Effect of occupational exposure to elemental mercury in the amalgam on thymulin hormone production among dental staff

2009 ◽  
Vol 25 (3) ◽  
pp. 159-167 ◽  
Author(s):  
SA Farahat ◽  
LA Rashed ◽  
NH Zawilla ◽  
SM Farouk
Keyword(s):  
Nitric Oxide ◽  
Occupational Exposure ◽  
Blood Level ◽  
Body Burden ◽  
Elemental Mercury ◽  
Mercury Vapor ◽  
Dental Amalgam ◽  
Thymus Gland ◽  
Hygiene Measures ◽  
Dental Staff

Occupational exposure of dental staff to elemental mercury vapor released from dental amalgam is an issue of concern because of the possible immunological and neurological adverse outcomes. Recently, studies have reported that inorganic mercury induces immunosuppression by decreasing the production of thymus gland hormone (thymulin). This study aimed at investigating mercury body burden in dental staff and the relation of this burden to the potential impact of mercury on thymus gland hormone level (thymulin). Besides, the work aimed at verifying mercury effect on nitric oxide synthetase as a possible mechanism of its immunotoxicity. The study population consisted of a group of dental staff ( n = 39) [21 dentists and 18 nurses] and a matched control group ( n = 42). Each individual was subjected to detailed occupational and medical history taking and to estimation of urinary mercury (U-Hg) and blood mercury (B-Hg) as indicators of mercury body burden and exposure, respectively. Measurement of total thymulin hormone blood level, and plasma level of nitrite and nitrate (indicators of nitric oxide) was also done. The study showed a significantly increased U-Hg and B-Hg levels in the dental staff compared to their controls. This elevation of mercury body burden was associated with significant reduction in thymulin hormone blood level and nitric oxide parameters. These results were more evident in the group of nurses compared to the dentists. In conclusion, our results show that dentists and dental nurses have significant exposure to mercury vapor and point to the negative impact of mercury on thymus gland functions and confirm the implication that the nitric oxide pathway is a possible mechanism for this impact. Moreover, the study raises attention to the importance of hygiene measures in reduction of exposure to mercury vapor released from dental amalgam.

Side-Effects: Mercury Contribution to Body Burden From Dental Amalgam

1992 ◽  
Vol 6 (1) ◽  
pp. 110-113 ◽  
Author(s):  
J.W. Reinhardt
Keyword(s):  
Body Burden ◽  
Elemental Mercury ◽  
Mercury Vapor ◽  
Dental Amalgam ◽  
Human Tissues ◽  
Target Organs ◽  
Highly Sensitive ◽  
Dental Amalgams ◽  
The Central Nervous System ◽  
The Relationship

The purpose of this paper is to examine and report on studies that relate mercury levels in human tissues to the presence of dental amalgams, giving special attention to autopsy studies. Until recently, there have been few published studies examining the relationship between dental amalgams and tissue mercury levels. Improved and highly sensitive tissue analysis techniques have made it possible to measure elements in the concentration range of parts per billion. The fact that mercury can be absorbed and reach toxic levels in human tissues makes any and all exposure to that element of scientific interest. Dental amalgams have long been believed to be of little significance as contributors to the overall body burden of mercury, because the elemental form of mercury is rapidly consumed in the setting reaction of the restoration. Studies showing measurable elemental mercury vapor release from dental amalgams have raised renewed concern about amalgam safety. Mercury vapor absorption occurs through the lungs, with about 80% of the inhaled vapor being absorbed by the lungs and rapidly entering the bloodstream. Following distribution by blood circulation, mercury can enter and remain in certain tissues for longer periods of time, since the half-life of excretion is prolonged. Two of the primary target organs of concern are the central nervous system and kidneys.

The Science and Politics of Dental Amalgam

1998 ◽  
Vol 14 (1) ◽  
pp. 123-134 ◽  
Author(s):  
Hellen Gelband
Keyword(s):  
Elemental Mercury ◽  
Mercury Vapor ◽  
The United States ◽  
Dental Amalgam ◽  
Mercury Exposure ◽  
Test Case ◽  
Filling Material ◽  
Science And Politics ◽  
Dental Amalgam Fillings ◽  
Amalgam Fillings

AbstractDental amalgam—a mixture of elemental mercury and a silver-dominated metal alloy—has been the most widely used dental filling material for well over a century. Alternative materials exist but are not well suited for some important applications, and all are more expensive than amalgam. The toxic effects of occupational mercury exposure have long been known, but it was not until about 1980 that serious consideration was given to the possibility that mercury vapor escaping from amalgam fillings might be affecting health, specifically producing subtle effects on the central nervous system. Such effects have been reported among dentists and other dental personnel, whose exposures are well below industrial levels but above those from fillings alone. No large studies have been completed that examine the effects of mercury exposure from dental amalgam fillings. In the face of inadequate evidence on the possible risks of dental amalgam, countries have reacted disparately. Sweden is phasing out amalgam entirely, possibly by the end of 1997. Germany has produced guidelines for limiting its use, other countries have signaled their intention to reduce it, and others—the United States and Canada—have studied the matter but taken no action. Policy differences within Europe have made dental amalgam a test case for the European Community's new medical device regulations. Relatively little epidemiologic research has been initiated to try to answer the question of dental amalgam's possible health effects. An international effort to define and carry out a research agenda to guide public policy is called for.

scholarly journals Dental amalgam risks in dental staff: systematic review

2021 ◽  
Vol 319 ◽  
pp. 01001
Author(s):  
Abdelkarim Manyani ◽  
Hanane Chaou ◽  
Naima Rhalem ◽  
Abdelmajid Soulaymani ◽  
Rachida Soulaymani Bencheikh
Keyword(s):  
Occupational Exposures ◽  
Elemental Mercury ◽  
Dental Amalgam ◽  
World Health ◽  
Nucleotide Polymorphisms ◽  
Dental Staff ◽  
Dental Amalgams ◽  
Health Organization ◽  
Dental Amalgam Fillings ◽  
Harmful Effects

Mercury is an essential constituent of dental amalgams, several studies have shown that dental personnel who work with dental amalgams are chronically exposed to mercury vapors. The World Health Organization considers that inhaling mercury vapors can have harmful effects on the nervous, immune, pulmonary and renal systems. The objective of this review was to collect and analyze data relating to the exposure of dental personnel to mercury and the possible harmful effects on human health. All biomonitoring studies published between 2002 and 2019 measuring mercury in hair, blood, urine and nails were included. Dentists reported higher levels of mercury in their biomarkers compared to control groups. These levels reflected occupational exposures to chronic low levels of elemental mercury in dental amalgam fillings. Some studies have shown a high prevalence of neurological symptoms and memory deficit in dental staff compared to controls. Studies based on genes involved in mercury metabolism have shown associations between sources of mercury exposure and single nucleotide polymorphisms in these genes. It is important that preventive measures are strengthened to reduce exposure to mercury and that a biomonitoring program for dental professionals exposed to mercury vapors is implemented.

scholarly journals Dental Amalgam and Psychosocial Status: The New England Children’s Amalgam Trial

2008 ◽  
Vol 87 (5) ◽  
pp. 470-474 ◽  
Author(s):  
D.C. Bellinger ◽  
F. Trachtenberg ◽  
A. Zhang ◽  
M. Tavares ◽  
D. Daniel ◽  
...  
Keyword(s):  
New England ◽  
Child Behavior Checklist ◽  
Elemental Mercury ◽  
Mercury Vapor ◽  
Psychosocial Outcomes ◽  
Dental Amalgam ◽  
Assessment System ◽  
Secondary Outcome ◽  
High Dose ◽  
Psychosocial Status

High-dose exposures to elemental mercury vapor cause emotional dysfunction, but it is uncertain whether the levels of exposure that result from having dental amalgam restorations do so. As part of the New England Children’s Amalgam Trial, a randomized trial involving 6- to 10-year-old children, we evaluated the hypothesis that restoration of caries using dental amalgam resulted in worse psychosocial outcomes than restoration using mercury-free composite resin. The primary outcome was the parent-completed Child Behavior Checklist. The secondary outcome was children’s self-reports using the Behavior Assessment System for Children. Children’s psychosocial status was evaluated in relation to three indices of mercury exposure: treatment assignment, surface-years of amalgam, and urinary mercury excretion. All significant associations favored the amalgam group. No evidence was found that exposure to mercury from dental amalgams was associated with adverse psychosocial outcomes over the five-year period following initial placement of amalgams.

Mercury Vapor Release from Amalgam Restorations: An In Vitro Study

2010 ◽  
Vol 1 (2) ◽  
pp. 79-84
Author(s):  
Girija Sajjan ◽  
Pradeep N Tavane ◽  
Deepak Mehta
Keyword(s):  
21St Century ◽  
In Vitro Study ◽  
Elemental Mercury ◽  
Mercury Vapor ◽  
Dental Amalgam ◽  
Practice Setting ◽  
Restorative Material ◽  
Amalgam Restorations ◽  
Elemental Mercury Vapor

ABSTRACT Dental amalgam has served as an excellent and versatile restorative material for more than 150 years despite periods of controversies. If we were to believe the opinions of some of the last decade, dental amalgam would not survive as a restorative material into the 21st century. Various forces at work seemed to doom it to extinction. The aim of the present study is to further characterize the factors that contribute to elemental mercury vapor exposure and to recommend how the practicing dentist can best minimize exposure in the practice setting.

Neonatal Mercury Vapor Exposure in an Infant Incubator

PEDIATRICS ◽  
1980 ◽  
Vol 66 (6) ◽  
pp. 988-990
Author(s):  
John F. McLaughlin ◽  
Robert W. Telzrow ◽  
Celia Mae Scott
Keyword(s):  
Newborn Infant ◽  
Body Burden ◽  
Mercury Vapor ◽  
Metallic Mercury ◽  
Heating Unit ◽  
Substantial Body ◽  
Healthy Newborn ◽  
Infant Incubator ◽  
Infant Incubators

A healthy newborn infant acquired a substantial body burden of mercury by inhaling mercury vapor originating from a broken mercury expansion switch in the heating unit of an infant incubator. Highly toxic mercury vapor is produced in quantity by heating otherwise harmless metallic mercury. Switches and thermometers that contain mercury should be removed from infant incubators.

scholarly journals Emission-dominated gas exchange of elemental mercury vapor over natural surfaces in China

2016 ◽  
Author(s):  
Xun Wang ◽  
Che-Jen Lin ◽  
Wei Yuan ◽  
Jonas Sommar ◽  
Wei Zhu ◽  
...  
Keyword(s):  
Forest Ecosystems ◽  
Agricultural Land ◽  
Mechanistic Model ◽  
Mainland China ◽  
Elemental Mercury ◽  
Mercury Vapor ◽  
Model Verification ◽  
Surface Exchange ◽  
Field Shift ◽  
Elemental Mercury Vapor

Abstract. Mercury (Hg) emission from natural surfaces plays an important role in global Hg cycling. The present estimate of global natural emission has large uncertainty and remains unverified against field data, particularly for terrestrial surfaces. In this study, a mechanistic model is developed for estimating the emission of elemental mercury vapor (Hg0) from natural surfaces in China. The development implements recent advancements in the understanding of air-soil and air-foliage exchange of Hg0 and redox chemistry in soil and on surfaces, incorporates the effects of soil characteristics and landuse changes by agricultural activities, and is examined through a systematic set of sensitivity simulations. Using meteorology simulated by the Weather Research and Forecasting Model (WRF version 3.7), the exchange of Hg0 between the atmosphere and natural surfaces in Mainland China is estimated to be 465.1 Mg yr−1, including 565.5 Mg yr−1 of emission from soils, 9.0 Mg yr−1 of emission from water body, and 100.4 Mg yr−1 uptake by vegetation. The air-surface exchange is strongly dependent on the landuse and meteorology, with 9 % of net emission from forest ecosystems, 50 % from shrubland, and savanna and grassland, 33 % from cropland, and 8 % from other landuses. Given the large agricultural land area in China, farming activities play an important role on the air-surface exchange in farmland. Particularly, rice field shift from a net sink (3.3 Mg uptake) during April to October (rice planting) to a net source when the farmland is not flooded (November-March). Summing up emissions from each landuse, more than half of the total emission occurs in summer (51 %), followed by spring (28 %), autumn (13 %) and winter (8 %). Model verification is accomplished using observational data of air-soil/air-water fluxes and Hg deposition through litterfall for forest ecosystems in China and Monte Carlo simulations. In contrast to the earlier estimate by Shetty et al. (2008) that reported large emission from vegetative surfaces using an evapotranspiration approach, the estimate in this study shows natural emissions are primarily from grassland and dry cropland. Such an emission pattern may alter the current understanding of Hg emission outflow from China as reported by Lin et al. (2010b) because of a substantial natural Hg emission occurs in West China.

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