Equilibrium vapor pressure of mercury from dental amalgam in vitro.
OBJECTIVE
The purpose of this study was to acquire reliable quantitative data on mercury vapor pressure above the surface of dental amalgam samples in both the as-formed and the abraded state.


METHODS
The equilibrium vapor pressure of mercury from dental amalgam was obtained using residual gas analysis in conjunction with a quartz crystal microbalance. The measurements were performed under ultrahigh-vacuum conditions.


RESULTS
Using the residual gas analyzer, the average mercury vapor pressures measured from the as-formed and abraded dental amalgam surfaces were 8 x 10(-7) and 1.7 x 10(-4) Pa, respectively. The corresponding vapor densities are: 6 x 10(-2) micrograms/m3 and 14 micrograms/m3. The average mercury vapor pressures measured from the as-formed and abraded dental amalgam surfaces using the quartz crystal microbalance were: 2.4 x 10(-6) and 1.0 x 10(-4) Pa, respectively. The corresponding vapor densities are: 0.2 microgram/m3 and 8 micrograms/m3.


CONCLUSIONS
This project provides a measurement of the equilibrium vapor pressure of mercury from as-formed and abraded amalgam surfaces. By definition, the equilibrium vapor pressure provides the maximum density of mercury which can be present in the environment above the amalgam. The vapor density of mercury within the oral cavity must be less than this value due to the dynamic nature of the system.
Wieliczka
D M
DM
Department of Physics, University of Missouri-Kansas City, USA.
Spencer
P
P
Moffitt
C E
CE
Wagner
E J
EJ
Wandera
A
A
D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003300:Copper / Q000737:chemistry; D003722:Dental Alloys / Q000737:chemistry; D003723:Dental Amalgam / Q000737:chemistry*; D005740:Gases / Q000737:chemistry; D008628:Mercury / Q000737:chemistry*; D011312:Pressure; D013499:Surface Properties; D014835:Volatilization
D003722:Dental Alloys; D005740:Gases; C033470:Dispersalloy; D003300:Copper; D003723:Dental Amalgam; D008628:Mercury