In vitro abrasion using an air-powder polishing device and its quantification by radiotracer measurement.

OBJECTIVES: This study was conducted to examine the assessment of abrasion of two different materials after neutron activation. METHODS: A fissure sealant material (Fissurit F/VOCO with a compressive strength of 235 MPa) and a glass ionomer cement (Aqua Ionofil/VOCO with a compressive strength of 170 MPa) were activated by irradiation with neutrons. Subsequent measurements of the full-energy-peak (FEP) (1368.55 keV of 24Na) were made of the sample materials before and after abrasion via exposure to the air-powder polishing to accurately describe substance loss. RESULTS: Abrasion varied more than three-fold between the two materials. SIGNIFICANCE: Neutron activation and radiotracer measurement allows the quantification of abrasion effects in different materials. In comparison with other current methods its use may allow a superior measurement accuracy and precision in determining the abraded mass.

The suitability of the iliac crest biopsy in the element analysis of bone and marrow.

Bone samples from the iliac crest were taken from 20 subjects and the content of some trace elements (iron, zinc, selenium, cobalt, strontium, aluminium, scandium, rubidium and fluorine) and of the matrix elements calcium, phosphorus and sodium was determined. The samples were taken in accordance with Burkhardt's method, which is often used in hospital for bone biopsies. The sources of errors occurring during the analysis of trace elements using this clinical procedure and the contamination of the samples by blood and the surrounding tissue are discussed. In-vivo activation analysis is also discussed as an alternative method of element analysis of the skeleton.

Non-destructive neutron activation analysis of aluminium and phosphorus in bone biopsies.

The level of aluminium and phosphorus in bone was measured by neutron activation analysis via the short lived radionuclide 28Al. The contribution of both elements to the 28Al activity could in each case by determined after the samples had been irradiated twice, once with a cadmium shield around the irradiaion position. The samples were analysed non-destructively and may later be used for further tests. Limits for the quantitative determination of aluminium and phosphorus in usual bone biopsies were calculated.

Non-destructive neutron activation analysis of copper in liver samples and other biological materials.

Neutron activation analysis via the short-lived radionuclide 66Cu was applied in the determination of the level of copper in tissues. With this procedure the samples are analysed non-destructively and can therefore be used for further histological tests. The applicability of the method in the analysis of biopsy samples is discussed.