Vaporization of Hg from Hg-In amalgams during setting and after abrasion

Objective: The aim of this study was to determine if Hg vaporization during setting and after abrasion of amalgams could be reduced by adding indium to Hg prior to trituration. Methods and materials: Hg-In alloys (0,5,10,15 wt% In) were triturated with commercial amalgam alloys (Tytin, Kerr; Artalloy, Degussa; Sybraloy, Kerr) and condensed into cylinders (4 × 8 mm). In one experiment, Hg release during setting was measured in air (37°C) with a Jerome 431 Hg analyzer (n = 4). In a second experiment, amalgams aged two months were uniformly abraded on wet #600 SiC, blotted dry, and Hg release was measured in air (22°C) for 30 min with a Jerome 411 Hg analyzer (n = 6). Total Hg was determined by integration (ng/mm²). Results were compared by ANOVA and Tukey's test (α = 0.05). Results: Indium reduced Hg release from amalgams during setting. Amalgams ceased Hg release within 5 h. Indium did not reduce Hg release from abraded, set amalgams except Artalloy w/15% In. Significance: Coupled with our previous studies, this work shows that 5-15 wt% indium can be added to effectively reduce Hg release during setting, but not after abrasion of set amalgams.