“Dental amalgam (or ‘silver-colored filling’) is a durable metal alloy comprised of silver, copper and tin, in addition to mercury, which binds these components into a hard, stable substance. It has been used to safely restore the teeth of more than 100 million Americans.”
“Now the American Dental Association, what they tend to do is they hire a dentist to do a study, and they kind of let them know how they want the study to come out.”
The statement "We will by the end of the year, we will make an announcement" is made in this video by FDA Center Director Jeff Shuren on dental amalgam on September 22, 2011, and it can be viewed at 3:14 in the video.
“BACKGROUND: This study was undertaken to determine the effect of thimerosal on the neurodevelopment of premature rats.
METHODS:
Thimerosal was injected into premature SD rats at a dose of 32.8, 65.6, 98.4 or 131.2 ?g/kg on postnatal day 1. Expression of dopamine D4 receptor (DRD4) and serotonin 2A receptor (5-HT2AR), apoptosis in the prefrontal cortex on post-injection day 49, and learning and memory function were studied and compared with those in a control group injected with saline.
RESULTS:
Expression of DRD4 and 5-HT2AR and learning function decreased, and apoptosis increased significantly in the 131.2 ?g/kg group (P<0.001). Memory function was significantly impaired by 65.6 (P<0.05), 98.4 and 131.2 ?g/kg (P<0.001).
CONCLUSIONS:
The negative adverse consequences on neurodevelopment observed in the present study are consistent with previous studies; this study raised serious concerns about adverse neurodevelopmental disorder such as autism in humans following the ongoing worldwide routine administration of thimerosalcontaining vaccines to infants.”
Objectives
We have investigated the effects of X-rays and magnetic resonance imaging (MRI) on the release of mercury from dental amalgam into artificial saliva.
Methods
A commercial brand of amalgam capsules was used, and the capsules were molded into discs (diameter 3 mm, thickness 1 mm) in plexiglas molds before treatment. The samples were divided into three groups. The first group was exposed to X-rays, the second group was exposed to MRI in a soft tissue-equivalent material, and the third group contained an equal number of samples as a control group. All samples were stored in artificial saliva for 1, 2, or 24 h. Mercury analyses were performed with a cold vapor atomic absorption spectrometer. The results were analyzed by two-way repeated-measures analysis of variance with the Bonferroni correction as a post hoc test at the 95 % confidence level.
Results
A significant increase in mercury was detected in the X-ray-exposed group versus the control group (mean values 5.79 vs. 3.84 ppb, respectively; p ≤ 0.05). However, no significant difference in mercury dissolution was found between the MRI-exposed group and the control group (mean values: 4.51 vs. 4.30 ppb).
Conclusions
Mercury release increased after exposure to X-rays, but no change was detected after exposure to MRI.
The rules governing the use of metallic mercury, a toxic and hazardous chemical, is in most jurisdictions identical to widely accepted standards and practices for handling the same chemical in industry for the protection of humans and their work environment. There cannot be exceptions solely for the practitioner dentists and their patients. Any workplace must be safe for both workers and visitors. The latter being dental patients waiting in the dentist’s work environment. We reviewed the literature for toxic health effects of elemental mercury upon humans and present information about the Minimata Convention convened by the United Nations Environment Programme. A study conducted among dentists in Singapore and their personal work environment almost 30 years ago contributed to the workplace standard for elemental mercury, which was reduced, and is still currently enforced as a global standard. We recommend that dentists, with a large alternative battery of restorative materials today, make selection of a restorative material a more seriously considered choice, and not to make use of amalgam without the proper use of personal protective equipment for themselves (members of the dental operating team) and their patients, (amalgam traps and judicious monitoring of their workplace air quality). Mercury is ubiquitous in our presence due to human activities; any reduction in the dentists’ workplace contributes to a global reduction.
Amalgam use in dentistry has been controversial since around the 1830’s, in part because it threatened the profitable use of gold as a filling material, but also because of health concerns about mercury.
Substance Flow Analysis (SFA) is an approach showing main sources of emission and flows of pollution to the environment, which allows to define possible environmental risk. Total identified mercury emission to air, soil and water in Poland for year 2010 from anthropogenic sources was estimated as 18.0 Mg. Annual Hg emission to air from by-product sources was equal 13.5 Mg, with the highest share of emission from brown coal-fired power plants. Mercury contained in combustion residues and removed from flue gases is transferred to waste waters, disposed to landfills and used to a concrete production with unknown amounts. Annual mercury emission to air from the use of mercury-containing products (0.5 Mg) was estimated by authors based on model for distribution and emissions for batteries, light sources, other electrical and electronic equipment and also for measuring and control equipment. Emission to air from dental practice (0.3 Mg) was estimated for combustion of wastes containing dental amalgam and from bodies cremation. SFA for the use of mercury-containing products and dental practice presents significant load of 10.4 Mg mercury
contained in hazardous wastes produced annually. It covers wastes of used products, dental amalgam wastes directly from clinics as well as stream from incineration of infectious dental wastes. In the paper mercury discharges to water from large and medium industrial facilities (2.9 Mg) and municipal waste-water treatment plants in large agglomerations (0.4 Mg) are presented. Smaller loads are generates by leachate transfer from
municipal landfills to WWTPs and further to agriculture and also by releases from dental amalgam in buried bodies. The paper indicates lack of information in SFA which should be regarded, mainly concerning mercury releases from municipal landfills to water and soil and emissions from municipal WWTPs to air.
“The Minamata Convention, a global legally binding instrument (treaty) on mercury, has been the catalyst for the emerging agenda on global dental materials research. If the current and future challenges of oral health maintenance and healing on a global scale are to be met, a logical and effective research agenda for the discovery and introduction of new, environmentally sustainable, dental materials must be developed through a coordinated effort involving materials scientists, dental clinicians, representatives of industry, members of regional and national regulatory bodies, and advocacy from research organizations. For universal impact, this agenda should be created with awareness of several important ongoing initiatives, such as the WHO non-communicable diseases action plan, the UN sustainable development agenda, and the IADR Global Oral Health In Inequalities Research Agenda (GOHIRA). A significant contributor to this cause is the FDI and its membership, who, through their Vision 2020 initiative, acknowledge their role and responsibility in globally preventing and managing dental disease and providing leadership to the profession in terms of information dissemination and affecting change. Dental researchers also have an obligation to advocate for appropriate funding to match the identified research needs, thus enhancing the possibility that key decision-makers will provide the needed support to achieve the research agenda agreed upon by this diverse group of stakeholders.”
“BACKGROUND:
Cognitive consequences at school age associated with prenatal methylmercury (MeHg) exposure may need to take into account nutritional and sociodemographic cofactors as well as relevant genetic polymorphisms.
METHODS:
A subsample (n = 1,311) of the Avon Longitudinal Study of Parents and Children (Bristol, UK) was selected, and mercury (Hg) concentrations were measured in freeze-dried umbilical cord tissue as a measure of MeHg exposure. A total of 1135 children had available data on 247 single-nucleotide polymorphisms (SNPs) within relevant genes, as well as the Wechsler Intelligence Scale for Children Intelligence Quotient (IQ) scores at age 8 years. Multivariate regression models were used to assess the associations between MeHg exposure and IQ and to determine possible gene-environment interactions.
RESULTS:
Hg concentrations indicated low background exposures (mean = 26 ng/g, standard deviation = 13). Log10-transformed Hg was positively associated with IQ, which attenuated after adjustment for nutritional and sociodemographic cofactors. In stratified analyses, a reverse association was found in higher social class families (for performance IQ, P value for interaction = 0.0013) among whom there was a wider range of MeHg exposure. Among 40 SNPs showing nominally significant main effects, MeHg interactions were detected for rs662 (paraoxonase 1) and rs1042838 (progesterone receptor) (P < 0.05) and for rs3811647 (transferrin) and rs2049046 (brain-derived neurotrophic factor) (P < 0.10).
CONCLUSIONS:
In this population with a low level of MeHg exposure, there were only equivocal associations between MeHg exposure and adverse neuropsychological outcomes. Heterogeneities in several relevant genes suggest possible genetic predisposition to MeHg neurotoxicity in a substantial proportion of the population. Future studies need to address this possibility.”