Stability of New Amalgams with Reduced Mercury Vaporization

0613 Stability of New Amalgams with Reduced Mercury Vaporization

J.D. ADEY¹, J.L. FERRACANE¹, and T. OKABE², ¹Oregon Health & Science University, Portland, USA, ²Baylor College of Dentistry, Texas A&M University System Health Sciences Center, Dallas, TX, USA

Objective: The objective of this study was to verify the stability of amalgams that exhibit low Hg vaporization after abrasion as a result of including 1.5wt% Pd in the alloy. Methods: Amalgams (4mm dia.) (n=8), made from alloys containing 1.5% Pd with 10-14% Cu, 28.4-28.9% Sn, and 55.6-60.3% Ag were aged 1 month and 1 year. They were subsequently abraded wet on #600 SiC paper and tested for Hg release every 30-60s until reaching zero (Jerome 411). Wt.% of Sn in gamma1 and Vol. fraction of gamma1 were determined by EPMA. Total Hg release [mean(s.d.)] was determined by integration (ng/mm²/gamma1) and compared with Tytin (13% Cu; Kerr). Results: Row means with the same superscript were similar (ANOVA/Tukey's; p<.05 tested on the Log of the means).

% Cu

10

11

12

13

14

Tytin

1 Mo

7.7(3.1)

13.8(3.3)^a

16.7(6.8)^a,b

27.0(10.6)^b,c

44.1(14.7)^c

32.9(6.3)^c

1 Yr

8.8(5.9)^a

14.1(6.5)^a

13.7(2.9)^a

36.2(10.0)^b

44.4(21.0)^b

43.3(11.2)^b

Sn in the gamma1 varied from 1.14–2.09 wt% in the amalgams (1.25% in Tytin). Small amounts of gamma2 were evident in the alloys with 10% and 11% Cu. Pd significantly reduced Hg vapor emission at both time periods for alloys with less than 13% Cu, compared to Tytin. There was a significant correlation between increased Sn in gamma1 and lower Hg release (R² = 0.822 at 1Mo & 0.916 at 1Yr). All amalgams were stable with no significant difference in Hg vapor release from 1Mo to 1Yr. Conclusion: This study shows that the benefit of lower Hg vaporization from amalgams realized from the addition of only 1.5 wt% Pd to an amalgam alloy was maintained for at least one year, and should be expected to be a long-term benefit. This study was supported by NIH/NIDCR grant DE07644.

Seq #80 - Amalgam and Biocompatibility
10:15 AM-11:30 AM, Thursday, 11 March 2004 Hawaii Convention Center Exhibit Hall 1-2

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