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Biomedical subjects

W Scherer

Publications and source records attributed to W Scherer.

At least 19 recordsLinked to original sources
PubMed1992

Shear bond strength of a 4-META adhesive system.

This study evaluated the shear bond strength between amalgam and amalgam, amalgam and composite resin, and amalgam and dentin using a 4-META adhesive. Eighty samples were divided into four groups of 20 and were then divided into subgroups of 10 samples for thermocycling procedures. This study indicated that amalgam bonded to amalgam with a 4-META adhesive yielded bond strengths that were weaker than the shear strength of amalgam itself (p less than 0.05), and that thermocycling appeared to significantly weaken bond values (p less than 0.02).

Adhesives↗
PubMed1992

Diastema closure: a case report.

This clinical study describes two combined modalities of treatment, orthodontic and porcelain laminate placement, to facilitate diastema closure. Geristore, a dual-cure fluoride-releasing composite was mixed to bond orthodontic brackets in place. H6 elastic bands were used with the orthodontic brackets to close the diastemas sufficiently and to allow the placement of Cerinate porcelain laminates to produce a beneficial cosmetic effect.

Dental Veneers↗
PubMed1992

Bonding composite to glass ionomer with adhesive resin cements.

This study was to determine the bond strength of composite to glass ionomer using the following adhesive resin cements: Imperva Dual, CB Metabond, All-Bond, Geristore, and Panavia. All materials were mixed following the manufacturer's specifications. Bonded samples were thermocycled for 2000 x between 5 degrees C and 55 degrees C. Shear bond strengths were determined using an Instron Testing Machine. No statistical differences were noted between materials at the p < .05 level of significance. In addition, scanning electron micrographs were taken of the primed glass ionomer surfaces. These micrographs revealed varying amounts of matrix dissolution along with roughened surface topographies.

Analysis of Variance↗
PubMed1992

Bonding Ni-Cr alloy to tooth structure with adhesive resin cements.

This study was to determine the shear bond strengths of Ni-Cr alloy to Ni-Cr alloy (Group I), Ni-Cr alloy to enamel (Group II), and Ni-Cr alloy to dentin (Group III) using Imperva Dual, DC Metabond, All-Bond, Geristore, and Panavia. All bonded specimens were thermocycled 2000 x (5 degrees C-55 degrees C) after 24 hours and subjected to shear bond testing on a Universal Instron Testing Machine. In all groups of the study, Imperva Dual and CB Metabond had significantly (p < .05) higher bond values than Panavia.

Analysis of Variance↗
PubMed1992

Compressive and diametral tensile strength of titanium-reinforced composites.

This article determines the compressive and diametral tensile strength of two titanium-reinforced composites (Bis-GMA-based), Ti-Core and Flexi-Flow cem with titanium and compares their strengths to dentin and commercially available core materials and cements. In addition scanning electron microscope (SEM) photographs were taken of Ti-Core and Flexi-Flow cem with titanium. Compressive and tensile loading was performed on a modified universal testing apparatus. Ti-Core and Flexi-Flow cem with titanium were measured to have compressive strengths of 41,132 and 41,876 psi and tensile strengths of 5219 and 4930 psi, respectively. Statistically (ANOVA, one-way analysis of variance), these titanium-reinforced composites are stronger in compressive and tensile strength than Ketac-Silver, Fleck's zinc cement, Durelon, Ketac-Cem, and GC Miracle Mix. Both titanium-reinforced composite materials approach the compressive and diametral tensile strengths of dentin (43,100 and 6000 psi). SEMs revealed that the titanium was uniformly and homogeneously interspersed within the resin matrix of the material.

Analysis of Variance↗
PubMed1992

Visible light-activated glass ionomer cement: use as liners/bases and restoratives.

Traditional glass ionomer cements were sensitive to moisture during the initial state and were subject to dehydration as the material began to harden. Preliminary findings from in vitro studies and clinical trials indicate that a new light activated glass ionomer cement exhibits high shear bond values, reduced microleakage and improved aesthetics.

Dental Cavity Lining↗
PubMed1992

Carbamide peroxide at-home bleaching agents. An update.

Interest in the use of bleaching for treatment of discolored teeth is increasing. Bleaching, especially at-home mouthguard bleaching, is considered by many professionals to be the most conservative, non-invasive treatment modality currently available.

Carbamide Peroxide↗
PubMed1991

Removal of intrinsic enamel stains with vital bleaching and modified microabrasion.

This study utilized a vital bleaching agent as well as an enamel microabrasion compound with low hydrochloric acid concentration to remove intrinsic stains on the facial surfaces of anterior teeth. In addition, scanning electron microscopic analyses of enamel from extracted teeth compared the etching pattern of the commercial compound used in this study to 18% hydrochloric acid. Type 1 and Type 2 etch patterns were observed with 18% hydrochloric acid after 5 and 20 seconds, respectively. Milder and more diffuse etch patterns were observed with the enamel microabrasion compound. A conservative form of treatment to remove intrinsic stains would employ the use of a vital bleaching agent, followed by an enamel microabrasion compound.

Acid Etching, Dental↗
PubMed1990

[Malaria tropica in HIV infection].

This is a case report of a 24 year-old woman who is HIV-infected since three years (stage III B, CDC). She developed malaria tropica during her touristic stay in the Cameroons, Africa. No clinical complications were detectable even though she had a high parasitemia of 18% blood cells infected with Plasmodium falciparum. After quinine therapy defervescence occurred and blood smears were continuously free of malaria parasites. P. falciparum infection may increase HIV-related immunosuppression which favours the earlier occurrence of AIDS indicative opportunistic infections. Malaria in combination with HIV-infection can lead to a higher parasitemia; this does not necessarily lead to a higher rate of complications.

Animals↗
PubMed1990

Comparison of microleakage between direct placement technics and direct inlay technics.

Laboratory studies have indicated that improvements in the physical properties of composite restorations, especially for posterior teeth, may be obtained if these materials underwent heat treatment prior to insertion. The purpose of this study was to compare the microleakage in Class II restorations ending on cementum/dentine when these preparations were restored by a direct placement composite resin as opposed to a direct inlay composite resin. Thirty-six human posterior mandibular teeth were used in this study and randomly divided into three equal groups; Group I was prepared and restored with the composite Ful-fil in a direct placement technique. Groups II and III were prepared and restored using a direct composite resin inlay technique. The material used in Group II was Brillant D.I.; that of Group III, Ful-ful. All preparations terminated 1.0 mm apical to the CEJ. The composite resin patterns of Groups II and III were oven-tempered before cementing with D.I. Duo Cement. Specimens were thermocycled 125 times between 5-55 C. Microleakage was noted cervically on a scale of 0 to 5. The composite Ful-fil, used as a direct placement material, exhibited less leakage (P less than 0.05) than either the Brillant D.I. composite or Ful-fil composite when these materials were placed as direct composite inlays.

Bicuspid↗
PubMed1989

Clinical features and management of amebic liver abscess. Experience from 29 patients.

29 patients with amebic liver abscess were evaluated in a study to examine clinical picture, laboratory data, epidemiology, radiologic methods, and therapy. Since the clinical picture was unspecific a considerable amount of misdiagnoses occurred, and often originated from pulmonary symptoms. To establish diagnosis one should rely on the triad with positive amebic serology, intrahepatic scanning defects, and clinical picture with fever, right upper quadrant pain, and hepatomegaly. Nearly all patients had an exposure history of travel or immigration from endemic areas in the tropics. Medical therapy with metronidazole alone is highly effective and leads to defervescence and clinical improvement usually within 3-5 days. Invasive procedures, such as needle aspiration or surgical drainage of the abscess are rarely needed; these invasive methods neither shorten the course of the disease nor improve prognosis.

Adult↗
PubMed1989

Microleakage of three glass ionomer cement bases.

This study compared the marginal leakage in Class V restorations using three different GIC bases and a composite resin sandwich. The specimens were randomly divided into three equal groups, and the following GIC materials were used as bases: Group I: Ketac-Bond Aplicap; Group II: GC Dentin Cement; Group III: Shofu GlasIonomer Base. The results indicated less microleakage in restorations with a Shofu GlasIonomer Base while no statistical differences were noted between Ketac-Bond Aplicap and GC Dentin Cement.

Dental Cements↗
PubMed1989

Antimicrobial properties of glass-ionomer cements and other restorative materials.

The antimicrobial properties of 14 different restorative materials, nine of which were glass-ionomer cements, were compared and observed in this study. The materials were mixed according to manufacturers' specifications and exposed to four types of bacteria commonly found in caries and plaque. Zones of bacterial inhibition were measured for all materials in millimeters. Glass-ionomer cement materials, materials containing zinc oxide, and amalgam produced measureable zones of inhibition.

Bacteria↗
PubMed1989

Evaluation of the ability of glass-ionomer cement to bond to glass-ionomer cement.

This study investigated the cohesive bond strengths of glass-ionomer cement at three setting and etching intervals and compared these bonds to the shear strength of the material itself. Bonded cylinders were created and then sheared using the Instron Universal Testing Machine. Analysis of bond values of glass ionomer added to glass ionomer indicate bond variability and low cohesive bond strength of the material. Bond values of unbonded glass-ionomer material indicate that the material itself is stronger than bonds established between bonded samples.

Dental Bonding↗
PubMed1989

Microleakage of capsulated glass ionomer cements.

The purpose of this study was to compare marginal leakage in Class V preparations restored and finished within 20 minutes with two different capsulated and syringeable restorative glass ionomer cements. The materials were inserted and finished following manufacturer's specifications. Specimens were thermocycled 125x in fuchsin dye at 5 degrees C and 55 degrees C, mounted in acrylic and sectioned faciolingually. Microleakage was observed and rated on a scale of 0 to 3 at both enamel and cervical margins. The results of this study indicate that: 1) both materials exhibit marginal leakage at enamel and cervical margins, 2) no significant difference in microleakage was found between these materials, and 3) enamel margins leaked less than cementum/dentin margins with each material.

Dental Bonding↗
PubMedDate not supplied

Antimicrobial properties of VLC liners.

The antimicrobial activity of several visible light cured glass ionomer and liner materials against three bacteria commonly found in the oral cavity is discussed. Vitrabond light cure glass ionomer produced zones of inhibition against all the bacteria tested in this study. It appeared to resemble a true glass ionomer cement in regard to its antimicrobial properties whereas the other materials used in this study appeared to possess no antimicrobial activity.

Actinomyces↗