RESUMO
<p><b>OBJECTIVE</b>To measure the magnitude of galvanic currents produced by different occluding metallic contact.</p><p><b>METHODS</b>The circuits of instantly different metallic contact were simulated in artificial saliva, and electrical potential of every couple and 15 currents of instant contact were then measured. After 8 hours' soaking, 15 currents were obtained in addition.</p><p><b>RESULTS</b>Galvanic currents variation produced hy intermittently metallic contact was ruleless. During early soaking, gold/titanium, gold/high zinc-containing amalgam and low/high zinc-containing amalgam exhibited much higher current, and there was significant difference on currents between titanium/high zinc-containing amalgam and other couples (P < 0.05). There was also significant difference on currents between titanium/high zinc containing amalgam, titanium/low zinc-containing amalgam and gold/titanium, gold/low zinc-containing amalgam and gold/high zinc-containing amalgam after 8 hours' soaking (P < 0.05). In contrast with currents produced by couples before and after 8 hours' soaking, only the currents produced by gold/high zinc-containing amalgam proved to be no significant of difference (P > 0.05), while the currents produced by gold/low zinc-containing amalgam and titanium/high zinc-containing amalgam increased. Potential of high zinc-containing amalgam was more negative than other alloys, and it was always under anodic behavior during the experiment corrupted acceleratedly.</p><p><b>CONCLUSION</b>Dentists can't ignore the case that the patient feels normal at the beginning of wearing different occluding metallic restorations. Either of gold/ titatium, gold/high zinc-containing amalgam and low/high zinc-containing amalgam appearing in oral will do harm to the patients' health. Neither of gold/low zinc-containing amalgam nor titanium/high zinc-containing amalgam can coexist in oral. Zinc-free or low zinc-containing amalgam should be selected instead of high zinc-containing amalgam.</p>