Playing Doctor: Evidence-Based Orthodontics
I was asked by the editors to address the limitations of evidence-based orthodontics (EBO). To me, the EBO movement is merely a sensible exhortation to use the best available data in the treatment of individual patients. Its ultimate limitation, therefore, is the soundness of the best available information. Beyond that, the trick is to figure out what that best treatment is. In my naïveté, I am surprised that this reasonable step is so controversial. Market pressures aside, I can see only two potential limitations to the EBO decision process: the specialty’s attitude toward evidence and the quality of the evidence itself. Unfortunately, the former tends to trump the latter.
Contemporary orthodontics is dominated by desultory conflict. Extraction versus expansion (with the correct bracket and archwire, of course) and one stage versus two are obvious examples. In a perfect world, one might expect the specialty to look to its researchers in both “town and gown” to generate evidence upon which decisions can be based. To a first approximation, our controversies, although clinically important, are relatively simple, and the questions they generate are obvious. Can expansion be an effective substitute for extraction? Is it stable? Does a first stage add value to a treatment? If it does, what is the value and under what circumstances does it accrue? In orthodontics, however, those who attempt to answer these questions and the methods they use often are seen as the problem rather than the solution. I will argue that this attitude of studied contempt and inattention is perhaps the real limitation. How can it have come to this?
Malocclusion isn’t a disease; treatment success and failure are ill-defined. Indeed, experience teaches that everything works well enough to support a practice. You use your methods, I’ll use mine. Because history reveals its alternatives neither to the individual patient nor to the clinician, the differences among treatments, no matter how great, are of little practical significance to the orderly flow of commerce. When everything works, science can be an unwelcome intrusion. Controversy is license. Good news for the orthodontist; bad news for the specialty.
Imagine, if you will, that a NASA tracking station has received a message from an infinitely advanced civilization saying that a robot is about to land at home base in Yankee Stadium (I have in mind something like Gort from The Day the Earth Stood Still). The purpose of this interstellar mission is to end sectarian violence and mistrust by telling us whether God exists, and, if so, which of our religions is the True Faith. Do you think the religious leaders of the World would rush to New York, beatific smiles on their faces, eager to join hands and learn the truth? Somehow I doubt it. I suspect that only a scattering of atheists and agnostics would welcome such an amazing revelation. For the rest, it would be a potentially catastrophic, soul-shattering event: at best, N − 1 religions would turn out to be “wrong” and thus in need of replacement by a foreign, perhaps even alien, belief system. Given that religions tend to feature ethical guidelines and precepts that support a “successful” life (however you may wish to define success), the impact of such a truth on our day-to-day lives would be beyond comprehension. In orthodontics, evidence is the intrusion that threatens the “philosophical” foundation of thousands of “successful” practices. Who or what is to blame? The schools, their researchers, and this “evidence-based treatment” nonsense!
Generating evidence in its various forms is a major part of a university’s mission. Nearly a century ago, when proprietary institutions fell into disrepute, orthodontics needed a respectable home. The universities seemed a perfect choice. Indeed, our founding fathers—folks like Kingsley, Angle, Farrar, Hellman, and Case—as well as the leaders who followed, took as an article of faith the proposition that orthodontics is a science. We belonged in academia. Unfortunately, our leaders occasionally championed, in the name of science, fanciful, idiosyncratic, largely unproved treatment “philosophies,” some aspects of which were so recondite that they could only be quoted verbatim. Angle’s definition of the “line of occlusion” (1907) is a telling example: “… The line with which in form and position according to type the teeth must be in harmony if in normal occlusion.” Unfortunately, many of these guiding principles were unrecognizable as science by the academic establishments in which we had sought refuge: facial growth is controlled by trophic substances oozing out of foramen rotundum; the upper molars cannot be moved distally; given the right force, tooth movement can grow bone; there exist reciprocal forces that will move canines but not molars; there exist reciprocal forces that will move molars but not canines; facial proportions do not change over time; if done properly, expansion is an effective substitute for extraction; airway expansion is the key to facial growth (rather than vice versa); proper facial development requires 32 teeth; in time, “growth” will ameliorate lower incisor crowding; malocclusion causes temporomandibular discrepancies (TMD); orthodontics can cure TMD, etc. Despite what “pointy-headed academics” might say, the various schools of thought feature—and always have featured—ideas and methods that can in fact support a successful practice. Isn’t this very success proof that contemporary practice is “evidence-based”? It is if survival is the only criterion. After all, history teaches that in orthodontics everything works well enough to pay the bills.
Clearly, there is a major philosophical problem with a nihilistic approach to treatment: if we were to clone a patient and have 100 orthodontists render treatment, there would be 100 treatment plans and 100 outcomes; however, only one would be best. Wouldn’t members of a learned specialty with medical/scientific aspirations want to know which of these treatments works best for a given patient? Apparently not, especially at a time when we can’t even agree on a definition of success beyond parallel roots and even marginal ridges. Given that nobody dies from anchorage loss, evidence is, for many, an unnecessary elaboration that serves only to impede the orderly flow of commerce. Expansion? Who knows? Perhaps it will work. After all, referring dentists don’t like extraction, and space closure is hard work. Perhaps a year of “functional” therapy will help. After all, what harm can it do? Besides, we can always pretend that second-phase brackets can grow bone and employ permanent retention until the patient moves or we retire. Aesthetics? People like “full” profiles; the teeth smooth out the wrinkles. The discussion usually ends with the calming folk wisdom that “there are many ways to skin a cat.” True; however, only one way is best. EBO is under attack because it threatens to reveal this best way and in so doing discredit many of the treatments that are the b/>