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Post Hoc, Ergo Propter Hoc

Post Hoc, Ergo Propter Hoc

My father had only one peculiar habit that I can remember. On the bottom shelf of our medicine cabinet was a pile of razor blades that he would use in order, taking one from the top, using it for a few days and then placing it on the bottom of the pile. He said that resting his razor blades made them sharp again and that they lasted for a long time. Most people achieved only small triumphs over the Depression of the '30s, and this was one of those.

Some time later, a Czechoslovakian engineer did the same thing, except that he placed his razor blades under a pyramid. He patented the idea and cardboard pyramids became the rage in his country and abroad--including the United States. Pyramidology became a cult science. What pyramids could do for razor blades, they could do for your body, my body, any body.

I suppose if my father had been a promoter instead of a schoolteacher, he would have marketed the Remarkable Razor Blade Rejuvenator, and gone on to produce larger versions for people to sit inside to cure their ills. At any rate, he didn't think he owned a magic medicine cabinet. He assumed it was something about the razor blades themselves and, with no knowledge of metallurgy, he believed that somehow resting the metal restored its sharpness.

If people were to feel better after sitting under a pyramid and if they were to believe it was due to the pyramid and I were to believe it was a placebo effect, there would be no harm done, unless someone were to try to cure a major disease or disorder that way. I would be surprised if pyramid therapy had not been used with some success for TMJ pain.

In much of what we do in the health-care professions, we cannot separate curative effects from placebo effects or from healing. It has been said that in medicine 10 percent of the people get better because of what the doctor does, 80 percent get better regardless of what the doctor does, and 10 percent will not get better in spite of what the doctor does. We have all had the experience of enduring a cold for three weeks and finally going to the doctor. In another week, the cold is gone. Was it the prescription that effected the cure, or was the time up for that cold?

In the case of the treatment of TMJ pain, almost every conceivable "cure" works on someone, at least for some time. When it does, the doctor is likely to think that what he or she did effected the cure. But was it the treatment? Or was it a placebo effect? Or was it a natural healing process?

Even in aspects of orthodontic treatment that seem more straightforward, there are threads of the same dilemma. We may give a patient a headgear to move upper molars distally. After a period of time, a cephalometric x-ray shows distal movement. Afterward, we find out that the patient did not wear the headgear. Certainly neither a placebo effect nor healing. Perhaps it was growth or mandibular repositioning.

Just as we may not be able to take the credit for effects outside our control, we also ought not necessarily accept the blame when those effects are undesirable. A patient who had orthodontic treatment, but also had a third molar removed, had the mouth open for prolonged periodontal treatment, yawned hugely, slept on his or her fist, was struck in the jaw by someone else's fist--who had a traumatic event that in time is likely to be overcome by healing--that person can sue his or her orthodontist on the basis that TMJ pain followed orthodontic treatment.

Orthodontists can be called to account--indeed, hold themselves accountable--for irregularities that occur post-treatment, even though it is well known that there are two kinds of post-treatment irregularity: relapse and physiologic change that can be seen in people who never had orthodontic treatment.

Similarly, although it is rare for a tooth to become nonvital following orthodontic treatment, it is far more likely to have been caused by a forgotten blow than by the orthodontic treatment. Other examples of so-called iatrogenic damage are at least a shared responsibility, including decalcification and periodontal breakdown. This does not absolve orthodontists from exercising good judgment and high standards of care, but it puts post-treatment events into perspective.

It cannot be assumed that if something happens--good or bad--following something that we did, it was necessarily because of what we did. It is highly advisable to have a thorough informed-consent form and to check off the points as they are discussed in the consultation, or have the patient check them off. It can be a reminder if an unwanted event occurs later.


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