures and the S/P regimen were effective in reducing clinical signs of disease when combined with professional care. There were no differences between the two regimens in clinical effectiveness and trends favoring microscopic viewing of subgingival plaque for motivational purposes were not statistically significant.
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PMID:Salt and peroxide compared with conventional oral hygiene. I. Clinical results. 303 64

The existence of antagonistic and commensal relationships between microorganisms was investigated. The predominant cultivable flora in 172 plaque samples from active and non-active sites in 32 human subjects with destructive periodontitis was determined. The presence of putative periodontopathic organisms (Bacteroides gingivalis, Bacteroides intermedius, Bacteroides forsythus, Wolinella recta, Actinobacillus actinomycetemcomitans, and Eikenella corrodens) in a site was correlated with the absence of certain viridans streptococci (Streptococcus sanguis, Streptococcus uberis and Streptococcus intermedius), and vice versa. A strong commensal relationship was found between B. gingivalis and Strep. intermedius. The second study involved 3 subjects with intractable periodontitis whose plaque harboured large numbers of one or more of these periodontopathic organisms. This plaque contained fewer organisms capable of inhibiting the growth of the periodontopathic strains in vitro when compared with a clinically-healthy control subject. Intermediate levels of inhibitors were found in plaque taken from non-active lesions. The majority of inhibitors in plaque from the healthy control were viridans streptococci. Hydrogen-peroxide production by these organisms appears to be the principal mechanism of growth inhibition for periodontopathic organisms. Bacterial interactions may thus be causally related to both periodontal health and disease.
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PMID:The relationships between streptococcal species and periodontopathic bacteria in human dental plaque. 386 68

Spirochetes have been implicated in the pathogenesis of several human infections including syphilis, yaws, Lyme disease, and periodontal diseases. We examined soluble sonic extracts of oral spirochetes (Treponema denticola and T. vincentii) for their ability to alter human lymphocyte function. These organisms were isolated from subgingival plaque of patients with periodontitis. We found that sonicates of several but not all strains of T. denticola caused a dose-dependent inhibition of human lymphocyte responsiveness to Con A, PHA, PWM, and the recall antigen SKSD. Suppression involved alterations in DNA, RNA, and protein synthesis; there was no effect on cell viability. In contrast, sonicates of T. vincentii (medium-sized spirochetes) had no demonstrable effects on lymphocyte activation. The suppressive factor derived from T. denticola is heat-labile with a m.w. of approximately 100,000. To achieve maximal suppression, sonicates had to be added during the first 24 hr of incubation; there was no inhibition observed when added at 48 or 72 hr (along with 3H-TdR). Suppression was dependent on the presence of adherent monocytes; removal of these cells prevented spirochete-induced suppression of lymphocyte proliferation. Furthermore, the combination of indomethacin and catalase were able to reverse (or prevent) the inhibitory effects of the spirochete extracts, demonstrating a requirement for both prostaglandins and hydrogen peroxide. The potential role of such suppressive factors in periodontal disease is discussed.
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PMID:Suppression of human lymphocyte responses by oral spirochetes: a monocyte-dependent phenomenon. 669 6

Gram-negative, non-saccharolytic, brown- or black-pigment-forming, nonmotile anaerboic coccobacilli, capable of decomposing hydrogen peroxide and identified as Bacteroides asaccharolyticus (B. melaninogenicus subsp. asaccharolyticus), were isolated from the supra- and subgingival plaques of beagle dogs with gingivitis or periodontitis. The organisms remained viable for many hours in an aerobic atmosphere as evidenced by their ability to grow subsequently in an anaerobic environment. They also grew well on agar media that were not reduced before use. Although blood was required for pigmentation of colonies, organisms grew on media that lacked hemin, menadione, blood, or reducing compounds. Increased oxygen tolerance, catalase activity, and different nutritional requirements differentiate these organisms from strains of B. asaccharolyticus isolated from humans.
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PMID:Characteristics of Bacteroides asaccharolyticus from dental plaques of beagle dogs. 738 Oct 20


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