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Methods: Ten upper custom-made night-guards were fabricated for patients suffering from bruxism, who had amalgam-restorations in their upper molars. The night-guards were delivered to the patients and they were instructed to wear the night-guards during when they were asleep. After six months, the night-guards were taken from the patients to be analyzed. A new unused night-guard was fabricated from the same material to be used as a control. In the used night-guards, two areas were studied: the fitting surfaces contacting the amalgam restorations and the fitting surfaces not contacting amalgam restorations. Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Analysis (EDXA) were used to examine the structural and elemental changes in the night-guards.
Results: SEM of the unused night-guard revealed a homogenous structure, and the composition was carbon and oxygen, as shown using EDXA
(C=88.9wt% and O=11.1wt%). By contrast, the fitting surfaces of the
night-guards contacting amalgam restorations showed numerous lustrous particles. Elemental analysis of these areas showed the presence of mercury and sulfur, in addition to carbon and oxygen (Hg=21.2wt%, S=2.5wt%,
C=67.1wt% and O=9.2wt%). The night-guards’ fitting surfaces not contacting amalgam restorations showed slight cracking, and the composition was carbon and oxygen (C=88.3wt% and O=11.7 wt%).
Conclusions: Analyzing fitting surfaces of night-guards contacting dental restorations, such as amalgam, could aid in understanding the nature of leached-elements from these restorations intra-orally. However, further studies about its application upon dental-restorations other than amalgam are recommended.

Conclusions: During amalgam removal, mercurial vapor increases in the dental office. So, as shown by several stud-ies, the dentists using amalgam and their staff members are exposed to chronic mercurial intoxication.

Background:This study evaluated Thimerosal-containing childhood vaccines and the risk of a diagnosis called disturbance of emotions specific to childhood and adolescence (ED). Thimerosal is an organic-mercury (Hg)-containing compound used in some vaccines.

Methods: A hypothesis-testing prospective, longitudinal case-control study evaluated Hg exposure from Thimerosal in hepatitis B vaccines administered at specific times within the first 6 months of life and its association with medically diagnosed ED (313.xx) (n = 517) in children born between 1991–2000 in comparison to controls (n = 27 491) in the Vaccine Safety Datalink (VSD) database.

Results: Cases diagnosed with ED were significantly more likely than controls to have received increased Hg exposure within the first month of life (odds ratio (OR) = 1.3384), the first 2 months of life (OR = 1.3367) and the first 6 months of life (OR = 2.37). When the data were separated by gender, similar significant adverse effects were observed for males, but not females. On a per microgram Hg basis, cases diagnosed with ED were significantly more likely than controls to have received increased exposure within the first 6 months of life (OR = 1.025 per microgram Hg).

Conclusions: The results show a significant relationship between Hg exposure from Thimerosal-containing childhood vaccines and the subsequent risk of an ED diagnosis.

Methods
Kidney cortex biopsies and urine and blood samples were collected from 109 living kidney donors. Total Hg concentrations were determined and the relationships between K-Hg, U-Hg, P-Hg, and B-Hg were investigated in regression models. The half-time of K-Hg was estimated from the elimination constant.

Results
There were strong associations between K-Hg and all measures of U-Hg and P-Hg (rp = 0.65–0.84, p < 0.001), while the association with B-Hg was weaker (rp = 0.29, p = 0.002). Mean ratios between K-Hg (in μg/g) and U-Hg/24h (in μg) and B-Hg (in μg/L) were 0.22 and 0.19 respectively. Estimates of the biological half-time varied between 30 and 92 days, with significantly slower elimination in women. Adjusting overnight urine samples for dilution using urinary creatinine resulted in less bias in relation to K-Hg or U-Hg/24h, compared with other adjustment techniques.

Conclusions
The relationship between K-Hg and U-Hg is approximately linear. K-Hg can be estimated using U-Hg and gender. Women have longer half-time of Hg in kidney compared to men. Adjusting overnight urine samples for creatinine concentration resulted in less bias.”

This study focused on the evaluation of the levels of total mercury in hair among 120 breastfeeding mothers aged 20 to 45 -. The concentrations of Hg ranged from 0.07 to 6.87 μg/g with a geometric mean (GM) of 1.22 μg/g. This GM is six times higher than the average internal exposure of mothers from other 17 European countries (0.225 μg/g). Near 70% of mothers presented levels of Hg above the USA EPA internal exposure guideline of 1 μg/g, and 27% exceeded the EFSA health-based guidance value of 1.9 μg/g. The multivariate regression analysis revealed that age, smoking and fish consumption (sword fish, small fat fish, small lean fish) were the major predictors of mercury in hair.

The research conducted on humans in this area is diverse in study design and the results are conflicting. There is currently no evidence to implicate a role for Hg0 exposure from dental amalgams in the development or perpetuation of autoimmune disease, apart from some suggestion of individual sensitivity. Several studies have consistently shown a positive correlation between iHg exposure and serum autoantibody concentrations in gold miners, although the clinical impact of iHg remains unknown. Furthermore, a limited number of studies have reported individuals with autoimmune disease have higher concentrations of blood Hg compared to healthy controls. In summary, it appears that iHg perpetuates markers of autoimmunity to a greater extent than oHg, albeit the impact on clinical outcomes in humans is yet to be elucidated.