AN ELECTROCHEMICAL STUDY BY USING A POTENTIOSTAT ON THE CORROSION OF AMALGAMS IN SALIVA

Potentiostat를 이용한 타액에서의 아말감부식에 대한 전기화학적 연구

The purpose of this study is to observe the corrosion characteristics of seven dental amalgams (CAULK FINE CUT, CAULK SPHERICAL, OPTALLOY II, DISPERSALLOY, HI VERALOY, TYTIN, VALIANT) through the anodic polarization curve obtained by using a potentiostat. After each amalgam alloy and Hg being triturated, the triturated mass was inserted into the cylindrical metal mold, and condensed by hydrolic pressure(160 kg/$cm^2$). Each specimen was removed from the metal mold. 24 hours after condensation, specimens were polished with the emery paper and stored at room temperature for 1 week. The anodic polarization curves were employed to compare the corrosion behaviours of the amalgam in 0.9% saline solution, Fusayama's artificial saliva, and stimulated parotid saliva at $37^{\circ}C$ with 3-electrode potentiostat. After the immersion of specimen in electrolyte for 1 hour, the potential scan was begun. The potential scan range was. -1700m V ~ + 400m V(vs. S. C. E) in the working electrode and the scan rate was 50m V /sec. The results were as follows, 1. The corrosion potential, the potential of anodic current peak, and transpassive potential in the stimulated parotid saliva shifted to more anodic direction than those in saline solution, and the current density in the stimulated parotid saliva was lower than that in saline solution. Those in Fusayama's artificial saliva was similar to those in stimulated parotid saliva. 2. The anodic polarization profiles in Fusayama's artificial saliva and stimulated parotid saliva indicated a region of slow slope current density, which is extending from the corrosion potential to the potential of anodic current peak, but that in 0.9% saline solution indicated no region of slow slope. 3. The corrosion potentials for CAULK FINE CUT, CAULK SPHERICAL, and OPT ALLOY II had the similarity in 0.9% saline solution, Fusayama's artificial saliva and stimulated parotid saliva, but those for high coper amalgam and VALIANT had no similarity. 4. The current density for TYTIN amalgam in stimulated parotid saliva was the lowest among the others. 5. As for current density, there was no significant difference between palladium enriched VALINAT and other high copper amalgams.