No abstract

Recent data suggest that under certain conditions, various metal cations are released from dental alloys. These ions may produce adverse effects in various cell types in vivo. In this study, the cytopathogenic effects of 13 metal cations on murine L-929 fibroblasts, human gingival fibroblasts, and human tissue mast cells were analyzed in vitro. Several metal cations (dose range, from 0.0033 to 1.0 mmol/L) were found to induce dose-dependent inhibition of 3H-thymidine incorporation into cultured fibroblasts. The rank order of potency (lowest observed effect level, LOEL) for L-929 fibroblasts was: Ag+ > Pt4+ > Co2+ > In3+ > Ga3+ > Au3+ > Cu2+ > Ni2+ > Zn2+ > Pd2+ > Mo5+ > Sn2+ > Cr2+. A similar rank order of potency was obtained for primary human gingival fibroblasts: Pt4+ > Ag+ > Au3+ > In3+ > Ga3+ > Ni2+ > Co2+ > Zn2+ > Cu2+ > Cr2+ > Pd2+ > Mo5+ > Sn2+. In primary human mast cells, Ag+ and Au3+ caused dose-dependent toxic histamine release, whereas the other metal cations were ineffective over the dose range tested. To investigate the mechanism of metal cation-induced effects, we performed DNA as well as electron microscopic analyses on cultured fibroblasts. Both the DNA pattern and the ultrastructure of L-929 cells and gingival fibroblasts after exposure to cytopathogenic metal cations revealed signs of necrosis but no signs of apoptosis. Together, our data provide evidence that various metal cations produce dose-dependent cytopathogenic effects in distinct cell types, including human gingival fibroblasts and human tissue mast cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Palladium is increasingly used in industry, but also in fine jewelry and in dentistry. Thus, palladium-silver alloys comprise a substantial part of the noble metal ceramic alloy sales in Western countries. The increased use of this metal seems, however, to be paralleled by a rise in the number of reports of palladium allergy. Recently a European study reported a sensitization rate of 2.8%. In Austria, where palladium has started to displace amalgam in dental fillings because of concerns about mercury toxicity, and gold due to price factors, we have found a sensitization rate of 8.3% in unselected eczema patients. Despite the current lack of clear clinical relevance of this finding, these numbers should motivate us to question this substance as "the alloy of the future".

The lengths of the condylar pathways during protrusive and opening movements were investigated with computerized axiography in 100 individuals. Forty-two patients suffering from anterior disk displacement with reduction (ADD) in one or both temporomandibular joints (TMJ) and 28 patients with anterior overrotation clicking (AOC) of the TMJ were compared with 30 asymptomatic volunteers. Patients suffering from ADD showed significantly shorter tracings than did the two other groups. A significant difference of length of TMJ movement between men and women was found only in one group. The occlusal indices (OI) of the three groups were assessed and compared with each other. Here, a significant difference was found between volunteers and patients suffering ADD and between volunteers and patients with AOC. Between men and women a significant difference of the OI was found in the group with AOC, women presenting higher scores than men. Except for the group of patients with ADD, who showed shorter average lengths, volunteers as well as patients with AOC, were within the normal limits given in the literature for TMJ movement lengths recorded with axiography. The results of this examination therefore indicate that when considering movement length alone no discrimination between healthy and diseased TMJ can be made.