Title: 
Side-effects: mercury contribution to body burden 
from dental amalgam.

Author: Reinhardt JW
Address : 
Department of Operative Dentistry, University of Iowa College of
Dentistry, Iowa City 52242.
Source : Adv Dent Res, 1992 Sep, 6:, 110-3

Abstract :

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.

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Title
Chronic encephalopathies induced by mercury or lead: aspects of
underlying cellular and molecular mechanisms.
Author : Rönnbäck L; Hansson E
Address : Department of Neurology, University of Göteborg, Sweden.
Source : Br J Ind Med, 1992 Apr, 49:4, 233-40

Abstract :
Long term exposure to low doses of mercury or lead can induce
neurasthenic symptoms with slight cognitive deficits, lability,
fatigue, decreased stress tolerance, and decreased simultaneous
capacity. After exposure to higher concentrations permanent
neuropsychological deficits can be seen. The present paper gives a new
idea of possible molecular mechanisms underlying the symptoms.
Impairments of astrocyte function are probably important, especially
due to their capacity to regulate the ionic and amino acid
concentration in the extracellular micromilieu, brain energy
metabolism, and cell volume. Recent results have shown that these
functions are under monoaminergic control. Aspects of therapy are
outlined.

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Title : Epidemiology, etiology, and prevention of multiple sclerosis.
Hypothesis and fact.
Author : Ingalls TH
Source : Am J Forensic Med Pathol, 1983 Mar, 4:1, 55-61

Abstract :
Slow, retrograde seepage of ionic mercury from root canal or Class V
amalgam fillings inserted many years previously, recurrent caries and
corrosion around filling edges, and the oxidizing effect of the
purulent response may lead to multiple sclerosis in middle age.
Epidemiologic studies of MS consistently reveal more neurological
disease in the north, inferentially because there may be less caries
and therefore fewer fillings done in the south. Clinical and
epidemiologic data also suggest that a second heavy metal, lead, may
operate almost interchangeably with mercury. Possibly, cases of
unilateral MS derive from mercury-amalgam fillings in ipsolateral
teeth, whereas the generalized disease may result from ingestion or
inhalation of volatile mercury or exhaust fumes of lead additives to
gasoline. The forensic and preventive-medical challenge is to identify,
monitor, and resolve questions of hidden heavy metal hazards in a high
technology society, especially those of lead and mercury. Further
clinical-epidemiologic and basic science studies of heavy metal assays
in whole blood, CNS tissues, packed cells, and serum are warranted.
Prevention awaits further testing of the hypothesis and experience with
substitute filling materials.