Tuesday, January 8, 2008

Where are all the autistic children of dentists?

photo credit-Conor Lawless
Creative Commons license

Once again, the purported link between mercury/thimerosal and autism is in the news. This months "Archives in General Psychiatry" contains an article which looks at the continuing increase in the reported prevalence of autism in California while the amount of mercury is declining, and there is also an accompanying commentary in the same issue.

This article and commentary were discussed by Kristina Chew. Mark Blaxill, a leading proponent of the "autism=mercury poisoning" line of thought, backpeddles somewhat without totally conceding that the theory is dead. Brett of 29 Marbles asks what it would take for either side to change their mind.

Although I ultimately look to science to inform my opinions on things such as causality, I am not above referring to common sense, which is not a bad place to start when considering what kind of studies should be done.

One of the things that has made me doubt the whole autism=mercury poisoning thing from the start are dentists, and the amalgams they place. Specifically, where are all the autistic kids who had dentists and dental assistants as parents? More specifically, where is the large group of autistics that are 35-55 years old that had dentists or dental assistants as parents?

Why do I choose that age range? For a couple of reasons. Since autism wasn't described until the 1940's or so, I wouldn't expect older autistics. Also, this period would correspond to a time when dental caries were rampant (pre-fluoridation of water), as well as a time when handling of mercury and amalgam in dental offices was very casual. Mercury and metal filings (silver and zinc) used to be hand measured into a device, which then shook them together (right at the chairside) until they became a soft "amalgam" which was then packed into the cavity in the tooth. The dentist is typically "right in your face" as (s)he packs the amalgam into the tooth.

While some people today still blame mercury fillings for the exceedingly small amount of mercury vapor that is released by chewing on amalgam fillings, no one disputes that the greatest period of exposure to mercury is when the amalgam is first being mixed together. Since the 1970's or so, dental amalgams have come in a pre-proportioned sealed container, which minimizes the amount of mercury in the air in a dental office. Also, the number of amalgams that are placed today, while still large, pales compared to the past. Fluoridation started in the U.S. in 1955, and by the 1960's started to catch on. This resulted in a lot less exposure to mercury per child.

But between the time that autism was first described and the decline in amalgam fillings being placed in children there should have been an epidemic of children identified with autism, which declined as fillings per child dropped off. There should have been an even bigger incidence in the children of dental workers (dentists and dental assistants) who were occupationally exposed on a large scale to mercury vapor.

Where are they?

There are no studies that have shown this, and I am not even aware of any anecdotes of this phenomenon happening.


Maddy said...

Oh dear, you mean we can't use dentists as a scapegoat? What a shame.

Chuck said...


A dentist put up the starting money for the local autism school to help his son and one of his assistances has a child on the spectrum.

Ange said...

There's a local dentist that has a teenage son on the spectrum. But my husband sells cell phones, and we have 2 on the spectrum. The guy down the road is a pilot. He has a son on the spectrum. The guy down the other road is a programmer. He has a son on the spectrum. The guy across the street from him is a landscaper....

Since both of my children had issues at birth, I have been told by someone that my fillings, flu shots (which I've never had), etc. that must've caused the mercury poisoning when I was pregnant.

Club 166 said...


I wondered how long it would take for someone to bring up someone they knew with a dental connection.

Out of the 161,000 dentists and over a million dental assistants in the US, there are bound to be 1000's of autistic offspring if they follow the general prevalence of 1:150.

What should have been happening is a much higher prevalence decades ago, when mercury exposure in the dental environment was much higher.

No one has shown that.


kristina said...

But don't we have to account for the sorts of persons who might choose a career in dentistry.....certain personalities/characters----

Marla said...

I really enjoyed reading this. You raise some very interesting areas of study. The comments are always good too. I like Kristina's comment.

Steve D said...

Hi Joe -
This is a great angle on the issue, one I certainly had never considered before.
The Blaxills of the world will never concede the issue, they'll just invent new variations of their theories. Anything to avoid cognitive dissonance, after all.


Chuck said...


Do you know of any studies of the physical or mental well being of those in the dental profession and their immediate offspring?

Maybe the dental community just doesn't like to get drilled!

Club 166 said...


The only associated diseases and states that tend to get studied in dentistry are suicide, depression, substance abuse, and "burnout".

Suicide may or may not be a bit higher than the general population rate, depending on the article you read. Substance abuse is probably the same as the general population (about 10 percent sometime over a lifetime), and depression is about the same as the general population (about 10 percent during any given year).

I have seen no studies that look at offspring of dentists.


The attributes that are typically ascribed to dentists are "perfectionists that become frustrated easily when things don't turn out perfectly, compulsively attentive to details, conscientious, and deferrers of gratification".

Not sure what all that adds up to.


Jen P said...

Is there a study somewhere about testing the metal levels in children's hair??? I was curious if this was hearsay or true because I've formed a hypothesis based on that study if it actually exists.

Daisy said...

The few dentists in my peer group (mainly high school and college classmates) were actually people who pursued an MD program and changed their mind on the way there. (For a variety of reasons, as far as I know.)

~Miss Nelson said...

I enjoy reading this. I would have never made the connection. I do know two dentists that have children with autism.

Anonymous said...

Finding Dentists with Autism Spectrum children is obviously going to happen, but now take into the fact that you are looking for Fetal poisoning. This now reduces to female Dentists and Female Dental Assistants children. From there you would have to start looking at the percentages.But the real question is why, now, when we have become more aware of certain chemicals and possible effects that they may have on the human mind and we reduce our exposures, are we seeing Autism Spectrum increases. Partially better Diagnoses, but that can't be all. Of course we shouldn't put poisons into our bodies, the results are always negative.The reality when something goes wrong especially with our children we want somebody or something to blame. But what if there is nobody to blame what if it is just genetic irregularities to chromazome 16 and that's all.


autismfamily said...

This is a great question. Back in the early 70s I went to the dentist for the first time due to a chipped tooth and found out I had 36 cavities. A dentist came to the school twice a year to check students and I never had any they said.

I spent 8th grade summer getting them all filled with gas. Anyway when I was pregnant with my almost 13 year old I went to the Dentist and the ex (who is schizophrenic) refused to allow me to sit in chair and get anything done and I had terrible teeth and issues.

Both my sons are on the spectrum, ages 11 and 12. I took the older son to the dentist a few months ago and he needs some fillings done and a root canal and an ortho consult for braces.

The younger one goes to childrens hospital where they have the papoose board and several people to assist in cleaning teeth and looking inside his mouth. We can only handle this every few years.

My sister was born with a brain tumor, my brother had spinal meningitis as a baby, my grandmother and her sister died of alzheimers and the ex is schizo.

Bad teeth do run in the family and thankfully I have dentures now and no more pain to endure.

Very interesting question and I strayed with my answer.

nyscof said...

Fluoride May Damage the Brain, New Report Says

New York – February 26, 2008 -- "It is not clear that the benefits of adding fluoride to drinking water outweigh risks of neurodevelopment or other effects such as dental fluorosis," according to an Institute for Children's Environmental Health report. (1)

Fluoride chemicals are added to 2/3 of U.S. public water supplies ostensibly to reduce tooth decay. Fluoride is found in dental products, supplements and virtually all foods and beverages (2).

"Excessive fluoride ingestion is known to lower thyroid hormone levels, which is particularly critical for women with subclinical hypothyroidism; decreased maternal thyroid levels adversely affect fetal neurodevelopment," reports a prestigious committee of scientists and health professionals in a “Scientific Consensus Statement on Environmental Agents Associated with Neurodevelopmental Disorders.”

Studies they reviewed and others link fluoride to brain abnormalities and/or IQ deficits. (3)

"The question is what level of exposure results in harmful effects to children. The primary concern is that multiple routes of exposure, from drinking water, food and dental care products, may result in a high enough cumulative exposure to fluoride to cause developmental effects," they write.

"Given the serious consequences of LDDs [learning and developmental disabilities], a precautionary approach is warranted to protect the most vulnerable of our society," the authors caution.

"It's time to stop water fluoridation," says lawyer Paul Beeber, President, New York State Coalition Opposed to Fluoridation. “With many neurological diseases, such as autism and ADD, afflicting too many American children, fluoride's dubious promises of less cavities no longer outweigh fluoride's serious health risks," says Beeber.

The National Research Council reviewed fluoride toxicology evidence and reported in March 2006 that studies linking fluoride to lowered IQ are plausible.(3a)

"The real dental dilemma facing American children today is their inability to get dental care," says Beeber. “Eighty-percent of dentists refuse Medicaid patients (4) and 108 million Americans don’t have dental insurance (5),” says Beeber.

Studies show that when fluoridation ends, cavities actually go down. (6)

Please sign the petition urging Congress to end fluoridation and hold hearings about why federal officials continue to promote water fluoridation in the face of growing scientific evidence of harm at http://www.FluorideAlert.org/Congress .

Dr. Phyllis Mullenix was the first U.S. scientist to find evidence that fluoride damages the brain. She published her study in a respected peer-reviewed scientific journal (7) and then was fired because she wouldn’t squelch it.(8)


1) Institute for Children's Environmental Health, “Scientific Consensus Statement on Environmental Agents

Associated with Neurodevelopmental Disorders,”

Developed by the Collaborative on Health and the Environment’s

Learning and Developmental Disabilities Initiative

November 7, 2007 released February 20, 2008


2) USDA National Fluoride Database of Selected
Beverages and Foods - 2004 http://www.nal.usda.gov/fnic/foodcomp/Data/Fluoride/Fluoride.html
3) http://www.fluoridealert.org/health/brain/index.html#human

3a) The National Academies of Science, Committee on Fluoride in
Drinking Water, National Research Council, "Fluoride in Drinking
Water: A Scientific Review of EPA's Standards," March 2006


4) Slate, “Hidden Rations Why poor kids can't find a dentist,” by Anne Alstott
May 29, 2007 http://www.slate.com/id/2167190/

5) American Dental Education Association/American Association for Dental Research Testimony presented by Dr. Nick Mosca

March 27, 2007 Before the House Energy and Commerce Committee


6) http://thyroid.about.com/cs/toxicchemicalsan/a/fluoridepr.htm

7) Mullenix P, et al. (1995). “Neurotoxicity of Sodium Fluoride in Rats,” Neurotoxicology and Teratology 17:169-177)

8) Dr. Phyllis Mullenix interview:


Videos: Part 1 http://www.youtube.com/watch?v=9daqPRUWpMc

Part 2 http://www.youtube.com/watch?v=A4QrTcyrrvw

Anonymous said...

We would only be talking about maternal exposure through the placenta and through the breast milk. There are far more male dentists than female so this would narrow your study group.

Also, I would think that dentists as well as dental hygenists would have better teeth than the population at large and would, therefore, have less mercury fillings. They would also be more likely to have white composites since they do work in the dental industry, whereas many of the general population go with mercury amalgams because they are typically the only ones covered by insurance. Having many amalgam fillings in your mouth 24/7 would be just as dangerous as the exposure of a dentist without amalgams - this may offset any differences.

I would be interested to see a study of only the women and children with autism. I know 5 women in the dental industry. 2 dental hygenists have children with disabilities, 1 hygenist has fibromyalgia (so did I before I got my amalgams out and did chelation), and 1 dentist has 2 girls and a boy (the boy is ADD - and of course boys are more susceptible to damage from mercury).

Sean said...

Autism is such a mysterious condition for me. I read that there are numerous factors that can increase the chance of having an autistic child to be born. But in my opinion, I don't consider autism as a sickness or a defection of a human being, but there are ways that we can avoid this and it will be fantastic if we'll learn how to. In the dental standpoint, there are a lot of dentist (Murrells Inlet, SC based clinics) that can provide excellent service to everyone. It also made me remember the first time that my autistic cousin went to the dental clinic. As I've seen in his eyes, he doesn't seem to get vexed by the procedure.

After the procedure, we went to the restaurant to congratulate him for a job well done, just to encourage him near our place at Murrells Inlet, SC. Dentists, with the test of time, had their skills evolved into fruition to serve the people.

sam said...

i just wanted to say how much i enjoy reading your blog. in a world full of spin, it's nice to get some fact-based analysis.
keep up the good work.

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Anonymous said...

I was a dental nurse and my son has autism.

If you doubt the danger of mercury, research Pink Disease. In the late 1930's in Australia infants were presenting with autism like symptoms. It was discovered that they were suffering mercury poisoning, which was an ingredient in teething powder. A sad story if you care to read into it further.

Unknown said...

I would think children of dentist and even dentist themselves are most likely not to, due to their profession, have dental fillings. I have traced 4 generations of the women in my family and can easily see how not only the quality of our teeth deteriorated, meaning more and more fillings, in each generation but so too has the mental and physical health issues. When I look at the long list of health challenges that are now being associated with mercury exposure... we all, having different health issues, cover about 75% of symptoms listed, Now we have a 5th generation female who is less than 2 years old, who of course will pay for the slowly damaged and dinged DNA and mitochondria that has been occurring in the last 100 years of our family tree. My, Autistic, daughter chose to breastfeed; I can only wonder what kind of microbial mess (good bacteria verses bad types) she is passing on to my granddaughter in what use to be the best option to feed a baby???