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Biomedical subjects

B Guggenheim

Publications and source records attributed to B Guggenheim.

At least 55 records · Page 3Linked to original sources
PubMed1993

Periodontal repair or regeneration: structures of different types of new attachment.

The present study details the structural and ultrastructural features of healing events between the regenerated periodontal ligament and the root surface after experimental periodontal disease. Experiments were performed on dogs, and the concept of guided tissue regeneration was tested using resorbable polyurethane membranes. Light microscopy, scanning- and transmission electron microscopy were employed to determine if healing events involve regeneration (ie, process by which the architecture and the function are completely renewed) or periodontal repair (ie, healing of a wound by tissue that does not fully restore the architecture of a part). Regeneration occurred in parts of the roots only if some original cementum remained on the root surface after root planing. Repair was observed if peripheral dentin was removed by root planing as this layer was not reestablished. In areas remote from the base of the defect, new collagen fibrils, synthesized by fibroblasts and oriented perpendicular to the root surface, were spliced with severed ends of Sharpey's fiber bundles of original cementum. If circumpulpal dentin was exposed, intermingling between new fibrils with dentinal matrix fibrils occurred. In areas near the base of the defect, the first event was the formation of a cementoid by a cementoblast monolayer and subsequent formation of intrinsic fibrils oriented parallel to the root surface. Afterwards, the cementoblast monolayer disintegrated and extrinsic fiber bundles became anchored in the new cellular mixed fiber cementum. In these areas, linkage between new cementum and pre-existing tissues always occurred by interfacial intermingling of the fibrils, regardless of whether new attachment occurred at circumpulpal dentin or original cementum.

Animals↗
PubMed1992

Human root caries: histopathology of arrested lesions.

The histopathology of arrested root caries lesions was examined in extracted human teeth. The main structural characteristics of arrested lesions were the completely mineralized surface area and the formation of a distinct sclerosis of the dentinal tubules. Intertubular dentin was, with the exception of the dentinal tubules, fully mineralized up to the surface. Dentinal tubules near the surface were either filled with ghosts of microorganisms or with crystals of different shapes. Sclerosis of the dentinal tubules was characterized by the presence of three different patterns of intratubular mineralization that occur in distinct regions of the zone of tubular sclerosis. The patterns were distinguishable by the type of crystals and their association with organic structures such as collagenous fibrils or odontoblast processes. It is suggested that arrested lesions are based on (1) the formation of an inner barrier that interrupts the diffusion of substrata from the pulp to invaded bacteria, (2) the formation of an outer barrier by a compact, highly mineralized surface region which blocks the diffusion of products of bacterial metabolism into dentin, and (3) an area of mineralization which extends from the outer barrier toward the root canal within demineralized dentin. The present study demonstrates the considerable potential of caries lesions in dentin to become arrested, and subsequently partially remineralized. These phenomena seem to depend on the severity of an active lesion and its location on the root surface. This should be taken into account when diagnosing root caries lesions. The potential of root caries lesions to become arrested indicates that the treatment concept of active root caries lesions should be reconsidered.

Adult↗
PubMed1991

Cariogenicity of Milchschnitte (Ferrero GmbH) and apple in program-fed rats.

The cariogenicity of Ferrero Milchschnitte and apple was tested in rats using a frequency-controlled feeding machine. Twelve litters of Osborne-Mendel rats orally infected with Streptococcus sobrinus OMZ-176 and Actinomyces viscosus Ny-1 were used. Four treatment groups were tested: (1) cooked starch/sucrose 1:1 as positive control; (2) Ferrero Milchschnitte; (3) apple; (4) gastric intubation only as negative control. Groups 1-3 were additionally fed by gastric intubation with essential nutrients. Rats on Milchschnitte and apple had less fissure and smooth-surface caries than rats on a starch/sucrose diet, but significantly more than the negative controls. The Milchschnitte group exhibited less plaque extent than the positive and the negative control. The apple group showed a higher plaque extent and massively extended erosions on molar surfaces. The CFU means of S. sobrinus were decreasing from treatment 1-4. Although differences between treatments were not significant, they were associated by concomitantly decreasing caries incidence. The test foods were also assessed using intraoral plaque-pH telemetry in 6 human volunteers. Both Milchschnitte and apple were acidogenic in human telemetry. They can therefore not be regarded as safe for teeth.

Animal Feed↗
PubMed1990

Monoclonal antibodies for the detection of 'periodontopathic' bacteria.

The development of indirect immunofluorescence assays using MAbs as specific probes has made it possible to detect a variety of suspected periodontal pathogens in subgingival plaque, with exquisite sensitivity. The studies demonstrate high reproducibility of the results if different MAbs are used to assess the same bacterial species. Bacteroides forsythus, Bact. gingivalis, Bact. intermedius and Wolinella recta, but not Actinobacillus actinomycetemcomitans were found in sites of adult periodontitis with high prevalence but quite distinct degrees of colonization. The colonization levels of Bact. forsythus and Bact. gingivalis were significantly associated with the probing depth of the lesions. The investigations demonstrate the usefulness of serological analysis of plaque and indicate that several of the organisms implicated in the aetiology of periodontal diseases may be tolerated in high numbers in subgingival lesions, without periodontal destruction.

Actinobacillus↗
PubMed1990

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

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

Bacteroides↗
PubMed1990

Human root caries: histopathology of advanced lesions.

The histopathology of human root caries was examined in extracted teeth. The present study details several stages of advanced carious lesions in root dentin. Lesions of different severities were assessed by different optical methods. Four major root caries patterns were defined and significant differences between coronal and root caries elucidated. The patterns were distinguishable by (1) their location at the exposed root surface, (2) their mode of spreading towards the root canal and over the root surface, (3) their mode of bacterial spreading in dentin and (4) the role of dentinal defense mechanisms. In addition, a comparison of clinical and histological classification of lesions revealed that the carious process extended much deeper towards the root canal and had a higher degree of both bacterial infection and dentin demineralization than could be predicted by clinical examination.

Adult↗
PubMed1990

Histopathology of root surface caries.

The histopathology of active and arrested human root caries was examined in extracted teeth by different optical methods. Significant differences were observed between the mechanisms operating on the various dental structures. Three different patterns of initial cementum and dentin lesions could be distinguished, depending on the severity of the cariogenic attack, the degree of sclerosis of the peripheral dentin, and the presence of calculus. Advanced lesions were characterized by various patterns of demineralization. In particular, a massive lateral spread of bacteria into intertubular dentin was observed. Consequently, unaffected dentinal areas became continuously undermined. In arrested lesions, either a partial or complete mineralization of the intertubular dentin was apparent. Dentinal tubules were sclerosed passively by re- or precipitation of Ca and PO4 ions. In contrast, tubules filled with ghosts of bacteria appeared mineralized by fine-granular crystals. Our observations indicate that both the arrestment and the remineralization of active lesions depend on (1) the degree of active sclerosis of dentinal tubules in areas underlying the lesion, (2) the degree of the bacterial infection of the dentin, (3) the degree of progression of the lesions, and (4) the location of the lesions at the various root surfaces. It is suggested that remineralization of active lesions can occur. This supports the concept of non-invasive treatment of root caries lesions without cavitation.

Dental Caries↗
PubMed1989

Human root caries: histopathology of initial lesions in cementum and dentin.

The histopathology of human root caries was examined in extracted teeth by different optical methods. The present part of the study details the sequential stages of initial caries in both cementum and peripheral dentin. Significant differences are shown between the mechanisms operating on the various dental hard tissues during development of caries. Histologically distinguishable reaction patterns depended on both the degree of the cariogenic challenge and the respective structural features of cementum and peripheral dentin. Earliest lesions, histologically visible as small clefts traversing cementum and extending into peripheral dentin, were clinically not detectable. Cementum was stepwise destroyed until peripheral dentin became exposed. The exposed peripheral dentin was sclerosed and tubule-free. Demineralization of dentin preceded the degradation of the organic matrix. Frequently, a hypermineralized layer occurred in both cementum and exposed dentin. Its localization was not identical with the anatomical surface. Initial penetration of bacteria into peripheral dentin occurred along small clefts. Breakdown of the organic matrix was the final step in the destructive phase of the carious process.

Aged↗
PubMed1989

Prevalence of Bacteroides forsythus and Bacteroides gingivalis in subgingival plaque of prosthodontically treated patients on short recall.

The prevalence of Bacteroides forsythus and Bacteroides gingivalis in subgingival plaque of patients on short recall was analyzed in relation to the probing depth of the test sites. The subjects had excellent oral hygiene and therefore were unlikely to suffer from active periodontal destruction. Sixty-four subgingival plaque samples, taken from gingival or periodontal pockets with probing depths ranging from 1 to 8 mm, were quantitatively assessed for the presence of the two species using species-specific monoclonal antibodies in conjunction with a very sensitive indirect immunofluorescence technique. Both organisms were encountered in probes from sites as shallow as 2 mm, but the percentage of positive samples clearly rose in relation to the probing depth of the test sites. Overall, B. forsythus was found to colonize lesions earlier, that is at smaller probing depths, than B. gingivalis. Interestingly, whenever a sample was found to be positive for B. gingivalis it was also positive for B. forsythus. The numbers of B. forsythus and B. gingivalis and the total bacterial cell number found in the pockets were significantly correlated to the probing depth. However, with advancing probing depth the increase of the total cell numbers of the two Bacteroides species was considerably more pronounced than the increase of the total subgingival plaque cell number. The recall interval neither affected the frequency of sites positive for B. forsythus or B. gingivalis nor influenced significantly the proportions of the two species in subgingival plaque.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Microbiologic in vitro comparison of plaque-inhibiting mouthwashes].

The colonization on rat molars of S. sobrinus OMZ 176, S. mutans OMZ 376, or a combination S. sanguis OMZ 9 and S. sobrinus OMZ 176 after a short exposition to various fluoride solutions and disinfectants was tested in vitro. The test solutions included Act, Candida, Veadent, sodium fluoride, amine fluoride, stannous fluoride, zinc fluoride hexetidine, stannous fluoride/amine fluoride solutions, chlorhexidine and water. The sterilized rat molars were immersed in the above test solutions for 60 seconds, then incubated with streptococci in broth for 8 hours, again dipped into the same test solutions for 60 seconds and reincubated for an additional 30 hours. The streptococcal suspension contained 14C labelled sucrose solutions. The deposits on the molars were dissolved in 6N potassium hydroxide during 16 hours. Finally, the beta rays emitted by the dissolved radiolabelled suspension were counted using a scintillation counter. The sodium fluoride containing solutions exerted no or a very limited effect on the bacterial deposits. In contrast to the other test solutions, sanguinaria extract (Veadent mouth rinse) mildly inhibited the S. sobrinus and S. mutans deposits, but plaque formation by the combination of streptococci was not hampered. Zinc fluoride/hexetidine, amine fluoride and stannous fluoride/amine fluoride solutions had a distinct and significant inhibitory effect on S. sobrinus and S. mutans deposits, but only a weak effect when mixed cultures were used for plaque formation. Chlorhexidine significantly inhibited the deposits of the three bacterial strains used in these experiments.

Animals↗
PubMed1988

Specific and nonspecific inhibition of adhesion of oral actinomyces and streptococci to erythrocytes and polystyrene by caseinoglycopeptide derivatives.

Various caseinoglycopeptide derivatives prepared from mammalian milk were evaluated as inhibitors of hemagglutinations mediated by Actinomyces viscosus Ny1, Streptococcus sanguis OMZ9, and, for comparative purposes, plant lectins from Arachis hypogaea and Bauhinia purpurea. It was found that recognition of the beta-D-galactose-(1----3)-2-acetamido-2-deoxy-D-galactose carbohydrate chain by Actinomyces viscosus Ny1 organisms and Arachis hypogaea and B. purpurea agglutinins had similar structural requirements; in all cases, the desialylated bovine caseinoglycomacropeptide, on which several units of the above mentioned disaccharide are clustered, behaved as the most potent hemagglutination inhibitor. By contrast, none of the preparations tested inhibited erythrocyte agglutination by S. sanguis OMZ9. Thus, the desialylated bovine caseinoglycomacropeptide acts as a potent and specific inhibitor of oral Actinomyces adhesion to cell membranes (a soft surface) and could be used as a probe for the study of recognition mechanisms mediated by Actinomyces galactose-binding lectins. During the present study, both native and desialylated variants of the same bovine glycomacropeptide also totally prevented the adhesion of Actinomyces viscosus Ny1, S. sanguis OMZ9, and S. mutans OMZ176 to polystyrene surfaces. Comparative evaluations of various structurally different compounds gave the following results. Neither mono- nor disaccharides related to caseinoglycopeptide carbohydrates prevented adhesion; highly positively or negatively charged polypeptides and polysaccharides were either not or only moderately active. Besides these glycomacropeptides, an inhibitory activity was also exhibited by other mucin-type glycoproteins carrying short O-linked carbohydrate chains (including bovine submaxillary mucin), polyethylene glycol, and bovine serum albumin. Consequently, caseinoglycopeptide prevention of oral bacterial adhesion to polystyrene tubes (a hard surface) takes place with no species specificity and can be compared to nonspecific inhibition exhibited by various polymers with very different structural characteristics.

Actinomyces↗
PubMed1988

Production and characterization of monoclonal antibodies against Bacteroides forsythus and Wolinella recta.

Hybrid cell lines producing monoclonal antibodies against Bacteroides forsythus or Wolinella recta were generated by fusion of SP2/0 or FO myeloma cells with splenocytes from Balb/c mice immunized with formalinized cells of B. forsythus FDC 331 or W. recta D13a-g, respectively. Enzyme-linked immunosorbent assays and indirect immunofluorescence tests were used to analyze the distribution of the recognized antigens on a panel of 70 strains representing 35 taxa, most of which are members of the oral flora. All monoclonal antibodies--eight against B. forsythus and six against W. recta--proved specific for the immunizing species. Four of the monoclonal antibodies against W. recta recognized antigens expressed by only some of the tested W. recta strains, thus confirming the earlier noted antigenic heterogeneity of this species. Antibody binding patterns consistent with those previously described or distinct for new serogroups could not, however, be observed. Four of the eight anti-B. forsythus monoclonal antibodies bound to only two of the three tested B. forsythus strains. All the remaining monoclonal antibodies detected every strain tested of the respective species against which they were raised. Preliminary results indicated that several of these antibodies should be very useful for the direct identification and quantification of these organisms in subgingival plaque.

Animals↗