ABSTRACT
It is well-known that bone volume decreases with age both in normal subjects and particularly in osteoporotic patients. It is not well demonstrated, however, whether bone loss is associated with changes in the composition of bone tissue and especially with altered concentration of mineral elements. To verify whether calcium density changes with aging, autoptic specimens, of iliac crest trabecular bone from 20 normal subjects between 21 and 66 years, 10 males and 10 females were analyzed by using a new method which allows the measurement of calcium density in a non-destructive way, on entire histologic sections of the bone. Bone specimens were embedded in araidite and tissue sections, about 3 microm thick and 4x4 mm size, were mounted onto polyvinyl acetate films and analyzed by PIXE (proton induced X-ray emission) using the CISE setup for calcium content determination. The same bone tissue sections were then mounted on glass slides, stained with the Von Kossa method and the volume of calcified bone was measured with a semiautomatic image analyzer (Videoplan). 3 to 4 sections from each subject were analyzed and the values of calcium concentration were derived in microg/microl. Similar values of calcium density were found in males and females (535.6+77.1 and 539.2+74.1 microg/microl, respectively). No significant correlation between calcium density and age was observed either in all cases (r=0.0925) or in males (r=-0.0687) and in females (r=0.2676) separately. The unchanged calcium density during aging obtained by combining PIXE and histomorphometric techniques demonstrates that the skeletal calcium reduction observed in old age and probably during osteoporosis, is mainly due to the decrease of bone volume.
ABSTRACT
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.
