[Exposure to metals in dental laboratories]. / Esposizione a metalli nei laboratori odontotecnici.

Dental care includes handling of different types of metal alloys usually classified as "noble" and "base" in relation to the presence or absence of either gold or other precious metals. It must be born in mind that exposure to metals in this activities is due not only to those metals present in the alloys but also to those contained in the other materials used during the processes of casting and finishing. The most important metals are the following: Al, Be, Cd, Cr, Co, Cu, Au, In, Hg, Mo, Ni, Pd, Pt, Si, Ag, Sn, Ti, W, Zn. In this paper we investigated the environmental exposure to metals in dental laboratories studying the environmental air concentration of metals in casting and finishing processes estimating the "quality" of the elements present by Particle Induces X-ray Emission (PIXE) and the "quantity" of the elements by electro thermic atomic absorption spectrophotometry (ET-AAS) and the concentration of the main metals in the blood and in the urine of exposed technicians by ET-AAS. These analyses permitted to detect all the metals present in the work environment and to quantify their concentration, which always resulted to be low (except some metals during short time operations). The biological monitoring revealed the existence of moderate absorption of these metals in the exposed workers but it is not possible for us to affirm if this phenomenon represents a real risk for the health of the technicians. Hence further epidemiological and health surveillance investigations are needed to verify morbidity and mortality of the subjects employed in this activity.

PIXE technique for calcium analysis of human bone.

The determination of calcium content in human bone tissue is very useful in metabolic diseases of bone, such as renal osteodystrophy, osteoporosis, hyperparathyroidism, and osteomalacia of diverse etiology. The PIXE technique allows calcium to be directly determined in bioptic tissue sections properly, sampled for histological optical and/or electron microscopy examination.Bone semithin sections (3 µm thick, 4×4 mm(2) dimensions), cut by ultramicrotome and deposited onto polyvinyl acetate films, underwent PIXE analysis using the CISE set-up. Histomorphometric (after standard staining), evaluation of calcified bone volume (CBV) in absolute value allows calcium density to be determined. A total of nine bone biopsies were analyzed (three sections each) obtaining values ranging between 352 and 482, with an average value of 421.5±15.3 (M±SE) µg/µL, in good agreement with literature data (obtained by AAS technique on dissected bone samples).The aim of this paper is to emphasize the usefulness, of combined PIXE and histomorphometric techniques for the study of calcium content in bone tissue in both healthy and diseased bones.