Signal standardization of the secondary ion mass spectrometry (SIMS) microscope for quantification of halogens and calcium in biological applications

Barium and strontium leaching from aged glass particle/resin matrix dental composites

OBJECTIVES

This study characterizes the loss of Ba and Sr from glass particle/resin-matrix dental composites during simulated aging.

METHODS

X-ray wavelength dispersive spectrometry and secondary ion mass spectrometry were used to analyze the Ba and Sr content from the surfaces of three commercial dental composites after aging for 4 and 8 months in humid air, artificial saliva, water, and 50% ethanol.

RESULTS

Aging in artificial saliva caused the greatest leaching of Ba or Sr for all the specimens, compared with either lesser or no leaching for aging in ethanol and water. Differences in leaching were observed between the different composites. Composites aged in artificial saliva also picked up elements in the saliva solution and displayed crystallite formation on the surface. Samples aged in ethanol displayed cracking which was not observed for water or artificial saliva.

SIGNIFICANCE

Dental composites display ion leaching from their surfaces over periods of four to eight months. Three mechanisms are proposed to explain differences in leaching for the various composites and aging solutions. Surface mineralization is also proposed to occur as a self-repair mechanism in artificial saliva.

Secondary ion mass spectrometry (SIMS) microscopy: a new tool for pharmacological studies in humans

The secondary ion mass spectrometry (SIMS) microscope has opened new fields in biological investigation because of its ability to map chemical elements that are either naturally present in tissue or introduced for diagnostic or therapeutic purposes. In this review, we will describe our attempts to localise and quantify antitumor drugs in histological sections to better evaluate successful early cancer treatment. Detection is dependent on the presence of chemical elements in the drug structure, for example halogens (F, Br, I, At) which are imaged and quantified within the nuclei. Our methodological approach combines the results obtained with ionic and photonic microscopes on serial sections. Thus, the different structures in tumor tissue (blood vessels and cells) can be identified and drug localisation visualized. Using embedded samples, we demonstrate that both fluorine (19F) in 5-Fluorouracil and iodine (127I) in 4'-iododeoxyrubicin can be mapped in human biopsy material obtained after in vivo chemotherapy.