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Biomedical subjects

W Scherer

Publications and source records attributed to W Scherer.

At least 37 records · Page 2Linked to original sources
PubMed1996

Root surface biomodification using a dentin bonding conditioner.

OBJECTIVE: The purpose of this investigation was to compare by scanning electron microscopy (SEM) the surfaces of roots treated with a dentin conditioning agent and other materials that have been used routinely in periodontal therapy for root surface demineralization, namely, citric acid and tetracycline hydrochloride. MATERIALS AND METHODS: Sixteen freshly extracted human teeth were randomly divided into four equal groups; each tooth was hand scaled and planed prior to root surface conditioning with citric acid, tetracycline hydrochloride, and a dentin bonding conditioner; Tenure Dentin Conditioner (DenMat Corporation, Santa Maria, CA). The last has been used previously in conjunction with a resin-ionomer barrier in cases involving guided tissue regeneration. Root specimens were prepared for scanning electron microscopy and representative micrographs were taken at 1000x and 2000x. RESULTS: The results of this study indicate that there are morphological similarities between surfaces obtained with the dentin conditioning agent and the other acidic materials that are used routinely in periodontal regenerative therapy. CONCLUSIONS: Root surface demineralization has been shown to remove the smear layer, and provides a surface which is conductive to mechanical adhesion and cellular mechanisms for growth and attachment.

Acid Etching, Dental↗
PubMed1996

The use of a resin-ionomer in varying restorative procedures: case reports.

UNLABELLED: The purpose of this paper is to describe the subgingival placement of a resin-ionomer for several restorative procedures, namely, root resorption, endodontic perforation, and root fracture. After endodontic therapy, a combination scallop flap (in attached gingiva)-full thickness flap (at affected tooth only) was raised to gain access to the lesion and root defect. The root defects were prepared with ultra-sonic instruments under an operating microscope and the preparations treated with Tenure Dentin Conditioner (DenMat Corporation, Santa Maria, CA). The preparations were washed and lightly air-dried, and the Tenure All-Purpose Bonding System (Den Mat Corporation, Santa Maria, CA) was placed in the prepared areas. Geristore resin-ionomer (DenMat Corporation, Santa Maria, CA) was then syringed into the preparations and either light-activated or allowed to undergo a chemical set. Once set, the material was finished with fine diamonds under water spray. The flap was then sutured to place with Gore-Tex sutures when a non-resorbable Gore-Tex membrane (Gore Corporation, Flagstaff, AZ) was used or 4-0 nylon sutures when resorbable Guidor membranes (Butler Company, Bensenville, IL) were used. The sutures were removed after two days. The patients were observed weekly for the first month and then monthly until released. No untoward effects have been observed during the time frame of this project. All of the cases have been responding satisfactorily. CLINICAL SIGNIFICANCE: The cases presented indicate that a resin ionomer, Geristore, may be used as a subgingival restorative, and may be placed in lesions thought to be unrestorable. Thus, teeth may be saved that were previously designated to be extracted.

Drug Evaluation↗
PubMed1995

Removal of enamel surface stains with at-home vital bleaching.

PURPOSE: To report the results obtained with an at-home bleaching product in the removal of enamel surface stains. MATERIALS AND METHODS: An individualized vacuum-formed mouthguard was fabricated and scalloped so that the terminal portion of the mouthguard ended approximately 1.0 mm from the gingiva. The patient was instructed to brush his teeth with Rembrandt Whitening Toothpaste prior to and after using the Rembrandt Gel Plus bleaching gel. In addition, the patient was informed as to the proper method of placing the gel in the mouthguard, and inserting the mouthguard into his mouth. The mouthguard was to be worn for 2-3 hours a day for a 2-week period. RESULTS: At the end of 2 weeks, the enamel surface stains were removed through the bleaching process.

Adult↗
PubMed1995

Use of a resin-ionomer in guided tissue regeneration: case reports.

The cases presented in this report illustrate: (1) the potential for a fluoride-releasing resin-ionomer (Geristore) to be used as a sealant between an e-PTFE membrane (Gore-Tex) and tooth structure during a guided tissue regeneration, and (2) the potential for a resin-ionomer to function as a barrier in guided tissue regeneration. In the first case, the e-PTFE membrane was trimmed to only cover the area to be treated prior to its placement over the lesion. The resin-ionomer was mixed following manufacturers specifications, placed on four corners of the pre-trimmed membrane and luted into place. In the second case, the resin-ionomer alone was placed over the lesion, teased off the lesion with a curette while in a semi-set state, and luted into place with freshly mixed material after it set completely. These cases provide preliminary clinical evidence that a resin-ionomer may be used subgingivally for guided tissue regeneration.

Adult↗
PubMed1994

Alcohol-containing mouthwashes: effect on composite hardness.

This study evaluated the effects of alcohol-containing mouthwashes on composite resin hardness. Eighty hybrid composite discs were fabricated and divided into eight equal groups: Listerine, Scope, Viadent, Plax, Lavoris, Clear Choice, and Rembrandt Mouth Refreshing Rinse. Water acted as a control. All of the discs were immersed by group in their respective liquids for two minutes a day over a period of six months. Disc hardness was measured six times at the center and periphery using a Barcol impressor. The baseline values were taken for each disc and compared to the test values at the end of six months. The results of the study indicate that the alcohol content in mouthwashes can affect composite hardness. This softening affect can be directly related to the percentage of alcohol in the mouthwash.

Analysis of Variance↗
PubMed1994

An in vivo comparison of antimicrobial activities of four commercial mouthwashes.

The purpose of this in vivo double-blind study was to determine and compare the antimicrobial effectiveness of four commercial over-the-counter mouthwashes and a water control. Two of the products tested contained alcohol (Listerine and Scope) and two products were alcohol-free (Rembrandt Mouth Refreshing Rincs and Clear Choice). The antimicrobial efficacy of the products was determined against aerobic, microaerophilic, and anaerobic bacteria in saliva. Thirty human subjects participated in the study. At each experimental session for a given subject, a pretest saliva sample was taken. This sample was divided and used to grow three bacteria cultures under the different incubation environments. After giving the pretest sample, the subject rinsed with one of the commercial mouthwashes or the water control for 30 seconds, then waited one hour at which time a posttest saliva sample was collected. Again, the sample was divided and used to culture the different type of bacteria. Following a 48-hour incubation period, the numbers of microbial colonies on each plate were counted and compared. The results indicated that all of the mouthwashes tested performed significantly better than the water control. Both of the non-alcohol-containing products showed efficacy in inhibiting aerobic, microaerophilic, and anaerobic bacteria. Rembrandt Mouth Refreshing Rinse and Listerine inhibited all three types of bacteria, and were not significantly different from each other in efficacy. The Rembrandt mouth wash inhibited all three types of bacteria more effectively than Clear Choice mouthwash, and inhibited two of the three types of bacteria more effectively than Scope mouthwash.

Analysis of Variance↗
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↗