Search PubMed⌕ Search

Biomedical subjects

H J Rehberg

Publications and source records attributed to H J Rehberg.

At least 19 recordsLinked to original sources
PubMed1979

Trituration and creep.

Creep values of amalgam have been thought to be typical and nearly equal to their order of magnitude, depending on composition and particle shape. Recently it has been shown that trituration time may cause changes in creep magnitudes. The type of mixer and its frequency have contributed additional variabilities. These variations could not be related consistently to changes in creep values. Increases in condensation pressure did contribute to more predictable and constant values found with different mixing times.

Chemical Phenomena↗
PubMed1979

[Fluidity of casting materials in plane spreading].

The high fluid elastomer materials for making casts used for the double impression technique were studied with the so-called disc test in terms of their fluidity, diffusion, and layer thickness. The pressure exerted was also recorded at the same time. Our study showed that the low viscosity of the cast material and the application of small amounts were the prerequisites for obtaining the thinnest layer possible.

Dental Casting Investment↗
PubMed1977

The impression tray--an important factor in impression precision.

The flow behaviour of impression materials during impression taking was first investigated, and reference made to the pressure which occurs in the compound. Individual trays of plastic and shellac-bases which could be softened by heating, and a cold-curing tray material were then also examined: (1) for their distortion by slight loads upon the tray walls; (2) for their ability to retain their shape when stored, and (3) their distortion when temporarily warmed to body temperature. It was found that no tray materials, although graded according to type and thickness, can be considered rigid under experimental conditions, since distortions which were in some cases considerable could be measured. In laboratory experiments, the behaviour of the tray was then measured while taking impressions of models and the precision of the impression was examined at the same time. This confirmed the suspicion that the precision of an impression is to a considerable extent related to the tray material used. The smallest alterations were found when using cold-curing plastic material of a sufficient thickness (greater than 2 mm).

Dental Impression Materials↗
PubMed1975

[Correlations between the microstructure and the "creep" of amalgams].

For several preparations the creep behavior of amalgam which is gaining increasing clincal importance is put into relation to tested micro-structure, composition of the initial filings as well as the newly developing phase and its components. Interrelationships between the initial alloy and the gamma1-phase on the one side and the respective creep on the other were observed.

Dental Amalgam↗