Mercury vapor from pre-capsulated dental amalgam according to storage temperature

Abstract

Aim or Purpose: The aim of this study was to measure the amount of mercury vapor from one pre-capsulated dental amalgam according to the storage temperature and to investigate whether the storage temperature suggested by the manufacturer or ISO is appropriate for the storage. Materials and Methods: GK Amalgam and Ultracaps+ were used in this study. One pre-capsulated dental amalgam was placed in a Tedlar bag and vacuumed, and the Tedlar bag was filled with 2 L of (4±2)°C air. The Tedler bag was then stored at one of the three different temperature conditions; (4±2)°C, (23±2)°C or (30±2)°C for 24 hours to obtain air containing mercury vapor. By applying Ontario hydro method, elemental mercury vapor in the Tedlar bag was oxidized in KMnO4-H2SO4 solvent and pre-treated, followed by analyses using the CVAAS method. Total of 5 measurements were obtained from each group. Results: There was a significant difference depending on the storage temperature (P<0.05), and it was confirmed that the amount of mercury vapor increased as the temperature increased. Conclusions: It was evident that storage at (23±2)°C, in compliance with the guidelines of manufacturers and ISO, result in exposure of mercury vapor exceeding 340 to 1,170 % of the exposure amount compare to the standard set by the Ministry of Labor in Korea. It is thought that the amount of mercury vapor can be reduced by lower storage temperature by methods such as refrigerating the pre-capasulated dental amalgam.