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Biomedical subjects

E Lenz

Publications and source records attributed to E Lenz.

At least 73 records · Page 4Linked to original sources
PubMed1979

[Studies on the proper processing of silver-palladium casting alloys].

The internal structure and the hardness of three silver-palladium alloys (Sipal 306, Spall WT 52, Bego Gold-EWL G) were investigated in the as-cast condition, after homogenization and after salt-bath hardening. From the results obtained it is concluded that the optimal processing conditions for Sipal 306 and Spall WT 52 are: homogenization at 850 degrees C for more than 2 hours, and hardening at 430--450 degrees C for 15 minutes. The hardness values thus obtained meet the requirements of the type IV indication of the FDI specification no. 7; however, the inhomogenous structure causes a lower resistance to tarnish.

Dental Alloys↗
PubMed1978

[Studies on the setting behavior of dental gypsum. 1. Experimental characterization of the hardening process].

Using penetration tests, the authors studied the setting of dental gypsums (alpha- and beta-hemihydrate) under different conditions of processing (temperature of the mixing water, mixing time, addition of electrolytes). The suitability of penetrometry as a standardizable testing procedure for characterizing the setting process of gypsums is demonstrated and the effects of different materials and processing parameters on setting are discussed.

Crystallization↗
PubMed1978

[Bridge abutments and bridge anchors--functional, technological and methodological aspects].

The fixed partial prostheses form a functional unity together with the abutment teeth and the periodontium. They must be kind to these tissues and protect them effectually. With regard to these goals, the author outlines the choice of abutment teeth and the shaping of the anchors as well as the use of materials and techniques in the light of anatomical, physiological and material-specific findings.

Biomechanical Phenomena↗
PubMed1977

[Technological bases for rational impression technics for fixed partial dentures].

Starting from the general properties of silicone-elastomer impression materials, the author outlines problems concerning their adequate processing. He deals in particular with studies on the mixing time, the value of the change in shape and the dimensional behaviour of "Stafanat zähplastisch" and "Stafanat leichtfliessend" that demonstrate the effects of different working conditions.

Dental Impression Technique↗
PubMed1976

[Technological studies on high pressure polymerization of dental plastic materials].

The author in his present paper reports a program of comparative materials testing of which the purpose was to assess the value of positive pressure polymerization of thermosets. This particular program required polymerization temperature measurements. K-value determinations, and cone indentation hardness tests to be made on samples of plastic material polymerized under positive liquid or steam pressure and in cuvets, respectively, the conditions of polymerization being those which are used in actual practice. The results obtained indicated a favorable influence of positive liquid pressure polymerization on the final hardness of the plastic material.

Dental Materials↗
PubMed1975

[Material-testing studies for the rationalization of the technology of stomatological cold curing-plastics].

Materials scientific studies on the rationalization of the processing of stomatological cold-curing plastics. Hydropneumatic overpressure polymerization leads to a considerable rationalization of the processing of stomatological cold-curing plastics, but its effects on the course of polymerization and the properties of the polymerizate are yet not sufficiently elucidated. For this reason, the author studied in several test series the effects of various processing parameters (flask and overpressure vessel; varying mixing ratios, pressures and temperatures) on the polymerization of Kallocryl-AS, a cold-curing plastic. The results obtained indicate that, under certain processing conditions, overpressure polymerization of cold-curing plastics may be recommended from the viewpoint of materials science.

Cold Temperature↗