Mercury

“A study of 162 dentists’ and their assistants’ mercury levels in hair and urine, and of questionnaire items regarding mercury consumption, revealed some striking relations. The mercury concentrations in both hair (Hg-H) and urine (Hg-U) were somewhat higher in the dentists than the assistants. There was no relation between concentrations in hair and urine. The method of condensation of amalgam was positively related to Hg-U; the vibration method was negatively related. Hg-U was also positively related to number of fillings and hours in own practice. The relation of Hg-U to ventilation in the surgery applied only to the dentists.”

“Eighty-one women (45 dentists and 36 dental assistants) occupationally exposed to metallic mercury underwent a toxicoclinical examination. Total mercury lebels (TMLs) were determined in scalp and pubic hair by cold vapour AAS. Furthermore a detailed questionnaire study was made concerning adverse reproductive events. TMLs in the hair of the exposed women examined exceeded significantly those determined in the hair of 34 controls not exposed to mercury. All exposed women had continued working during pregnancy. There was a significant, positive association between TMLs in the hair of exposed women and the occurrence of reproductive failures in their history. The relation between TMLs in the scalp hair and the prevalence of menstrual cycle disorders was statistically significant. These findings indicate that dental work could be another occupational hazard with respect to reproductive processes.”

“Data from this project demonstrate a positive correlation between the number of occlusal surfaces of dental amalgam and mercury levels in the brain (p less than .0025 in white matter). This is indirect evidence suggesting that mercury from dental amalgam fillings may contribute to the body burden of mercury in the brain. The toxic levels of mercury in human tissues have not been sufficiently investigated and the amount of mercury in human brain tissue from dental amalgam may or may not be clinically significant. Nevertheless, dental amalgam exposure should be considered in monitoring sources of mercury accumulation in human brain tissue.”

Restorative alloys with a high percentage of nickel are relatively new to the field of fixed prosthodontics. These alloys have gained favor because of their strength and low cost. Since 1970, the use of these alloys has climbed from small usage to 32’70 to 80’70 of the restorations in the United States.  Clinically, these alloys appear to perform as well as the gold based alloys. Although the problems with base metal alloys seem to be minor, there are concerns that longitudinal and epidemiologic studies may show biocompatibility problems in patient sensitivity, and carcinogenicity in the laboratory technician and dentist.

For approximately 150 years, mercury in amalgam has been used as a dental restorative material. Throughout this time the potential toxicity of this metal to patients (1-5) and dental professionals (4-9) has been studied and debated. In these reports and many others, problems with mercury contamination and toxicity were uncovered. Although the extent of the problems may be controversial, the overall impact has led to increased emphasis on mercury hygiene in dental schools and in private practice (10-11).”

Not available.

“Mercury accumulation in brain, kidney, liver and heart following insertion of amalgam in the teeth of guinea-pigs has been studied. During the accelerated wear of the amalgam in these gnawing animals, a significant mercury accumulation in the above tissues was demonstrated. Finely diffused and abraded amalgam must not be ignored as a source of absorbable mercury.”

“Samples from the central nervous system (occipital lobe cortex, cerebellar cortex and ganglia semilunare) and kidney cortex were collected from autopsies and analysed for total mercury content using neutron activation analyses. Results from 34 individuals showed a statistically significant regression between the number of tooth surfaces containing amalgam and concentration of mercury in the occipital lobe cortex (mean 10.9, range 2.4-28.7 ng Hg/g wet weight). The regression equation y = 7.2 + 0.24x has a 95% confidence interval for the regression coefficient of 0.11-0.37. In 9 cases with suspected alcohol abuse mercury levels in the occipital lobe were, in most cases, somewhat lower than expected based on the regression line. The observations may be explained by an inhibition of oxidation of mercury vapour. The regression between amalgams and mercury levels remained after exclusion of these cases. The kidney cortex from 7 amalgam carriers (mean 433, range 48-810 ng Hg/g wet weight) showed on average a significantly higher mercury level than those of 5 amalgam-free individuals (mean 49, range 21-105 ng Hg/g wet weight). In 6 cases analysis of both inorganic and total mercury was carried out. A high proportion (mean 77% SD 17%) of inorganic mercury was found. It is concluded that the cause of the association between amalgam load and accumulation of mercury in tissues is the release of mercury vapour from amalgam fillings.”

“In 52 patients with oral lichen planus topographically related to amalgam restorations, the fillings were replaced by other materials in 18, 16 of whom experienced complete remission of the lesions within 1-12 months. These results are discussed in relation to the results of epicutaneous patch tests for possible allergy to a number of mercury compounds. The term ‘oral lichenoid reaction’, is suggested to describe these lesions.”