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At least 649 records · Page 36Linked to original sources
PubMed1985

Porosities in a dental silver-palladium casting alloy.

Twelve single crowns were cast in a silver-palladium alloy by six different casting techniques. Polished sections of the crowns were inspected and photographically recorded by light microscopy. The area of the inspected section of the casting and the number and area of pores were recorded on the photographs by means of a digitizing table connected to a microcomputer. A great number of defects were observed unevenly distributed in all castings. Only small variations were observed between the various casting techniques.

Crowns↗
PubMed1987

Porosity of resin veneer materials.

The present investigation has studied the effects of different types of resins and different processing and curing methods on the number and size of pores occurring in resin facing materials. The mean number of pores per square millimeter varied between 0.5 and 4. The highest numbers occurred in unfilled heat-polymerized acrylic resin and in light-activated resin, whereas the lowest numbers were found in heat-polymerized micro-filled resin. Specimens processed in accordance with the free technique and cured under pressure consistently obtained lower numbers of pores than the corresponding specimens processed in a flask. Most of the pores were less than 50 micron diameter in all test groups. From a clinical point of view, a dense resin with a limited content of pores may give the most favorable results in terms of mechanical, esthetic, and hygienic properties of the veneer.

Acrylic Resins↗
PubMed1999

Porphyrin-Based Thin-Film Molecular Materials with Highly Adjustable Nanoscale Porosity and Permeability Characteristics.

Mesoporous thin films based on neutral, porphyrin-bridged, tetrarhenium "square" compounds (metallacycles) display permeability to molecules smaller than the dimensions of an individual square cavity, but blocking behavior toward larger species (see schematic representation). The characteristic permeant size cutoff can be systematically and predictably manipulated by decorating the walls of the porphyrin square with axially bound, mono-, bi-, and tetradentate ligands.

Journal Article↗
PubMed1975

[The effect of the density, porosity and surface properties of plastic bases of upper dentures on the palatal mucosa].

In a 14-day test with 50 probands, the effects of a heat-curing resin and a self-curing resin on the palatal mucosa of the test persons were tested by means of exfoliative cytology. It was shown that the keratinization index increased considerably during wearing the plates. It was not possible to demonstrate differences in the effect of heat-curing resins and that of self-curing resins. The different isolation with alginate film or tinfoil did not, in general, have any influence on the cytogram either. Roughness of the surface resulted in a slight increase of the intermediary cells.

Acrylic Resins↗