Determination of the Rate of Release of Intra-oral Mercury Vapor from Amalgam

Abstract

The experimental and analytical difficulties associated with the measurement of mercury vapor in the oral cavity are considerable. In the present paper, the objective was to measure the amount of intra-oral mercury vapor in subjects with amalgams, by means of two sets of equipment based on different functional principles. In addition, it was found that the type of mercury source prevalent in the oral cavity had to be evaluated. The measuring technique used to obtain correct results is discussed, and an evaluation of the conditions for the application of the measuring equipment available was made. It was found that the amount of mercury released from the oral cavity was time-dependent. Furthermore, the amount of mercury released with the time kept constant was almost independent of the pumping flow rate up to 8 L/min. It was found that the tissue, saliva, and the amalgam restorations were not depleted of mercury during the measuring time. The results of the Mercollector-Mercometer measurements carried out on seven subjects with nine or more occlusal surfaces restored with dental amalgam and on three subjects without any amalgam restorations revealed that the rate of mercury release was in the range 0.03-0.34 ng/sec in the former group and less than 0.01 ng/sec in the latter. Based on the experimental results and on theoretical considerations, it was concluded that the amount of mercury released per time unit is the only quantity measurable.

Gaseous Elemental Mercury and Total and Leached Mercury in Building Materials from the Former Hg-Mining Area of Abbadia San Salvatore (Central Italy)

“…Prolonged exposure to mercury vapor may induce neurological dysfunction and even low-level exposures are reported to produce weakness, anorexia, weight loss and so forth [56]. Changes in personality, loss of memory, depression and occasionally delirium were reported as some of the symptoms when man is exposed to high-level of mercury vapor [57]. [32] evidenced that miners of Abbadia San Salvatore did not suffer exposure to Hg° since no native mercury was present in the ore deposit.…”

Mercury Exposure From Dental Amalgam Fillings: Absorbed Dose and the Potential for Adverse Health Effects

“…In interpreting each subject's intra-oral mercury vapor readings, however, Vimy and Lorscheider treated the measurements as though the subject were exposed to room air at those concentrations. Several authors have pointed out their error (Mackert, 1987;Olsson and Bergman, 1987;Berglund et al, 1988;Clarkson et al, 1988). In the paper by Berglund et al (1988), it was shown experimentally that the mercury vapor release from amalgams was a time-dependent process and that the amount of mercury released during a certain time period was independent of the flow rate of the air through the oral cavity during respiration and collection with measuring instruments.…”

“…In the discussion of ingestion of particulate amalgam, it should be noted that the gastrointestinal absorption of elemental (metallic) mercury is extremely lowon the order of 0.01% (Williams, 1981;Tsalev and Zaprianov, 1983 Two separate investigations (Berglund et al, 1988;Clarkson et al, 1988) have shown that mercury vapor does not continue to build up in the mouth during respiration through the nose. In the study by Berglund (1990), it was calculated that about 75% of the vaporized mercury is dissolved in the saliva and swallowed (the model predicts that 12.5% is inhaled, 12.5% is exhaled, and 75% is swallowed).…”

The effect of hydrogen peroxide concentration on metal ion release from dental amalgam

“…This lack of standardisation is reflected in the large variation in their reported data which in turn may also explain the very different conclusions reached by some authors. 18,19 Several bleaching methods exist, including in office bleaching with or without a light source, 20,21 mouth guard bleaching under supervision of a dentist, and bleaching kits that are sold over the counter (where individuals apply the bleaching agent without the supervision of the dentist). We reported previously on metal ion release from dental amalgam following exposure to CP at a single concentration.…”