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Biomedical subjects

H G Klinger

Publications and source records attributed to H G Klinger.

33 records · Page 2Linked to original sources
PubMed1980

[Mechanical properties and acid solubility of the dental surface. I. Microhardness].

The present paper deals with the relationship between microhardness, and the circumferential as well as radial location of the test points on the tooth surface. The measurements did not indicate a significant correlation between the average hardness of the tooth sections, and their location on the circumference. The average hardness of the sections on one probe, however, showed a large variation. Hardness was also correlated with the distance from the enamel surface. There was a steep hardness gradient in the outermost 50 micrometer thick enamel layer: hardness increased in the direction to the dentino-enamel junction. The investigated enamel layer seems to be layer of less mineralized enamel which might have its origin in de-, and remineralization processes on the enamel surfaces.

Bicuspid↗
PubMed1979

The mimimum inactivated cell ratio: a concept for the estimation of biological effectiveness of hyperthermic treatment of tissue.

The experimental conditions used to investigate the dose-effect relationships for hyperthermic treatment of cells in vitro cannot be realized in vivo. Thus it is not possible to predict the cell inactivation due to a hyperthermic treatment of the tissue in vivo, using the in vitro dose-effect-relationships. However, the in vitro dose-effect curves in combination with the temperature field in vivo make it possible to calculate the lower limit of the biological effect, the minimum inactivated cell ratio (MIR). This magnitude is of clinical relevance. The present paper gives the algorithm for the calculation of the MIR, and discusses the influence of the heat supply time on the local biological effect for a model with spherical symmetry.

Cell Survival↗
PubMed1979

[Comparative studies of the hardness of dental calculus after the use of 2 dentifrices].

A method was described for recording the mechanical characteristics of tartar using objectively comparable test data. This method was used to study tartar which had formed when different tooth pastes were used. The results of this study indicate that 1. Tartar formed when different tooth pastes are used may exhibit different characteristics; 2. The dynamic measurement of indentation is suitable for quantitative determination of the mechanical characteristics of tartar. These mechanical characteristics have not been ascertainable until now.

Biomechanical Phenomena↗
PubMed1978

[Spatial variations of the mechanical properties of dental enamel and dentin].

Cuts with a Vickers diamond were made in five horizontal planes of the upper third of the crown of human lower premolars. At the same time the depth of entry was registered directly during the cutting with adot screen with a distance of about 150 mu between the dots. The depth of the cuts obtained was determined by optical measurement of breadth. Only in the fissure enamel was a slight hardening in the cervical direction observed. With a 5 p loading of the cutter diamond the reversible (elastic) deformation in the dentine is 0,4 +/- 0,1 micrometer greater than in the enamel. The optically determined cutting depth (irreversible deformation) amounted to 1,2 +/- 0,1 micrometer or 2,1 +/- 0,2 micrometer in enamel and dentine.

Bicuspid↗
PubMed1978

[Determination of the surface topography of etched dental surfaces].

Klinger and Gabriel recently described a method for the determination of surface topography in which the surface is probed by a mechano-electrical movable handle attached to defined line-scanner pattern. The evaluation of the "surface topogram" thus obtained is elucidated with the aid of a surface topogram of a straight fissure. A contour map is drawn with the help of this surface topogram for an area of about 300 micron X 500 micron of a cauterized surface in the enamel of a transverse cut. This shows that broad cauterization structures occur not only in the enamel near the dentine but also in the area of outer enamel which is caused by differential dehiscence or splitting of enamel prisms with different orientation towards the cut surface.

Acid Etching, Dental↗
PubMed1977

[The determination of mechanical properties of hard tissue surfaces in microareas by means of mechano-electrical methods].

The resistance of surfaces of hard tissue against chemical attacks e.g. acids can be measured with high spacial specifity by electro-mechanical registration of surface topograms. Apart from this property of hard substance, important in connection with the development of caries, the sample principle of measurement can be used in vitro on dental surfaces to obtain other important measurements. Examples are given to show how the hardness is determined by the summation of elastic and plastic properties. It is shown how far during the usual measurements for hardness of impressions the duration of the process and the time elapsed before measurement can influence the results.

Acids↗
PubMed1976

[The variation of the depth of the cervices in the ground surface of the tooth].

Variations in the depth of scratches in a transverse section of a premolar was studied. The scratches were produced by a Vickers diamond whose vertical deviations during scratching were measured by an inductive distance recorder and continually registered by an xy-recorder. The depth of scratches in all areas of the enamel was almost constant with only minimal variation. In the dentine, too, the variations were small, the constant being greater than in the enamel. The greatest depth was measured in interglobular dentine.

Bicuspid↗