banned mercury amalgam dental fillings in 1997, after
determining that at least 250,000 Swedes have immune and other health disorders
directly related to the mercury in their teeth. Denmark ban amalgams
in 1999. In 1991, Germany's Health Ministry recommended to the German Dental
Association that no further amalgam fillings be placed in children, pregnant
women, or people with kidney disease, and in 1993 this was extended to include
all women of child-bearing age, pregnant or not.
By contrast, the American Dental Association (ADA) says replacing amalgam
fillings from non-allergic patients for the purpose of removing toxic substances
from the body is “improper and unethical.” The Canadian Dental Association (CDA)
insists that there is no scientific evidence linking medical illness symptoms to
mercury fillings, except relatively rare allergic sensitivity to mercury. (The
number of persons with a specific and detectable sensitivity to mercury may not
be so small. According to a Health Canada report, as many as 15 percent of
people with amalgam fillings show signs of sensitivity to mercury. Some American
researchers claim that at least 20 percent of people with amalgam fillings are
What gives? Are the Europeans and Scandinavians hysterical Cassandras, in a
sweat about nothing, or are the North American dental associations concerned
about things other than patient health? Are mercury amalgam tooth fillings
dangerous or not?
Amalgam tooth fillings are an alloy of 50 percent mercury, 35 percent silver,
13 percent tin, 2 percent copper, and a bit of zinc. Mercury toxicity was known
in the 19th century, but amalgam's cheapness, ease of placement, and durability
kept it popular. Dentists argue that mercury fillings last longer than resin
composites, and are more gentle to tooth pulp. Composites also require more
skill and time to place.
Unfortunately, mercury is a poison that penetrates all living cells of the
human body. It is more toxic than lead, cadmium and arsenic. The smallest amount
of mercury that won't damage human cells is unknown. Autopsy studies show a
correlation between the number of mercury fillings and mercury levels in the
brain and kidneys. Research also indicates that amalgams have an adverse effect
on the immune system's T-lymphocyte count.
is a poison that penetrates all living cells of the human body. It is more toxic
than lead, cadmium and arsenic. The smallest amount of mercury that won't damage
human cells is unknown.
Scrap dental amalgam is classified hazardous waste by the American
Environmental Protection Agency, and by law must be stored in unbreakable,
sealed containers, and handled without touching. Dr. Sandra Denton, M.D., who
specializes in treating chronic mercury toxicity, asks: “What is it about the
mouth that makes this same stuff non-toxic?” Referring to American Dental
Association (ADA) claims that amalgams have been proved safe in studies, Dr.
Denton challenges them to produce such studies. They have not. “On the other
hand,” says Denton, “research documenting mercury toxicity is voluminous.” She
has collected some 3,000 articles and several books on the topic.
A Danish study found that Multiple Sclerosis (MS) patients had eight times
higher levels of mercury in their cerebrospinal fluid than healthy controls. An
article in the Journal of Forensic Medicine & Pathology states: “Slow
retrograde seepage of mercury from root canal or Class V amalgam fillings...may
lead to multiple sclerosis in middle age.” Dr. Hal Huggins of Colorado Springs,
Colorado, a dentist who has MS himself, treats MS victims and people with other
chronic health problems by removing mercury amalgam fillings as well as with
detoxification and nutritional supplementation. He claims that 80 to 85 percent
of his patients improve significantly.
Despite Huggin's successes, the U.S. Multiple Sclerosis Society opposes
mercury amalgam removal, stating that they have found no scientific correlation
between amalgams and MS. Dr. Huggins counters that if his results are to be
written off as “anecdotal” or “placebo effect”, then he has the largest
collection of sustained recurring anecdotal placebo responses in the world.
Antibiotic resistant bacterial disease has become a significant and growing
public health problem over the past decade. Studies show that genes protecting
bacteria against mercury poisoning often bundle together with other genes that
give bacteria antibiotic resistant qualities. If amalgam fillings stimulate and
maintain populations of mercury-resistant bacteria, it's no major stretch to
suggest that they might also be an agent in developing antibiotic-resistant
bacteria. Research by Dr. Anne O. Summers, et al., at the University of Georgia
shows such a relationship in monkeys. Dr. Summers put mercury fillings into the
molars of monkeys. Within five weeks bacteria in the animals' intestines became
resistant not only to mercury, but also to common antibiotics like penicillin,
streptomycin, and tetracycline.
Another monkey study by Dr. Stuart B. Levy at Tufts University found that
before having mercury fillings, an average of one percent of the monkeys' oral,
and nine percent of their intestinal Enterobacteriacae were
antibiotic-resistant. After receiving mercury fillings, 13 percent of oral and
up to 70 percent of intestinal bugs became antibiotic resistant. The ADA
responds by reiterating its stand that mercury fillings are safe, and arguing
that animal studies “cannot be viewed as affecting humans.”
It is well-established that elemental mercury vapour emits from
amalgam tooth fillings during chewing, brushing, and eating hot and/or acidic
It is well-established that elemental mercury vapour emits from amalgam tooth
fillings during chewing, brushing, and eating hot and/or acidic foods. Most of
this vapour is inhaled. allowing efficient absorption across the alveolar
membrane in the lungs. Mercury easily crosses the blood/brain barrier – the
brain and nervous system's main natural defense against many toxic substances.
It can bind strongly to sulfur-containing proteins in nerve tissue (which may
explain the association with MS – a disease of the nerve sheaths), and deposits
in virtually all body tissues and organs. In experiments on mercury fillings in
sheep, Dr. Murray Vimy, a dentist at the University of Calgary, proved that
mercury migrates from the teeth into nearly all body tissues, especially the
brain, kidneys, and liver.
The average dentist handles two or three pounds of mercury annually.
According to Consumer Reports, up to 10 percent of dental offices have
mercury vapour levels exceeding 50 micrograms per cubic metre of air – the upper
limit considered safe for eight-hour workplace exposures. Dr. Sandra Denton
cites a study at the University of North Texas that found neuropsychological
dysfunction in 90 percent of dentists tested. Female dental personnel have a
higher spontaneous abortion rate, higher incidence of premature labour, and
elevated perinatal mortality, which has been substantiated by the EPA to be
characteristic of women chronically exposed to mercury vapour. Stillbirths are
significantly correlated with maternal blood mercury levels. Methyl mercury, the
organic form of mercury that forms after oral ingestion of mercury, is 100 times
more toxic than elemental mercury. Methyl mercury easily crosses the placental
barrier and builds up 30 percent higher red blood cell levels in the unborn
child than the mother.
The CDA counters that with billions of mercury amalgam fillings placed, there
is no apparent epidemic of ill health effects. However, others argue that so
many people have mercury fillings that no effective control group exists. Former
Health Canada biologist Mark Richardson, who researched the scientific
literature on mercury toxicity in preparing a risk assessment, notes that it is
people wanting to maintain the status quo who conclude that there is no evidence
that mercury toxicity is a health problem. He refers to the tobacco industry's
stalwart insistence that studies linking smoking to lung cancer are
unscientific. Richardson's report, under consideration by Health Canada,
recommends limiting the number of mercury fillings per person.
Stubborn reluctance of dental associations to acknowledge the health risk of
mercury toxicity from amalgam fillings may indeed have much in common with
tobacco company tactics. If diseases like Multiple Sclerosis, Chronic Fatigue
Syndrome, and Multiple Chemical Sensitivity are linked to mercury exposure from
tooth fillings, significant potential exists for individual or class action
lawsuits against dentists. Indeed, the German Dental Association has stated that
if the government recommends further limitations on amalgam use, it will advise
its members to stop using amalgams completely due to increasing risk of legal
liability. The truth will eventually out, and if mercury fillings are indeed
eventually proved harmful, a history of foot-dragging will not bolster the
dental community's case in court.
Dr. Murray Vimy is certain that every time you chew, brush, or grind your
teeth you absorb mercury. However, he councils against panic and suggests that
mercury fillings be replaced with non-mercury materials like resin composites,
porcelain, or gold, as needed. There is some risk that mass replacements could
expose the patient to more mercury than if old fillings were left alone.
Charles Moore is a freelance writer
living in rural Nova Scotia who specializes in health issues.