Author: Jones DW.
Source: J Can Dent Assoc.
Year: 1999
Comment:
The author suggests that an individual would need 490 surfaces to exceed guidelines of mercury vapor levels. The author also suggests that "Given the epidemiological evidence we have, it seems likely that humans may have evolved with a threshold level for mercury below which there is no response or observable adverse health effects." Additionally, the author does not report on genetic factors or allergic reactions.
Abstract / Excerpt:
“Health Canada recently lowered the recommended maximum daily exposure of mercury from all sources for women of child-bearing age and for children less than 10 years. This new exposure guideline does not seem to be based on any new scientific finding of human toxicity. The average daily intake of methylmercury (mainly from fish) that may cause demonstrable health effects in the most sensitive individual is 300 micrograms/day, or 4.3 micrograms Hg/day/kg body weight. The new, lower Health Canada limit is 95% below the level that may cause health effects. A number of studies have looked at methylmercury in human breast milk (where maternal consumption of fish is high), but no strong evidence of toxicity has been reported. The amount of mercury released from dental amalgam is minimal; a person would have to have 490 amalgam surfaces for there to be enough mercury vapour and ionic mercury given off from amalgam fillings to meet the maximum exposure guidelines. The uptake of food-related organic mercury is six times higher than the uptake of mercury from amalgam; moreover, food-related mercury is significantly more toxic. Many studies of amalgam-related mercury are flawed by confusion between exposure and absorption for the various forms of mercury, a limited selection of data, the ignoring of confounding variables or the misclassification of data.”
Citation:
Jones DW. Exposure or absorption and the crucial question of limits for mercury. J Can Dent Assoc. 1999; 65(1):42-6.