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Biomedical subjects

W B Clark

Publications and source records attributed to W B Clark.

At least 55 records · Page 3Linked to original sources
PubMed1991

Relationship between gingival inflammation and painfulness of periodontal probing.

The relationship of gingival inflammation to the pain associated with periodontal probing was assessed at baseline (B), and 1 month (1M) and 3 months (3M) later in 46 subjects. At each of the 3 sessions, clinical measures of gingival inflammation included an observational gingival index and bleeding score. In addition, periodontal probings of all existing teeth was performed with a constant force probe (25 g). Following completion of the probing at each session, subjects rated the global painfulness of the probing using a visual analog scale for pain. Results of this study showed that judged painfulness of probing was related to clinical inflammation (bleeding score) at baseline and 1 month and suggest that the degree of periodontal inflammation is related to the pain and discomfort associated with periodontal probing.

Adult↗
PubMed1991

Subgingival microbiota in squirrel monkeys with naturally occurring periodontal diseases.

The squirrel monkey (Saimiri sciureus) has been proposed as an in vivo model for the study of subgingival colonization by suspected periodontopathogens, such as black-pigmented porphyromonads and prevotellas (BP/P). However, the indigenous microbiota of the squirrel monkey has not been well described. Therefore, in order to more fully characterize the oral microbiota of these animals, we studied two groups of squirrel monkeys from widely different sources. Group I consisted of 50 breeding colony monkeys ranging in age from 9 months to over 6 years which had been raised in captivity; group II consisted of 16 young sexually mature monkeys recently captured in the wild in Guyana. Group I animals in captivity had developed moderate to severe gingivitis, with a mean gingival index (GI) of 2.6; 52% of the sites bled, 26% had detectable calculus, and 83% had detectable BP/P. A group I subset (six animals), for which predominant cultivable microbiota was described, had a mean GI of 2.4. Colony morphology enumeration revealed that five of the six subset animals were detectably colonized with BP/P (range, 0 to 16.9%) and Actinobacillus actinomycetemcomitans (range, 0 to 3.9%); all subset animals were colonized with Fusobacterium species (range, 0.8 to 3.6%), Actinomyces species (range, 2.3 to 11%), and gram-positive cocci (range, 1.4 to 21.4%). Predominant cultivable microbiota results revealed the presence of many bacterial species commonly found in the human gingival sulcus. At baseline, group II animals were clinically healthy and had a mean GI of 1.4; 67% of the sites bled and 2.1% had calculus, and none of the animals had detectable BP/P. Neisseriae were very common in noninflamed sites. Subsequently, when inflamed sites were compared with noninflamed sites in group II animals after they had been maintained in captivity for 6 months, inflamed sites exhibited a more complex microbiota and increased proportions of gram-negative rods and asaccharolytic bacteria.

Animals↗
PubMed1991

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.

Animals↗
PubMed1991

Genetic control of serum antibody responses of inbred mice to type 1 and type 2 fimbriae from Actinomyces viscosus T14V.

Antibodies reactive with type 1 and type 2 fimbriae from Actinomyces viscosus T14V specifically inhibit the adherence of A. viscosus T14V to salivary pellicle-coated tooth surfaces and other bacteria, and these antibodies are thought to modulate colonization by this microorganism. These studies were done to determine whether previously noted differences in the antibody responses of inbred mice to type 1 and type 2 fimbriae might be under genetic control. The serum immunoglobulin G (IgG) and IgM antibody responses of inbred, F1 hybrid, and H-2 congenic mice, immunized with A. viscosus T14V cells, were analyzed by enzyme-linked immunosorbent assays for antibodies reactive with A. viscosus T14V whole-cell type 1 and type 2 fimbriae. The results confirmed earlier findings and indicated striking variations in the amounts of IgG anti-type 1 (23-fold) and anti-type 2 (48-fold) fimbria antibodies elicited. The responses of the 17 inbred strains tested showed a relatively continuous distribution from high to low, as well as marked differences in the responses of H-2 and Igh-C identical strain pairs. An analysis of the responses of F1 hybrid and H-2 congenic mice indicated dominance of the low-responder gene(s) and control by H-2-linked genes. Antisera from two high-responder strains inhibited in vitro bacterial adherence to a much greater degree than antisera from a low-responding strain. These data suggest polygenic control of the magnitude of the IgG anti-type 1 and anti-type 2 fimbria antibody responses by H-2-linked genes as well as background genes not associated with H-2 or Igh-C loci.

Actinomyces↗
PubMed1991

Host responses in the etiology and pathogenesis of periodontal disease.

Periodontal disease is an inflammatory condition of the supporting structures of teeth. This condition is actually considered to be caused by a number of different diseases, possibly associated with different etiologies, rather than a single disease. Due to limitations in our present understanding of cellular and molecular events involved in the pathogenesis of various periodontal diseases, many therapeutic failures still occur. For this reason, studies concerning the responses of the host to pathogenic bacteria are thought to be critically important. This review presents current opinions on the role of host responses in periodontal disease.

Antibody Formation↗
PubMed1990

Myospherulosis of the mastoid antrum: a case report.

Myospherulosis is a recently discovered iatrogenic disease caused by the implantation during surgery of mineral oil- or petrolatum-based products into various tissues. The condition results from the action of lipid substances on extravasated erythrocytes. The case report presented is the first detailed description of this uncommon, unique inflammatory lesion occurring in the mastoid and is the second otitic case reported in the literature. The lesion mimicked recurrent cholesteatoma 6 years following an intact canal wall mastoidectomy. As in myospherulosis of the paranasal sinuses, the symptoms and findings of otitic myospherulosis are those of the preceding disease.

Bacitracin↗
PubMed1990

Binding of colloidal gold-labeled salivary proline-rich proteins to Actinomyces viscosus type 1 fimbriae.

Salivary proline-rich proteins (PRPs), which were purified from parotid saliva, were adsorbed onto 15-nm-diameter gold particles to visualize specific binding of the salivary molecules to Actinomyces viscosus type 1 fimbriae. Negatively stained preparations incubated with PRP-gold conjugates but not bovine serum albumin-gold complexes bound specifically to bacteria possessing type 1 fimbriae, A. viscosus T14V-J1 and 5519. Binding of the PRP-gold probes to strains deficient in type 1 fimbriae, i.e., strains 5951 (type 2 fimbriae only) and 147 (no fimbriae), was negligible.

Actinomyces↗
PubMed1989

Surface appendages, hemagglutination, and adherence to human epithelial cells of Bacteroides intermedius.

Four types of morphologically distinct surface appendages were found on oral strains of Bacteroides intermedius. These appendages, designated as A, B, C, and D, were different in size, with diameters of 1-2 nm, 12 nm, 8 nm, and 5 nm, respectively. Twenty different strains were examined by electron microscopy and 5 strains, 5, 17, 27, 113, and 25611, were selected to be representative of the different appendages encountered. Type A appendages were thin filaments peritrichously arranged on the cell surface and were associated mainly with Strains 5, 113, and ATCC 25611. Type B appendages were present on all 5 strains but these structures were scarce (i.e., less than or equal to 3 per organism). Type C appendages were associated exclusively with Strain 17. Type D appendages were present mainly on Strain 27. Hemagglutination activity of these organisms and their ability to adhere to human buccal epithelial cells were also tested. Strain 17, which possessed Type C appendage (uncommon to the other strains), agglutinated strongly with 5 different species of erythrocytes and adhered avidly to human buccal epithelial cells. The other strains, possessing different types of appendages, showed considerable variation in hemagglutination activity and adherence properties. Correlation between these surface appendages and adherent functions was speculated.

Animals↗
PubMed1989

Efficacy of Perimed antibacterial system on established gingivitis. (I). Clinical results.

A 6-month, double-blind controlled study was conducted on 101 subjects to determine the effect of Perimed antibacterial system, containing povidone-iodine (PVP-I) and hydrogen peroxide (H2O2), on established gingivitis. Subjects were randomly assigned to one of 4 treatment groups: PVP-I/H2O2, PVP-I/H2O, H2O2/H2O or H2O. Gingivitis was assessed by the papillary bleeding score (PBS) and plaque by a modified Quigley-Hein plaque index (PI) at baseline, 3, 12 and 24 weeks. The average baseline PBS and PI for the 4 groups ranged from 2.16-2.31 and 2.87-2.90, respectively. After baseline evaluation, subjects received a supra-gingival scaling and a subgingival irrigation with their respective rinse. Daily rinses were supervised and subgingival irrigation was repeated every 3 weeks. Duncan's multiple range test determined which groups differed from each other. The mean PI at 24 weeks was lower than at baseline in all groups. PVP-I had the lowest PI at all time points. The mean PBS at 24 weeks was 1.48 for PVP-I, 1.62 for H2O2, 1.88 for H2O and 1.34 for PVP-I/H2O2, a reduction from baseline of 31%, 27%, 18%, and 38% respectively. The difference between the PBS for PVP-I/H2O2 and H2O control was significant at each evaluation. There was a 70% reduction in sites with PBS greater than or equal to 3 for PVP-I/H2O2 between baseline and 24 weeks compared to a 34% decrease in the H2O group. It was concluded that the use of Perimed could be a beneficial adjunctive treatment for the prevention and control of gingivitis when used with routine oral hygiene procedures.

Adolescent↗
PubMed1989

Effect of non-surgical periodontal therapy combined with adjunctive antibiotics in subjects with "refractory" periodontal disease. (I). Clinical results.

The aim of the present study was to evaluate the clinical effect of non-surgical periodontal therapy with the adjunct of a selected antibiotic in subjects with refractory periodontitis. 10 subjects were selected for the study; all had a history of periodontal surgery, tetracycline therapy, and regular maintenance by a periodontist. Clinical registrations including gingival index, plaque index, presence of bleeding and suppuration, pocket depth, and duplicate measurements of attachment level were performed at baseline and at monthly intervals. When disease activity was detected based on the tolerance method, a bacterial sample was taken from the active site and its susceptibilities to a number of antibiotics were determined. For the selected 10 subjects, Augmentin was the antibiotic of choice. Each subject received 750 mg/day for 2 weeks, during which time a full-month scaling and root planing was performed under local anesthesia. Clinical re-evaluation was performed after 3, 6, 9 and 12 months. At the time disease activity was detected, the average loss of attachment at all active sites was 2.2 mm, and the increase in pocket depth 1.5 mm. At 3 months post-therapy, these sites had regained 2 mm of attachment which remained stable through the 12-month examination. Pocket depths decreased 2.5 mm over the first 6 months and then stabilized. The frequency of all sites that gained 1 mm or more of attachment increased by approximately 10% over the first 9 months following therapy. The frequency of all sites that decreased 1 mm or more in pocket depth increased approximately 15% over the same period.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Pellicle receptors for Actinomyces viscosus type 1 fimbriae in vitro.

Actinomyces viscosus T14V-J1 and its fimbria-deficient mutant strain possessing type 1 fimbriae strongly aggregated with latex beads treated with acidic proline-rich protein 1, basic proline-rich proteins, and proline-rich glycoprotein and its deglycosylated derivative. These type 1+ strains did not aggregate with latex beads treated with other proteins, such as salivary amylase, salivary histidine-rich polypeptides, laminin, type 1 collagen, fibronectin, or C1q. The type 1+ strains also adsorbed well to experimental pellicles formed with acidic proline-rich protein 1, basic proline-rich proteins, and proline-rich glycoprotein and its deglycosylated derivative on hydroxyapatite (HA) surfaces. These interactions were inhibited with immunoglobulins and Fabs specific for type 1 fimbriae. Type 1- actinomyces exhibited feeble adsorption to latex beads or HA treated with any of the aforementioned proteins. Collectively, these data indicate that actinomyces type 1 fimbriae may specifically interact with several proline-rich salivary molecules, forming experimental pellicles on HA or polystyrene surfaces.

Actinomyces↗
PubMed1989

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.

Animals↗
PubMed1988

Description and clinical evaluation of a new computerized periodontal probe--the Florida probe.

A new periodontal probing system has been developed which incorporates the advantages of constant probing force, precise electronic measurement to 0.1 mm and computer storage of the data. The system includes a probe handpiece, displacement transducer with digital readout, foot switch, computer interface and personal computer. A unique movable arm design enables the probe handpiece to maintain smooth operation and makes it easy to clean and sterilize. Electronic recording of the data (actuated by pressing a foot switch) eliminates errors which occur when probe tip markings are read visually and the data are called to an assistant. Computer storage and analysis of the data facilitates detecting changes in pocket depth and attachment level by rapidly comparing data recorded at different visits. The system was evaluated in 3 experiments using a 0.4 mm diameter tip and a 25 g probing force. The standard deviation of repeated pocket depth measurement was less (0.58 mm versus 0.82 mm) than that of a common probe. With paired readings referenced to an occlusal stent, the standard deviation of repeated attachment level measurements was 0.28 mm. A loss of attachment level was detected to a certainty of 99% with less than a 1 mm change. This is a significant improvement over common probes, which require a 2-3 mm change for equivalent positive identification of change in attachment level.

Computers↗
PubMed1988

Correlation between electronic and visual readings of pocket depths with a newly developed constant force probe.

The purpose of this study was to compare probing measurements obtained using a newly developed constant force electronic probe, which eliminates errors of visual reading and variable force, to those obtained using a standard periodontal probe. The probe was connected to a digital readout through a linear variable differential transformer; the digital readout was connected to a printer and a foot switch. When the probe was in position and the foot switch depressed, the pocket depth was printed to the nearest 0.1 mm. 12 subjects with minimal to early periodontitis were selected for the study. The pocket depths of each patient were recorded electronically utilizing a constant force of 25 g, and conventionally using the same instrument in a "locked" position and visual reading. Probings were performed on each subject by 3 different examiners, on 3 separate occasions 2-3 days apart. The results showed a high correlation between manual and electronic probing. The average correlations for the 3 investigators between examinations were consistently higher for the electronic probings. In comparing the 3 examiners to each other, consistently higher correlations were found for the electronic pocket readings. Correlations for single-rooted teeth were lower for all 3 examiners. The pocket depth measurements recorded when using the manual probe with visual readings were consistently deeper than those obtained using the electronic probe with computer readings. It was concluded that the reproducibility of measurements obtained with the electronic probe was significantly superior to that obtained with a manual probe.

Adult↗
PubMed1988

Attachment level measurements with a constant force electronic probe.

The purpose of the present investigation was to evaluate the reproducibility of probing attachment level measurements using a newly developed constant force electronic probe. The probing force was preset at 25 g (probe diameter 0.4 mm) and was connected to a computer through a variable differential transformer. The measurements were performed on 10 patients with minimal signs of periodontal disease, using individually made acrylic stents. When the probe was in place and a foot switch depressed, the measurement was stored on the computer to the nearest 0.1 mm. The measurements were performed by one periodontist and one hygienist during one visit, and were then repeated by the same periodontist and another hygienist during a second visit. The results showed high correlations between the periodontist and the hygienist during one visit, between the two visits for the periodontist, and between the two hygienists at two different visits. The subject threshold for attachment loss was calculated according to Haffajee and co-workers, and was found to average 0.84 mm for the measurements performed by the periodontist and the hygienist during the same visit. For the periodontist during two separate visits and for the two different hygienists, the average threshold was 0.99 and 1.02 mm, respectively. Duplicate measurements were also performed by one periodontist at one visit on 10 patients with advanced periodontal disease. The average subject threshold for these patients was 0.60 mm. It may be concluded that with the constant force electronic probe, loss of attachment can be detected earlier than when conventional instruments are used.

Dental Hygienists↗
PubMed1988

Mutants of Actinomyces viscosus T14V lacking type 1, type 2, or both types of fimbriae.

Mutants of Actinomyces viscosus T14V lacking type 1 or type 2 fimbriae or both were selected by their failure to react with rabbit antibodies against either or both fimbrial antigens. Immunospecific double labeling with iron dextran and ferritin-conjugated antibodies showed two types of fimbriae on individual cells of the parent organism, a single type on mutant strains with type 1+2- and type 1-2+ fimbriae and no labeled or unlabeled fimbriae on a type 1-2- fimbria-deficient strain. The mutational loss of one fimbrial antigen did not appear to affect expression of the other, since bacteria with one or two types of fimbriae bound similar amounts of a monoclonal antibody directed against the fimbrial antigen present on both bacterial phenotypes. The strong adsorption of strains with type 1+2+ or 1+2- fimbriae to saliva-treated hydroxyapatite and weak adsorption of those with type 1-2+ or no fimbriae was consistent with the known involvement of type 1 fimbriae in this attachment process. Similarly, the A. viscosus lectin was clearly associated with the expression of type 2 fimbriae, since only the strains with type 1+2+ or 1-2+ fimbriae participated in lactose-sensitive coaggregations with Streptococcus sanguis 34. Further studies using the fimbria-deficient mutant strains showed that aggregation of A. viscosus T14V in the presence of sialidase-treated human saliva involved both types of fimbriae, whereas neither type was required for the lactose-resistant coaggregation of the organism with certain streptococcal strains.

Actinomyces↗