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Biomedical subjects

E I Weiss

Publications and source records attributed to E I Weiss.

32 records · Page 2Linked to original sources
PubMed1996

Interpretation of bitewing radiographs. Part 1. Evaluation of the presence of approximal lesions.

OBJECTIVE: Bitewing radiographs are the main tool for approximal caries detection. However, interpretation of findings is affected by numerous factors, such as beam angulation, exposure conditions, morphologic variations, etc. The objective of the present study was to compare the ability to detect virtually identical, artificial lesions in different tooth surfaces. METHODS: The in vitro model included preparation and radiologic evaluation of approximal artificial lesions in premolars and molars in depths ranging from 0.00 mm to 1.50 mm. RESULTS: Significant differences were found in the prospect of a lesion detection between the different lesion depths (p < 0.0000) and between the different surfaces examined (p < 0.05). The interaction between lesion depth and tooth surface was significant at the 0.0001 level (ANOVA with repeated measures). CONCLUSIONS: The results indicate that initial approximal lesions of uniform size are more readily detected in premolars than in molars and that the chance of an incipient lesion to remain undetected is twice as high in molars than in premolars.

Analysis of Variance↗
PubMed1996

Interpretation of bitewing radiographs. Part 2. Evaluation of the size of approximal lesions and need for treatment.

OBJECTIVE: The decision to treat initial approximal carious lesions is based mainly on interpretation of bitewing radiographs. In a previous report, it was shown that artificial approximal lesions of uniform size are more readily detected on radiographs in premolars than in molars. The objective of the present study was to compare the ability to evaluate the depth of similar size artificial lesions on radiographs and reach decisions concerning treatment, in premolars and molars. METHOD: Clinicians were asked to evaluate on radiographs, the size of in vitro prepared artificial lesions, and decide at which point they would perform a restoration. RESULTS: Significant differences were found in the evaluation of lesion depth between different tooth surfaces. The interaction between lesion depth and tooth surface originated from the examiners' trend to score same size lesions as penetrating deeper into the tooth in premolars than in molars. The probability of the examiners to decide on restorative treatment in shallow lesions (0.25 mm, 0.50 mm) was higher in premolars than in molars. CONCLUSIONS: The findings suggest that clinicians evaluate initial lesions as being deeper and more prone to treatment in premolars than in molars.

Analysis of Variance↗
PubMed1996

Assessment of antibacterial activity of endodontic sealers by a direct contact test.

It is recognized that endodontic success depends on bacterial elimination from the root and root canal system. Antibacterial activity of endodontic sealers can improve the success rate of endodontic treatment, provided the physical properties are not compromised. The aim of this study was to evaluate the antimicrobial properties of two endodontic sealers (AH26 and Endoflas) using a direct contact test (DCT) which was designed for this purpose. The DCT is based on measuring the effect of close contact between test bacteria and the tested material on the kinetics of bacterial outgrowth using a temperature controlled microplate spectrophotometer (THERMOmax). For comparison, the agar diffusion test (ADT) was performed for both materials. The results of the DCT showed that Endoflas was a significantly more potent bacterial growth inhibitor than AH26, whereas when assessed with the ADT, AH26 was capable of producing a larger inhibition zone than Endoflas. The DCT, by being quantitative and virtually independent of solubility and diffusion, was found more suitable to assay solid surfaces. The results demonstrated the added value of DCT in the study of the antimicrobial properties of endodontic sealers.

Analysis of Variance↗
PubMed1990

Identification of the rhamnose-sensitive adhesin of Capnocytophaga ochracea ATCC 33596.

The coaggregation of the Gram-negative microorganism Capnocytophaga ochracea ATCC 33596 with several Gram-positive bacteria, including streptococci, actinomyces and rothia, is mediated by rhamnose-sensitive adhesin(s). In the present study, MAbs against the C. ochracea adhesin(s) were prepared. These antibodies inhibited all the rhamnose-sensitive interactions, indicating that they recognize epitopes at or near the rhamnose binding site of the adhesin. The monoclonals served as probes in immunoblot analysis and recognized a polypeptide of Mr 155 K present in the wild-type organism but absent in a coaggregation defective mutant. It is concluded that the rhamnose-sensitive interactions of C. ochracea are mediated by a 155 K Mr polypeptide present on its outer surface.

Actinobacillus↗
PubMed1989

Bacteroides loeschei PK1295 cells express two distinct adhesins simultaneously.

Bacteroides loeschei synthesizes two distinct adhesins that mediate its coaggregation with Streptococcus sanguis 34 and Actinomyces israeli PK14. Streptococcal adhesin-specific and actinomyces adhesin-specific monoclonal antibodies were used to prepare antibody-coated 5- or 10-nm gold particles. These were used in immunoelectron microscopic studies to establish that essentially all bacteroides cells in a population express both adhesins. In general, the two sizes of gold particles representing each type of adhesin appeared to be spatially separated on neighboring fimbriae of B. loeschei. Deposition of antibody-coated gold particles, representing both types of adhesin, at or near the same fimbria was observed less frequently.

Antibodies, Monoclonal↗
PubMed1989

Fimbria-associated adhesin of Bacteroides loeschei that recognizes receptors on procaryotic and eucaryotic cells.

Inhibition studies with a set of adhesin-specific monoclonal antibodies and various sugars revealed that a fimbria-associated adhesin of Bacteroides loeschei recognizes receptors on both procaryotic and eucaryotic cells. These interactions permit this bacterium to attach to both types of cells, producing coaggregates in the presence of strains of Streptococcus sanguis and hemagglutination in the presence of neuraminidase-treated human erythrocytes.

Actinomyces↗
PubMed1988

Characterization of monoclonal antibodies to fimbria-associated adhesins of Bacteroides loescheii PK1295.

Bacteroides loescheii PK1295 fimbriae, which mediate the lactose-sensitive coaggregation with Streptococcus sanguis 34 and the lactose-insensitive coaggregation with Actinomyces israelii PK14, were injected into mice to raise adhesin-specific monoclonal antibodies (MAbs). Supernatants of hybridomas were screened for the capacity to inhibit coaggregation and agglutinate intact bacteria. Of the 10 MAbs that were isolated, 4 were specific and potent inhibitors of the coaggregation between B. loescheii and S. sanguis and two other MAbs specifically inhibited the B. loescheii-A. israelii interaction. None of the six MAbs which inhibited adherence were capable of agglutinating whole cells of B. loescheii, whereas the four remaining MAbs agglutinated whole cells but had no effect on coaggregation. Fab fragments of two MAbs, one that inhibited the coaggregation with S. sanguis and another that inhibited the interaction with A. israelii, also were shown to inhibit the respective coaggregation interactions, suggesting that each of the immunoglobulins recognized its adhesin molecule at or near the active sites. By immunoblotting or immunoprecipitation, the S. sanguis adhesin-specific MAbs reacted with a 75-kilodalton polypeptide present in fimbria-enriched preparations, whereas the A. israelii adhesin-specific MAbs recognized a 45-kilodalton polypeptide in the same preparations. By screening hybridoma supernatants directly for their capacity to block coaggregation, we isolated MAbs which were used to establish that the B. loescheii-S. sanguis and the B. loescheii-A. israelii interactions were mediated by different adhesins.

Actinomyces↗
PubMed1988

Localization and enumeration of fimbria-associated adhesins of Bacteroides loescheii.

Monoclonal antibodies that specifically inhibit coaggregation between Bacteroides loescheii PK1295 and its two gram-positive partners Streptococcus sanguis 34 and Actinomyces israelii PK14 were used to enumerate and localize two distinct types of fimbria-associated adhesins on the surface of B. loescheii. Binding studies with radiolabeled monoclonal antibodies indicated that a maximum (Bmax calculated from Scatchard plots) of approximately 400 adhesin molecules specific for S. sanguis and 310 adhesin molecules specific for A. israelii reside on the surface of the cell. Immunoelectron microscopy revealed that the adhesins were not an integral part of the fimbrial subunit; rather, they were usually found on the distal portion of the structures arranged in a random fashion.

Antibodies, Monoclonal↗
PubMed1987

Characterization of lectinlike surface components on Capnocytophaga ochracea ATCC 33596 that mediate coaggregation with gram-positive oral bacteria.

The interactions between Capnocytophaga ochracea ATCC 33596 and Streptococcus sanguis H1, Actinomyces naeslundii PK984, or Actinomyces israelii PK16 are dependent on specific recognitions between heat-sensitive adhesins on C. ochracea and heat-stable structures (probably carbohydrate-containing receptors) on the surfaces of these gram-positive coaggregation partners. The coaggregation of C. ochracea with each of these three organisms was inhibited by L-rhamnose and D-fucose and to a lesser extent by beta-methyl-galactoside. The reaction with S. sanguis was the most sensitive, while the coaggregation with A. israelii was the least sensitive and was only partially inhibited by each of the sugars that were considered to be effective inhibitors. A more effective inhibition of the coaggregation between C. ochracea and A. israelii was achieved by adding a combination of the 6-deoxysugars and N-acetylneuraminic acid. To further characterize the coaggregations, naturally occurring coaggregation-defective (Cog-) mutants of C. ochracea were obtained from several different selections. Three phenotypically distinct groups of mutants were were isolated. Type 1 mutants failed to coaggregate with S. sanguis only. Type 2 mutants lost ability to interact with both S. sanguis and A. naeslundii. Type 3 mutants failed to coaggregate with all three coaggregation partners. Characterization of the Cog- mutants by sugar inhibition studies made it possible to distinguish three classes of adhesin activity.

Bacterial Adhesion↗
PubMed1987

Fimbria-associated proteins of Bacteroides loescheii PK1295 mediate intergeneric coaggregations.

Bacteroides loescheii PK1295 serves as a coaggregation bridge between Streptococcus sanguis 34 and Actinomyces israelii PK14, two gram-positive oral bacteria that are otherwise unable to coaggregate. Whereas coaggregation with S. sanguis 34 is inhibited by lactose, no simple sugar was found that inhibited coaggregation with A. israelii PK14. Coaggregation-defective (Cog-) mutants of B. loescheii PK1295 were isolated for the purpose of identifying the surface components responsible for the interaction with each coaggregation partner. Selection for spontaneously occurring Cog- mutants gave rise to two phenotypic classes of mutants. Type I lost the ability to coaggregate with S. sanguis 34, whereas type II failed to coaggregate with either S. sanguis 34 or A. israelii PK14. Purified fimbriae from the parent agglutinated cells of both partners, and agglutination with S. sanguis 34 was inhibited by lactose. Denaturing polyacrylamide gel electrophoresis and immunoblot analysis demonstrated the presence of both a 75- and a 43-kilodalton (kDa) protein associated with parental fimbriae, but only a 43-kDa protein was seen with fimbriae prepared from the type I mutant. Neither polypeptide was found in similar preparations from the type II mutants. Our data suggest that coaggregation of B. loescheii PK1295 with both gram-positive partners is mediated by fimbria-associated proteins present on the surface of the gram-negative organism and that the 75- and 43-kDa polypeptides are responsible for the recognition of S. sanguis 34 and A. israelii PK14 cells, respectively.

Actinomyces↗
PubMedDate not supplied

Microleakage at the abutment-implant interface of osseointegrated implants: a comparative study.

Microleakage can occur at the abutment-implant (A-I) interface in osseointegrated implants and may cause malodor and inflammation of peri-implant tissues. The degree of microleakage at the A-I interface of 5 implant systems was comparatively assessed at varying closing torques. Using colored tracing probes driven by a 2-atm pressure system, the interface microleakage of Brånemark, Sulzer Calcitek, 3i, ITI, and Steri-Oss implants was determined spectrophotometrically. Microleakage through the A-I interface occurred in all systems, with variability between systems, samples, and closing torques. As closing torque increased from 10 Ncm to 20 Ncm to manufacturers' recommended closing torques, microleakage decreased significantly (P < .005) for all systems. Analysis of variance showed significant interaction between closing torques and the time course of microleakage, and between systems and the time course of microleakage (P < .001). The results indicate that fluids and small molecules are capable of passing through the interface of all the A-I assemblies studied. Presumably in an in situ situation, fluids containing bacterial byproducts and nutrients required for bacterial growth may pass through the interface gap, contributing in part to clinically observed malodor and peri-implantitis.

Analysis of Variance↗
PubMedDate not supplied

Continuous effect of pit and fissure sealing on S. mutans presence in situ.

PURPOSE: The effect of sealants on S. mutans presence in situ was investigated. METHODS: Four intact, fully erupted first permanent molars in each of 74 children, aged 6-8 years were required for inclusion in the study. Baseline examination included deft and plaque index. S. mutans presence on occlusal surfaces of the molars was evaluated, using a microbial replica method. Immediately after sealing the first permanent molars on one side, S. mutans presence in situ was re-evaluated, as well as three and six months thereafter. Three months after the initiation of the study, S. mutans presence was evaluated on the molars of the unsealed side, which were consequently sealed and re-evaluated immediately, and three months later. RESULTS: Positive correlation was found between deft scores, plaque indices and microbial replica values, at baseline. Sealing caused a significant reduction in S. mutans levels on the treated occlusal surfaces, in vivo (P < 0.001), which lasted, in most cases, up to six months. CONCLUSIONS: The data suggest that sealants enable a prolonged reduction of S. mutans presence in situ, indicating an additional prevention effect, by reducing one source of dissemination.

Child↗