Just when I think I’m out…they pull me back in. Last week I wrote a blog post warning readers to be aware of chauffeur knowledge. Of course I am always on the lookout for potential chauffeurs, so when it came to my attention that TV doctor, Mehmet Oz did a series of shows called Toxic Teeth: Are Amalgam Fillings Safe? my chauffeur radar sounded an alarm.
Just the act of Googling Dr. Oz will show you that he has an opinion on just about everything known to man, and with a surgeon’s credentials and the backing of the media…you always have to wonder about his purpose. Not that I am the suspicious type, but when he treads on my industry…I prefer the truth…if there is a truth.
I don’t want to get into the so called facts about amalgam. The Internet is filled with conflicting information (of course if you have a dog in the fight you won’t think the info conflicts). That’s why we may never know the truth about many things. Yet we all have to make decisions…everyday. Amalgam? Composite resin? Gold (there’s one Dr. Oz never mentioned)? X-rays? Centric relation occlusion? Neuromuscular occlusion?
Did you ever notice how all the chauffeurs start off by saying, “The Truth About…”
That’s what Dr. Oz did—he used words like poison, firestorm, potential toxicity, all the while an ominous soundtrack played like the one you hear when a political candidate has an ad about his opponent. Well done production…but it doesn’t get us any closer to the truth.
I know the truth.
Well it’s my truth anyway. Another word for my truth is opinion...I formed it by observing the field for over forty years and working in the profession…I’m not the chauffeur. At the end of this post I will give you my truth.
Rolf Dobelli, in his fascinating book, The Art of Thinking Clearly, writes about two ideas that may come into play when making choices like the ones above: Neglect of Probability and Zero-Risk Bias.
The first one, Neglect of Probability is our tendency to make decisions based on magnitude rather than true probabilities. For example many people invest money in start-ups because of the high potential of profits to be made, and ignore the poor odds of a business actually making it.
Another example is the way many more people play the Mega- Jackpot lotteries even though the odds of winning are so much smaller compared to the normal lotteries. Magnitude over probability…got it? Good.
Now let’s talk about Zero-Risk Bias…this is a bit more complicated.
The example Dobelli gives is to examine two methods of treating drinking water. A river gets its water from two equally large tributaries. One is treated with method A and the other with method B. Method A reduces the risk of dying from contamination from 5 to 2 percent. Method B reduces the risk of dying from 1 to 0 percent.
So which would you pick?
Most people choose Method B because the threat of dying is reduced to 0. But with method A 3 percent fewer people die and only 1 percent for method B. Most people opt for zero risk…that’s the bias, but it’s a fallacy.
For a better understanding Dobelli uses the example of the U.S. Food Act of 1958, which prohibits food that contains cancer causing substances. The purpose of this ban was to get to zero risk of cancer. But it ended up leading to the use of more dangerous (but noncarcinogenic) food additives. It soon became impossible, economically to remove every banned substance. The only time zero risk makes sense is when the threat is so great that it would be catastrophic, such as an ebola virus outbreak.
The 16th century scientist Paracelsus told us that poisoning is always a question of dosage. Amalgam has been used as an effective restorative material for over 150 years. There is no dosage issue. Yet Oz tried to show the TV audience that there was a dosage issue.
He was called out on this by Steven Salzberg, a contributor to Forbes magazine.
It is worth reading the article because he identifies David Wentz as someone who is qualified to run a shoddy experiment. Wentz owns a nutritional supplement company. It’s funny how Oz tells the viewing audience how to reduce the amount of mercury vapor in their mouths…with supplements.
It’s also funny that the segment that showed the experiment has been taken down from the Oz website.
So by magnifying the effect of the mercury in amalgam he is calling for people to apply the fallacy of the zero risk bias. Dobelli points out that two researchers from the University of Chicago have shown that people are equally afraid of a 99% as they are of a 1% chance of contamination by toxic chemicals.
Irrational, but common. That’s why I call Mehmet Oz a purveyor of chauffeur knowledge.
Dentists are mixed on this issue, with 47% of dentists not placing amalgam fillings. I am one of them.
But not for Dr. Oz’s reasons. My truth or opinion came to me over time.
I have been around since the beginning of the advent of composite resin. The first and second generation of composites were inferior to those we have today. They were and still are technique sensitive. Amalgams are cheaper and easier to place—and last longer. As the materials improved and my technique improved and the patients demanded more esthetic dentistry…I went exclusively to composite resin.
But…let’s go back to zero risk bias. Are there no risks with composite resins? Are those risks less serious than mercury poisoning? Of course there is an answer…gold. But even Dr. Oz admits the problem could be an economic one.
So you see why finding the truth is difficult. Each dentist must find his or her own truth.
In the case of occlusal philosophies, we don’t have to worry…the risks aren’t high enough for Dr. Oz to give his opinion. Hopefully he stays away from the x-ray issue.
I would challenge the chauffeur on the amalgam issue but I would probably lose — there is also a handsome bias in this country.