IN-VITRO CYTOTOXICITY OF AMALGAMS MADE WITH BINARY HG-IN LIQUID ALLOYS

Objective. Mercury vapor release from amalgams during setting signific antly decreases when the amalgams are prepared with binary Hg-ln liqui d alloys. The objective of this study was to compare the cytotoxicity of amalgams made with experimental Hg-ln alloys with that of amalgam w ithout In and a commercial In-containing amalgam. Methods. Amalgam spe cimens were prepared by triturating a high-Cu alloy powder (Tytin, Ker r) with pure Hg or Hg-ln liquid alloy containing 5, 20 or 50% In and a lso by triturating an In-containing high-copper alloy powder (Indiloy, Shofu) with pure Hg. After the specimens were aged for 2 wk, a cylind rical specimen of each amalgam was immersed consecutively in cell cult ure medium for 0-8, 8-48 and 48-72 h. The cytotoxicity of the extracts was determined by placing them in contact with Balb/c 3T3 mouse fibro blasts for 24 h, after which the succinic dehydrogenase (SDH) activity was measured and expressed as a percentage of the Teflon negative con trols. The results were statistically compared using ANOVA and Tukey's test (alpha = 0.05). The concentration of elements released into the extracts was determined by atomic absorption spectrophotometry and eva luated by Kruskal-Wallis and nonparametric multiple comparisons. Resul ts. For the 0-8 h and 8-48 h intervals, the 20% In amalgam was signifi cantly (p < 0.05) less toxic than the other amalgams, and not differen t from the Teflon control. Results for the other amalgams were only sl ightly depressed compared to the Teflon control. For the 48-72 h inter val, all amalgams were essentially no different from the control. Copp er was the element dominantly released into the medium from all the am algams tested. Significance. For amalgam tested after aging, alloying indium to mercury did not deleteriously affect the cytotoxicity of the resultant amalgam compared to the amalgam without indium.