“The potential hazards of metallic mercury in dentistry are well recognized. The present report concerns a patient who experienced an uncommonly high mercury exposure and, possibly, mercury-related toxicity from vapor released during extensive grinding of old amalgam fillings.”
“The fate of mercury (Hg) released from dental ‘silver’ amalgam tooth fillings into human mouth air is uncertain. A previous report about sheep revealed uptake routes and distribution of amalgam Hg among body tissues. The present investigation demonstrates the bodily distribution of amalgam Hg in a monkey whose dentition, diet, feeding regimen, and chewing pattern closely resemble those of humans. When amalgam fillings, which normally contain 50% Hg, are made with a tracer of radioactive 203Hg and then placed into monkey teeth, the isotope appears in high concentration in various organs and tissues within 4 wk. Whole-body images of the monkey revealed that the highest levels of Hg were located in the kidney, gastrointestinal tract, and jaw. The dental profession’s advocacy of silver amalgam as a stable tooth restorative material is not supported by these findings.”
“Dental amalgam is a major contributor to the daily nonoccupational intake of mercury. Mercury is ingested and inhaled in connection with placement, removal, and wear of restoration…”
“A thirty-year-old dental surgeon who worked until the 35th week of pregnancy in a surgery in which mercury vapour concentrations in excess of the threshold limit value (TLV) had been detected, gave birth at 42 weeks to a small-for-dates baby with severe brain damage. The possibility that this baby’s development might have been harmed by mercury is discussed and the literature relevant to teratogenicity of mercury reviewed. Attention is drawn to the need for further research into the effects on health and pregnancy outcome of mercury vapour in dental surgeries.”
“An intrauterine growth-retarded (IUGR) model based on restriction of blood supply to the rat fetus at the 17th day of pregnancy was studied. We investigated in vitro the effects of thimerosal and mercuric chloride on Na+K+ATPase activity in total brain homogenate, synaptosomes and myelin at weaning. In addition, we evaluated the reversal effect of serotonin on mercury-inhibited Na+K+ATPase activity. The toxicity, in terms of inhibition of Na+K+ATPase activity was greater with mercuric chloride than with thimerosal. Synaptosomes and principally myelin were more sensitive to the metal salts than total homogenate. Serotonin stimulated the Na+K+ATPase activity in total brain homogenate and synaptosomes but inhibited the enzyme in the myelin fraction. This effect was more marked in the IUGR group than in the control group. Serotonin (1 mM) added to total homogenate pretreated with the mercury salts produced variable reversal effects. In the synaptosomal fraction reverse effect was noted with serotonin. In myelin fraction, added serotonin increased inhibition caused by thimerosal.”
“In middle of Kii peninsula, one of the biggest mercury mine in Japan had been present until about 10 years ago. The mercury contents in water and fish are reported to be higher in this district. So we investigated the mercury in hair of patients and normal controls. In this study the subjects are 23 cases of ALS including 15 cases in Nara and Mie and 8 cases in other prefectures except in Kii peninsula, 14 cases with ataxia, 11 cases with other degenerative diseases like Parkinson’s disease and Alzheimer’s disease, 25 cases of cerebrovascular disease as compared to 26 normal controls. The hair are taken from 3 areas on head of patients and normal controls. They are washed in 2% sodium lauryl sulfate and stirred in distilled water several times, and they are soaked in acetone and dried in filter paper. They are inserted in fire and vaporized mercury are measured (Zeeman Effect Mercury Analyzer) in ppm. The hair mercury concentration is 2.81 ppm in ALS in total, 3.62 ppm in ALS in Nara and Mie and 1.39 ppm in outside of Kii Peninsula, 2.34 ppm in ataxia, 1.83 ppm in other degenerative diseases, 1.66 ppm in cerebrovascular disease and 1.44 ppm in normal controls. Statistically it is significant (p less than 0.05) between that in ALS in Nara and Mie and that in normal controls. 6 cases (40%) with ALS in Nara and Mie have the value above the mean +2 standard deviation of controls…”
“Corrosion attacks on twenty-two dental amalgam restorations after in vivo service have been studied by Scanning Electron Microscopy together with the Energy Dispersive X-Ray Technique, and by optical microscopy. From the measured depth and type of corrosion attack, estimates of released mercury amounts are made. The amalgam fillings have been obtained from members of a group of 250 individuals, who suspected their health troubles potentially to be chronic mercury poisoning from amalgam and were to have all amalgam fillings removed. Three typical patient cases are presented. Model calculations of released mercury, based on previously published measurements of corrosion currents with and without abrasion are also given. The investigations show, that the long-term release of mercury from a few amalgam fillings will often reach or exceed the recommended limits for daily intake of mercury. Hence, mercury from corroding amalgam fillings represents a potential health hazard. Danger of galvanic contact between amalgam and gold restorations is particularly emphasized.”
“Samples, mainly from occipital cortex and pituitary gland, but also from rental cortex, olfactory bulbs, thyroid gland and liver were collected from autopsies of 8 dental staff cases and 27 controls. These samples were analysed for total mercury content using radiochemical neutron activation analyses. The results revealed high mercury concentrations (median 815, range 135-4,040 micrograms Hg/kg wet weight) in pituitaries from the dental staff cases compared to controls (N = 23, median 23 range 6-1, 170 micrograms Hg/kg). In occipital cortex, the cases had a median of 17, range of 4-300 micrograms Hg/kg and the controls (N = 20) had a median of 10, range 2-29 micrograms Hg/kg. A few samples from olfactory bulbs show low mercury concentrations for both cases and controls. Renal cortex was analysed from three cases and contained clearly higher concentrations (945, 1,545, 2,110 micrograms Hg/kg) compared to controls (N = 12, median 180, range 21-810 micrograms Hg/kg). There is no control material for the other analysed samples, but one thyroid sample had an extremely high concentration of 28,000 micrograms Hg/kg.”
“The purpose of this study was to compare the relative cytotoxicity of amalgams and to determine whether their toxicity depends upon composition and aging time, by means of a rapid and sensitive in vitro cell culture test. Zinc-containing amalgams showed higher cytotoxicity than did any other amalgams. High-copper amalgams had the same cytotoxicity as did the low-copper amalgam. The addition of selenium did not reduce the cytotoxicity of amalgam. Moreover, excessive additions of selenium increased the cytotoxicity of amalgam compared with that of a similar selenium-free material. The cytotoxicity of amalgam was decreased with aging time, possibly due to the combined effects of surface oxidation and further amalgamation.”
“Mercury exposure and renal function parameters were examined in 68 dentists and 64 dental assistants. The levels of mercury in urine were low: only three individuals exceeded 20 micrograms/l. Increased excretion of urinary proteins and increased activity of urinary enzymes were observed. This enhanced prevalence of renal function changes appeared not to be related to the mercury urine level, age, sex, or smoking and drinking habits. Only for men was a positive relation between the level of mercury in urine and the activity of beta-galactosidase found. The proteinuria may be due to one or more potential nephrotoxic agents used in dental practice.”