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Biomedical subjects

J C Setcos

Publications and source records attributed to J C Setcos.

At least 37 records · Page 2Linked to original sources
PubMed1993

A worldwide survey of the teaching of glass ionomer (polyalkenoate) cements.

This paper reports the findings of a worldwide survey of the teaching of glass ionomer (polyalkenoate) cements (GICs). A total of 324 questionnaires was returned from the 650 dental schools included in the study (50 per cent response), with the response ranging from 100 per cent (Australasia) to 4 per cent (USSR). The findings indicate that most primary dental degree students in the majority of countries investigated are presently taught the use of GICs in a wide range of applications using techniques which largely conform with those recommended by the manufacturers of such materials.

Africa↗
PubMed1992

Inhibition of microbial adherence and growth by various glass ionomers in vitro.

This study measured the in vitro inhibition of growth and adherence of five oral bacteria by glass-ionomer materials. Disks were prepared from two cavity liners and four restorative class materials, by use of Teflon plates with circular wells, five mm wide and two mm deep. The bacterial species tested included: A. viscosus, S. mitis, S. mutans, L. casei, and S. sanguis. Growth inhibition studies were performed by the spreading of 0.1 mL of standardized inocula over agar plates produced with selective media, followed by the direct application of glass-ionomer disks onto the agar. On other plates, disks were placed onto uninoculated agars for 48 h, followed by bacterial inoculation. All agar plates were incubated under optimal growth conditions for each bacterial species. The four restorative materials were also placed aseptically into sterilized bovine incisors and placed into sucrose containing broth media, inoculated with S. mutans for three days. Adhering materials were disclosed and scored. An ion-exchange electrode was used to measure fluoride release over a seven-day period for all six glass ionomers. The two cavity liners and two of the restorative materials produced the largest growth inhibition zones by direct contact. No growth inhibition occurred when the specimens were allowed to come into contact with the agars prior to inoculation. All four restorative materials reduced bacterial accumulations on enamel surfaces by over 80%. Elevations in short-term fluoride release levels were positively correlated with growth inhibition.

Actinomyces viscosus↗
PubMed1992

A new light-activated adhesive composite: shear bond strength and microleakage.

A new light-activated adhesive composite has been formulated. Its shear bond strength and marginal microleakage were compared with glass ionomer cements: Fuji Ionomer Type II, Ketac-Fil and Ketac-Bond. The new material showed significantly (p < 0.05) higher bond strength to non-etched enamel (7.9 MPa) and dentin (7.3 MPa) than commercially available materials. It also performed significantly better (p < 0.05) in the microleakage test. Ease of use and the excellent marginal sealing ability of the new material are expected to allow considerable innovation in restorations of root caries, cervical erosion and other conditions where the marginal seal of the gingival cavosurface is difficult.

Aluminum Silicates↗
PubMed1992

A new light-activated adhesive cavity liner: an in vitro bond strength and microleakage study.

A new formulation of a light-activated calcium hydroxide-based cavity liner was developed for this study. Its shear bond strength and marginal microleakage in a Class V cavity preparation were compared to those of commercially available light-activated liners and conventional glass ionomer liners: GC Lining Cement (GC), Ketac-Bond (ESPE), Time Line (Caulk), Vitrabond (3M), XR lonomer (Kerr), and Zionomer (DenMat). The new formulation had significantly higher shear bond strength to dentin than the commercially available materials. Its microleakage along gingival (cemento-dentin) walls was statistically equivalent to one of the other materials and significantly better than all the others.

Analysis of Variance↗
PubMed1991

Connective tissue reactions to glass ionomer cements and resin composites.

This study evaluated the histopathologic reactions of rat connective tissue to two glass-ionomer cements (Fuji Cap II, Fuji Ionomer Type III) and two microfilled light-cured composite resins (Helio-molar Radiopaque and Helioprogress). IRM (zinc oxide-eugenol cement) was used as a control. Discs of the materials, 5 mm in diameter and 2 mm thick, that had set for 15 minutes were implanted under the dorsal skin of 75 Sprague-Dawley rats. There were 15 rats in each group and each animal received two identical implants. Five rats from each group were terminated at 7, 28 and 85 days after implantation. Histologic sections of the implant sites were stained with hematoxylin and eosin. Findings at all study periods indicated that Fuji Ionomer Type III elicited more intense reactions than the other materials. Reactions to Fuji Cap II, Heliomolar Radiopaque and Helioprogress, at all study periods, were comparable to each other and to IRM.

Acrylic Resins↗
PubMed1989

The teaching of posterior composites: a worldwide survey.

The findings of a worldwide survey of the teaching of posterior composites have been reported. In most schools in at least Africa, Australasia, Europe, North America and Japan (mean response, 70 per cent) the undergraduate course in operative dentistry includes some consideration of posterior composites. However, the teaching in relation to these materials is typically limited and rarely includes practical exercises let alone requirements to gain clinical experience of the use of these materials. The data collected in respect of the materials and techniques considered appropriate for posterior composites was essentially consistent and in keeping with most of the recent authoritative literature in this field. It is concluded that many schools should review their approach to the teaching of posterior composites.

Bicuspid↗
PubMed1989

Adaptation of acrylic resin dentures as influenced by the activation mode of polymerization.

With the advent of newer methods of activation of the polymerization of denture base resins, there is a need to compare dentures constructed using various modes of activation such as heat, light, and microwave energy. This study compares the dimensional accuracy of a conventional heat-activated acrylic resin poly (methyl methacrylate) with a new pour resin, a visible light-activated resin, and microwave-activated acrylic resin, all polymerized for denture bases. All groups showed a processing contraction; the poorest-fitting group was processed in a brass flask and a water bath at 70-100 C, using a heat-activated resin (Acron); the relatively new light-activated resin (Triad) produced dentures of intermediate accuracy, as did Acupac 20, when either heat- or microwave-activated. The two best-fitting groups were prepared from an autopolymerizing resin (PERform) and the microwave-activated resin (Acron MC).

Chemical Phenomena↗
PubMed1988

Marginal fracture of posterior composite resins.

This study assesses the early cavomarginal breakdown of the newer posterior composite resin restorations compared with that of amalgam restorations. A total of 432 posterior composite restorations and 73 amalgam restorations were examined: 121 composite restorations (28%) and 44 amalgam restorations (60%) clinically showed a marginal crevice at some point on the cavosurface margin of the restoration at 6-month, 1-year, and 2-year recalls. The largest single reason for poor marginal adaptation was marginal fracture. Up to 2 years, the marginal integrity of the studied posterior composites was superior to that of an amalgam alloy. It was determined that smaller cavities, greater bulk of resin at the margin (especially at functional cusp areas), and well-finished margins without overfiling seem to reduce the occurrence of marginal fracture on composite resin restorations.

Composite Resins↗
PubMed1987

Margin quality and microleakage of Class II composite resin restorations.

Margin quality and isotope microleakage analyses of Class II restorations placed in extracted human molars were compared using various composite resins and placement techniques. At occlusal margins, the traditional (experimental) composite resin restoration placed by the incremental technique showed less microleakage than did the traditional (commercial) [corrected] composite resin restoration placed by the bulk technique. In each group, the occlusal and proximal adaptations had significantly higher "excellent margin" than did the cervical adaptation. Thus, the marginal adaptation at the cervical aspect of conventional Class II composite resin restorations may present a problem with respect to microleakage.

Calcium Radioisotopes↗
PubMed1984

In vivo and in vitro wear of potential posterior composites.

The influence of cavity size, material composition, and curing mechanism on wear resistance of Class II MOD resin restorations was analyzed quantitatively. Wear resistance tends to increase both as cavity size decreases, and also from chemical- to light- to heat-cured. As to wear, among the composite resins tested, there was no acceptable resin-based amalgam substitute.

Chemical Phenomena↗
PubMed1983

New finishing instruments for composite resins.

The trimming of composite resin restorations encompasses gross finishing, contouring, fine finishing, and polishing. A series of aluminum oxide-coated flexible disks have been marketed and are suitable for that purpose. However, their use is confined to directly accessible convex surfaces. For precise finishing of small delineated areas, and for concave and occlusal surfaces, rigid rotary instruments are necessary. The currently used stones and tungsten carbide burs are ineffective with microfilled composite systems. Thus, a series of finishing burs coated with 40- and 15-microns diamond chips were evaluated because of the superior grinding effectiveness as compared with existing instruments. Surface roughness measurements, and qualitative and quantitative SEM evaluations, indicate that these fine and superfine diamond finishing burs produce surfaces on composite resins as smooth as tungsten carbide burs and stones. At the same time, they cause less surface and subsurface damage or marginal fractures on composite resin restorations. The three-year clinical experience is generally favorable. Further quantitative clinical studies are warranted.

Composite Resins↗