PubMed Health⌕ Search

Biomedical subjects

W W Barkmeier

Publications and source records attributed to W W Barkmeier.

At least 19 recordsLinked to original sources
PubMed1992

Laboratory evaluation of adhesive systems.

Adhesive bonding of resin materials to acid-conditioned enamel is a clinically proven technique in preventative, restorative, and orthodontic procedures. Laboratory evaluations of etched-enamel resin bonding have shown excellent bond strengths and the virtual elimination of marginal microleakage. Adhesion to dentin has been more of a challenge. Earlier-generation dentin bonding systems did not yield high bond strengths in the laboratory or prevent marginal microleakage. Newer-generation adhesive systems generally use a dentin conditioner to modify or remove the smear layer and a subsequent application of an adhesive resin bonding agent. Laboratory evaluations of newer systems have shown bond strengths that approach or actually exceed that of etched enamel resin bonding. Bond strengths have improved with the evolution of dentin bonding systems, and microleakage from the cementum/dentin margin has been significantly reduced or prevented with the newer systems. Although laboratory testing of adhesive systems provides a mechanism to screen and compare newly developed systems, clinical trials are essential to document long-term clinical performance.

Adhesives↗
PubMed1992

Scanning electronic microscopic analysis of the local effects of a periodontal scaling gel on selected surfaces.

A laboratory study was conducted to evaluate the effects of a periodontal scaling gel on mineralized tooth surfaces and selected dental restorative materials. SofScale Scaling Gel (Ash/Dentsply) was applied on enamel and dentin surfaces of freshly extracted human teeth. These surfaces were evaluated before and after a gel treatment. The gel was also applied to glass ceramic, amalgam, hybrid composite, feldspathic porcelain, glass ionomer, gold alloy, silver palladium alloy, and non-precious alloy. The contact times with these materials and substances ranged from two minutes to sixteen hours. Scanning electron microscopy (SEM) was employed to evaluate differences between treated and control surfaces. Intact enamel and dentin surfaces appeared cleaner without obvious morphological changes with gel contact times up to twelve minutes. When treated for sixteen hours, the enamel exhibited an etch pattern characteristic of a surface treated for sixty seconds with 37% phosphoric acid. No morphological changes were observed on the surface of the restorative materials evaluated with contact times up to twelve minutes. Scanning electron microscopy indicates that SofScale Scaling Gel does not alter the morphological structure of restorative materials, intact enamel and dentin with gel contact times up to twelve minutes.

Cellulose↗
PubMed1992

A clinical evaluation of the effects of a periodontal scaling gel.

This research evaluated the in vivo effects of a periodontal scaling gel used in routine prophylaxis. Fifteen adult patients with moderate to heavy calculus were selected for full mouth hand scaling and prophylaxis using a split mouth design, employing SofScale Scaling Gel in experimental quadrants. Patients and operators were asked to evaluate differences between control and treated quadrants. The following parameters were evaluated during and after treatment: Gingival effects, tooth sensitivity, ease of calculus removal, and overall patient comfort. In addition pre- and post-treatment tooth surfaces were evaluated with scanning electron microscopy using a replicate technique. No tooth sensitivity or soft tissue irritation was observed in any control or experimental quadrants. Calculus removal was independently judged by operators to be easier in the gel treated quadrants when compared to untreated control quadrants. Scanning electron microscopy revealed cleaner enamel and root surfaces with no obvious morphological changes in mineralized tissues. The results of this study demonstrate the safety of the scaling gel and the increased effectiveness of calculus removal during hand scaling of teeth treated with this gel.

Adult↗
PubMed1991

Post polymerization strength values of an argon laser cured resin.

A hybrid composite resin, Prisma APH, and a microfilled composite resin, Silux Plus, were compared regarding diametral tensile strength values following conventional visible light polymerization and argon lasing. The time interval between resin polymerization and physical property testing ranged from 1 hour to 20 days. Results demonstrated considerable mean tensile strength value variation in the earlier phases of the study with a lessening of the differences between the tensile strengths achieved by each method of polymerization as the 20 day interval was approached. It was concluded that composite resin testing protocols should be lengthened to be able to fully assess the effects of the widely variant, time dependent mean test results.

Argon↗
PubMed1991

Dentinal bond strengths and microleakage of a 4-META adhesive to amalgam and composite resin.

A 4-META-containing adhesive was evaluated for its ability to bond a composite resin and two types of amalgam to dentin. One group of composite resin was tested after 24 hours and another group after 24 hours of thermocycling. Shear bond strengths were: composite resin at 24 hours = 22.38 MPa; thermocycled composite resin = 20.86 MPa; spherical alloy = 3.38 MPa; admixed alloy = 3.84 MPa. Microleakage was evaluated after the 4-META adhesive was applied to cavity preparations and compared to that of a group treated with a cavity varnish. There was statistically significantly less microleakage in the 4-META group at both the occlusal and gingival margins.

Coloring Agents↗
PubMed1991

Degree of composite resin polymerization with visible light and argon laser.

A study was conducted to compare the degree of resin polymerization achievable using conventional visible light techniques and argon lasing. High performance liquid chromatography was used to extract unpolymerized resin from microfilled and small particle composite resin samples following photoactivation with visible light and the argon laser. It was determined that a significantly greater degree of microfilled resin polymerization was achievable following argon lasing compared to exposure to conventional visible light techniques. Although the small particle composite resin samples were polymerized as well as, or slightly better, with the argon laser, the differences were found to be insignificant. As a result, the argon laser should be considered a potentially advantageous method of initiating the polymerization of dental composite resin restorations.

Argon↗
PubMed1991

Dentinal shear bond strength, microleakage, and contraction gap of visible light-polymerized liners/bases.

The bond strength and microleakage patterns of three light-curing glass-ionomer cement liners/bases (Vitrebond, XR Ionomer, and Zionomer) were evaluated and compared to a fluoride-releasing resin (TimeLine) designed for the same use. Bond strength tests were performed at 24 hours and 7 days. At 24 hours Vitrebond, Time-Line, and Zionomer had statistically significantly greater bond strengths than XR Ionomer. At 7 days, Vitrebond had a statistically significantly stronger bond than the others. Microleakage was evaluated after 24 hours of thermocycling. Vitrebond and XR Ionomer had statistically significantly less leakage than the others, while TimeLine had significantly more leakage than the others. Polymerization contraction gaps between the liners/bases and dentin were examined with scanning electron microscopy. Contraction gaps were approximately 10 microns with Vitrebond and XR Ionomer and 5 microns with TimeLine. A contraction gap generally was not observed with Zionomer.

Dental Bonding↗
PubMed1991

Current status of adhesive resin systems.

The advanced third-generation bonding agents have created excitement as they have the potential to develop effective dentin bonding. These materials have shown better bond strengths and less marginal microleakage than the previous generations of adhesives. Enamel acid etching and the new primer/adhesive systems can enhance the retention rates of resin restorations and reduce or eliminate marginal microleakage.

Adhesives↗
PubMed1979

Technique for an immediate temporary fixed tooth replacement.

A clinical technique for the immediate replacement of an extracted anterior tooth was presented. The clinical crown of the patient's extracted tooth was used as a pontic by attaching it to the adjacent teeth with acid-etch bonded resin. This technique provides a practical and esthetic immediate fixed tooth replacement that requires minimum materials and time.

Acid Etching, Dental↗
PubMed1979

Self-shearing retentive pins: a laboratory evaluation of pin channel penetration before shearing.

This laboratory study determined the depth reached by self-shearing pins in dentin pin channels. Pin channels were prepared with the self-limiting shoulder twist drill for each of the four systems tested. Mean channel depth reached for the various pin systems was: Stabilok (small), 2.31 mm; Stabilok (medium), 1.78 mm; Reten Pin, 1.40 mm; and TMS (Regular), 2.04 mm. A coparison was also made by calculating the mean percent of penetration in relation to the depth of prepared pin channel: Stabilok (small), 92.50%; Stabilok (medium), 63.62%; Reten Pin, 66.67%; and TMS (Regular) 81.75%.

Dental Instruments↗