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Biomedical subjects

J A Tesk

Publications and source records attributed to J A Tesk.

26 records · Page 2Linked to original sources
PubMed1985

Dental research at the National Bureau of Standards: how it changed the practice of dental health service.

A history of dental research at the National Bureau of Standards since its inception in 1919 is presented. The initial thrust on dental amalgam by the US Army Dental Corps, the assignment of Dr. William Souder to the project, and subsequent developments are traced. Difficulties in obtaining support for the early stages of the program following World War I are described. The involvement of the American Dental Association in 1928, issuance of the first ADA specification on dental amalgam, and the ultimate ramifications on dental (and medical) standards programs throughout the world are described. Benefits to patients, dentists, and taxpayers from support of the dental research program have been calculated as exceeding the combined budgets of the currently supporting institutions--NBS, ADA, and National Institute of Dental Research.

Chemistry, Physical↗
PubMed1983

Effects of porcelain/alloy interfacial diffusion zones on thermo-mechanical strain.

Chemical bonding between dental porcelains and alloys results from interdiffusion of porcelain and metal ions. An interfacial diffusion zone is created which, most likely, has properties different from those of bulk materials. The changed interface might affect experimental measurements of thermo-mechanical strain. To determine the magnitude and conditions under which this would occur, the interface was modeled as the intermediate layer of a three-layered porcelain-veneered split-metal ring. Layer thicknesses and coefficients of thermal expansion were varied, and the effects on gap change after cooling through 500 degrees C were calculated. Results are presented in a series of 14 Figs., ten curves each, which depict not only interfacial effects, but are extended for use in interpretation of the effects of properties of opaques and glazes as well. Under most conditions, the interface will not affect experimental measurements; some special exceptions are noted.

Chemical Phenomena↗
PubMed1981

An amine accelerator for colorfree curing of cold-curing methyl methacrylate denture systems.

These tests showed that DMBA, a recently commercialized amine accelerator, is more suitable from the standpoint of color for use in denture base, reline, and repair resins than is the commercially used amine, DMPT. As the curing times of all specimens were approximately the same, the mechanical properties are expected to be similar for the following reasons. Previous experiments have shown that in the same composite formulation, equimolar concentration of DMPT and DMBA produce identical hardening times. A more recent investigation with composite systems indicates that amines yielding comparable polymerization rates produce materials with approximately the same mechanical strength; the same is expected to prevail with unreinforced methacrylate polymers. All specimen disks provided similar resistance to bending by hand.

Chemical Phenomena↗
PubMed1976

Interaction effects among cortical bone, cancellous bone, and periodontal membrane of natural teeth and implants.

Following the initial successes of Goldberg and Gershkoff (Dental Digest, 5, 11, 1947) with the placement of subperiosteal implants, interest in all types of implants emerged. As an aid to the evaluation of various designs and materials without resorting to clinical testing, finite element analyses are being conducted by a number of researchers to determine the stress system induced in bone. The present study investigates the effects of variation in the thicknesses of the periodontal membrane and cortical bone and of the model boundary on the stresses developed around a natural tooth or a tooth-shaped implant. The results show that strong effects due to the variation in these parameters can be expected. As a consequence, the problem of the analysis of any single implant must consider additional factors. These can influence overall implant design and may eventually help to explain what could appear as anomalies in clinical test results.

Alveolar Process↗