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Biomedical subjects

H G Klinger

Publications and source records attributed to H G Klinger.

At least 19 recordsLinked to original sources
PubMed1991

Effect of pore topology on the remineralization rate of surface-softened enamel and synthetic hydroxyapatite: an experimental comparison and mathematical model.

Experiments with surface-softened synthetic hydroxyapatite show similar remineralization rates as surface-softened human enamel. The mineral gain with respect to time relates to parameters governing the precipitation of mineral in the specimens. A mathematical model regarding the mineral precipitation on the pore surface is fitted to the experimental values. We obtained comparable precipitation rates for apatite and tooth enamel. The geometry of the pores, however, proved to be different: a mostly tube-like pore structure must be attributed to demineralized enamel, while the synthetic hydroxyapatite specimens remineralize like a ramified, crack-like microstructure of pores.

Chi-Square Distribution↗
PubMed1990

[Retrospective evaluation and experimental radiographic study on bone reaction concomitant with orthodontic tooth movement].

Concomitant with orthodontic tooth movement a radiographically dense zone of high mineralisation can be observed on the periodontal tension side. This zone consists of the alveolar cortical bone and mineralized osteoid. This bone reaction has not evoked much interest in orthodontic literature in the past. In a retrospective study, orthopantomograms of children in orthodontic treatment were evaluated, and the discussed reaction was studied in relation with different treatment parameters. Opaque bone layers were found in cases in whom the orthopantomogram was made within 6 months after initiating tooth movement. When using elastics for tooth movement the bone reaction under discussion was comparatively rare. There is no proneness to root resorption in teeth showing the described adjacent bone reaction. Bone reaction was also studied with a densitometric radiological procedure. In all 9 cases the bone reaction was observed.

Adolescent↗
PubMed1989

[Enhancement of bite-wing radiographs by digital image processing].

Extracted premolars with an initial approximal caries were subjected to radiographic and histological examination. Radiographs were taken with the rectangular technique as used for bite-wing radiographs. Digital image processing was found to enhance the image information so that the border of caries lesions as well as histological structures, Retzius lines and Hunter Schreger stripes, within the body of the lesions were well defined. This helps to distinguish initial caries from depressions in the tooth surface.

Dental Caries↗
PubMed1989

[Digital image processing in the radiographic diagnosis of caries].

Used with x-ray films of entire teeth, digital image processing renders visible not only the contours of initial carious lesions but even histological enamel structures. In over 90% of those cases in which the lesions were deeper than one third of the enamel thickness at least the Hunter-Schreger lines were visible. This improvement in the informative value of x-ray images facilitates the therapeutic decision making process.

Dental Caries↗
PubMed1986

Enhancement of in-vivo remineralization of approximal initial caries in man by an organic and inorganic remineralization agent.

Changes of mineral content in the approximal enamel of the teeth were determined in situ with quantitative bite-wing radiography. Geometric coincidence of the base line and control radiographs was achieved with an optical adjusting device for the X-ray tube and for exact re-location of the film to the dentition. Radiographs were evaluated with digital image-processing. To five subjects, inorganic remineralization solution containing Ca, Sr, phosphate and tartrate was applied twice a day and to another 6 persons a solution containing aminofluoride (Elmex Fluid, Gaba Int.) every third day: both for 3 weeks. There was no net mineral uptake in the 15 lesions of the inorganic group but a marked increase of mineral in the 13 lesions of the other group. Discrepancy with findings of other workers may be due to the geometry of the interdental space with long diffusion distances in the dental plaque.

Adult↗
PubMed1983

Relations between heat transfer in perfused biological tissue and the local symmetry components of the vascular system.

The relation between perfusion and heat transfer in tissue can be formulated in terms of local symmetry components of the vascular system. It is shown that the order of symmetry (dipole, quadrupole etc. symmetry) gives the order of magnitude of perfusion heat transfer. A unidirectional flow component results in a D'Arcy like bulk flow. A non unidirectional flow component contributes to heat transfer at least by a second order term. It acts like an additional effective heat diffusivity. Comparison with experiments confirm the theoretical results.

Animals↗