Mercury

Before and after treatment scores on the Minnesota Multiphasic Personality Inventory – II (MMPI-II) were compared for 11 manic depression subjects with amalgams removed and for 9 subjects with amalgams who were told they were being given a placebo or sealant. Of the 87 scales, the amalgam removal group improved significantly more in 47 of them. Depression and hypomania scores improved significantly, as did anxiety, anger, schizophrenia, paranoia, and many others. Scores on the Million Clinical Multiaxial Inventory II found the scores in the amalgam removal group improved significantly more in the scales of avoidant, dependent, anitsocial and borderline, compared to the sealant / placebo group. The scores in the categories of Clinical Personality pattern category and severe Personality Pathology category also improved significantly more in the amalgam removal group. All scores of the nine dimensions tested in the Symptom Check List 90 improved significantly more in the group with amalgam removal. They included somatization, obsessive complusive, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, paranoia, and psychotism. The amalgam removal group reported a 42% decrease in the number of somatic symptoms in the placebo / sealant group when comparing a before and after health questionnaire.

“In recent years, the possible environmental impact caused by certain routines in dental practice has attracted attention among regulators. As part of point source reduction strategies, the discharge of mercury/amalgam-contaminated wastes has been regulated in a number of countries, even though it has been documented that by adopting appropriate mercury hygiene measures, including installation of amalgam-separating devices, the environmental impact of amalgam use in dentistry is minimal. There are, so far, no data indicating the environmental impact of methacrylate-based dental filling materials. As to the occupational environment, recent reports have stated that when normal occupational recommendations for proper mercury hygiene routines are followed (e.g., water spray coolant and high vacuum suction during removal of amalgam restorations), no occupational health risk can be assumed. An increasing number of reports on occupational allergic reactions to components of polymer-based dental filling materials call for attention to the sensitizing potential of certain ingredients in these products.”

“Minute amounts of mercury vapor are released from dental amalgams. Since mercury vapor is known to be associated with adverse health effects from occupationally exposed persons, questions regarding the margin of safety for exposure to mercury vapor in the general population continue to be raised. To address this issue, one needs information regarding exposure to mercury vapor from dental amalgam fillings and its possible consequences for health in the general population. The NIDR Amalgam Study is designed to obtain precise information on amalgam exposure and health outcomes for a non-occupationally-exposed population of US adults. One hypothesis was that in a generally healthy population a significant association between amalgam exposure and Hg levels in urine and/or whole blood could be detected. The cohort investigated was an adult military population of 1127 healthy males. Their average age was 52.8 years, and their ages varied from 40 to 78 years. Ninety-five percent of the study participants were white males, and slightly over 50% had some college education. Five percent were edentulous. The dentate participants, on average, had 25 natural teeth, 36.9 decayed or filled surfaces (DFS), and 19.9 surfaces exposed to amalgam, with amalgam exposure varying from 0 to 66 surfaces. Their average total and inorganic urinary mercury concentrations were 3.09 microg/L and 2.88 microg/L. The average whole-blood total and inorganic mercury concentrations were 2.55 microg/L and 0.54 microg/L. Significant correlations were detected between amalgam exposure and the total (r = 0.34, p < 0.001) and inorganic 0.34 (r = 0.34, p < 0.001) urinary mercury concentrations on the original scale. Stronger correlations were found for total (r = 0.44, p < 0.001) and inorganic (r = 0.41, p < 0.001) urinary Hg on the log scale, as well as for creatinine-corrected total (r = 0.43, p < 0.001) and inorganic (r = 0.43, p < 0.001) urine concentrations. In whole blood, statistically significant, but biologically weak, correlations were detected for total (r = 0.09, p = 0.005) and inorganic (r = 0.15, p < 0.001) Hg concentrations, respectively. Based on these cross-sectional data, it is estimated that, on average, each ten-surface increase in amalgam exposure is associated with an increase of 1 microg/L mercury in urine concentration.”

“Last weekend at an historic gathering at Wingspread, headquarters of the Johnson Foundation, scientists, philosophers, lawyers and environmental activists, reached agreement on the necessity of the Precautionary Principle in public health and environmental decision-making. The key element of the principle is that it incites us to take anticipatory action in the absence of scientific certainty. At the conclusion of the three-day conference, the diverse group issued a statement calling for government, corporations, communities and scientists to implement the “precautionary principle” in making decisions. “

“Class II resin restorations have been evolving in American dentistry for 30 years, but the concept has had significant difficulty being accepted because of stigma attached to early generations of composites. Currently available composite resins for posterior tooth restorations have physical characteristics justifying their use. Techniques for Class II resin placement have improved significantly, and mastery of them is within the ability of both dentists and dental students. Although composite resin materials and techniques present clinical challenges, so do amalgam materials and techniques. It is time to accept Class II resin restorations, improve dentist and student education about their use, increase acceptance by third-party organizations and various approving groups, and bring this concept into the mainstream of U.S. dentistry.”

This study looked at the relationship between myopia and mercury from dental fillings. Hair mercury levels were found to be significantly higher in 25 nonmyopic children compared to 25 myopic children. The researchers hypothesized that if mercury was leaching from the silver dental fillings, then subjects without dental fillings would have a higher degree of myopia and poorer acuity. A study comparing 51 subjects without amalgams confirmed this hypothesis. The non-amalgam group had a 59 percent higher degree of myopia and significantly poorer acuity. Two additional studies also found that subjects without amalgams had a higher degree of myopia. All three studies found that significantly more subjects without amalgams wore glasses for distance when compared to subjects with amalgams. The authors hypothesize that mercury may increase the collagen fibrils of the sclera and thereby retard the progression of myopia.

“Dental amalgam restorations are a significant source of mercury exposure in the human population, but their potential to cause systemic health effects is highly disputed. We examined effects on the immune system by giving genetically mercury-susceptible Brown Norway (BN) rats and mercury-resistant Lewis (LE) rats silver amalgam restorations in 4 molars of the upper jaw, causing a body burden similar to that described in human amalgam-bearers (from 250 to 375 mg amalgam/kg body weight). BN rats with amalgam restorations, compared with control rats given composite resinous restorations, developed a rapid activation of the immune system, with a maximum 12-fold increase of the plasma IgE concentration after 3 wks (p < 0.001; Mann-Whitney’s test). LE rats receiving amalgam restorations showed no significant increase of plasma IgE (p > 0.05). After 12 wks, BN rats with amalgam restorations showed significantly increased (p < 0.05) titers of immune-complex (IC) deposits in the renal glomeruli and in the vessel walls of internal organs. These rats also showed a significant (p < 0.05), from six- to 130-fold, increase in tissue mercury concentration in the concentration order kidney > spleen > cerebrum occipital lobe > cerebellum > liver > thymus, and the tissue silver concentration was significantly (p < 0.05) increased from three- to 11-fold. Amalgam-implanted BN rats showed a significant (p < 0.05) increase in copper concentration in the kidney and spleen, and in kidney selenium concentration. We conclude that dental amalgam restorations release substantial amounts of their elements, which accumulate in the organs and which, in genetically susceptible rats, give rise to activation of the immune system and systemic IC deposits.”

“Dental amalgam is the major source of inorganic mercury (Hg) exposure in the general population. The objective of the present study was to obtain data on changes in Hg levels in blood, plasma, and urine following removal of all amalgam fillings during one dental session in 12 healthy subjects. The mean number of amalgam surfaces was 18 (range, 13 to 34). Frequent blood sampling and 24-hour urine collections were performed up to 115 days after amalgam removal, and in eight subjects additional samples of plasma and urine were collected up to three years after amalgam removal. A transient increase of Hg concentrations in blood and plasma was observed within 48 hours after amalgam removal. In plasma, the peak concentrations significantly exceeded the pre-removal plasma Hg levels by, on average, 32% (1.3 nmol/L; range, 0.1 to 4.2). No increase in the urinary Hg excretion rate was apparent after amalgam removal. An exponential decline of Hg was seen in all media. Sixty days after the amalgam removal, the Hg levels in blood, plasma, and urine had declined to approximately 60% of the pre-removal levels. In seven subjects, who were followed for up to three years, the half-lives of Hg in plasma and urine were calculated. In plasma, a bi-exponential model was applied, and the half-life was estimated at median 88 days (range, 21 to 121). The kinetics of Hg in urine (nmol/24 hrs) fit a mono-exponential model with a median half-life of 46 days (range, 35 to 67). It is concluded that the process of removing amalgam fillings can have a considerable impact on Hg levels in biological fluids. After removal, there was a considerable decline in the Hg levels of blood, plasma, and urine, which slowly approached those of subjects without any history of amalgam fillings.”

“This article provides a view of government reaction in Canada to public concern over the use of dental amalgam. It also addresses the basis of the irrational fears the general public may have regarding the impact of external factors on their health.”

In 29 volunteers with a low amalgam load, the number of amalgam-covered tooth surfaces and the occlusal area of the fillings were determined. Concentrations of total mercury were measured in plasma and erythrocytes as well as in urine together with the excretion rate. Absorbed daily doses were estimated from intraoral Hg emission by two separate methods. The transfer of Hg from the fillings via the oral cavity and blood to urinary excretion was evaluated according to the most representative combination of parameters. This consisted of urinary excretion (1), Hg concentration in plasma (2), absorbed dose (3), and occlusal area (4). Pairwise correlation coefficients were 0.75 for parameters 1 vs 2 and 2 vs 3 and 0.49 for parameters 3 vs 4. Within 9 days after removal of the fillings, a transient increase was observed in plasma Hg levels only. This was reduced in those volunteers to whom a rubber dam had been applied during removal. Peak plasma Hg was 0.6 ng/ml on average and decreased with halftimes between 5 and 13 days. A significant decrease in Hg excretion was noted not before 100 days after removal. Being relatively insensitive to dietary mercury, the determination of total mercury in plasma and of its urinary excretion rate appears, under practical aspects, most suitable for the investigation of Hg uptake from amalgam.