I read the recent article by Hans, Palomo, and Valiathan with great interest. Their history of imaging in orthodontics was presented admirably, as would be expected of authors so very knowledgeable in this field.
I have 2 observations to make. The first is that Broadbent was not the only inventor of the cephalostat; Herbert Hofrath, in a paper also published in 1931, described a “teleroentgenogram” machine with a head holder for taking “roentgenograms in ‘orthoprojection.’” The paper appeared in a German journal and is not as well known as the Broadbent paper, but credit should be given.
The second point is much more important and pertains to the concluding statement that “there are potentially 1.2 million subjects for orthodontic research” (in the United States), followed by the exhortation to use cone-beam computed tomography (CBCT) as “the image record of choice and take images before and after treatment” to “have a sample large enough to answer even the most challenging questions facing our specialty. The choice is ours.” I find these statements very disconcerting because there is a high potential for them to be misconstrued.
The 1.2 million patients are not research subjects; they are people who come to our offices to be treated, not to participate in a research project. If we decide (our choice) to carry out such grand-scale research, then we should obviously follow the 2 basic requirements of medical research: obtain informed consent (the patient’s choice) and get approval from an ethics advisory board (or institutional review board).
Informed consent requires that the patient understands the benefits and potential harms of the research. The authors propose taking 2 CBCT images, 1 before and 1 after treatment. Whereas a cephalometric/panoramic combination before treatment is accepted as a routine procedure for most orthodontic patients, a CBCT image is not. The authors suggested that the latest machines have a very low dose, and a CBCT image would therefore be advantageous, but there are currently 2 problems: (1) how many such machines are now in operation and how many of the 1.2 million patients would still be imaged by the older machines? and (2) with a lower dose comes lower image quality; the diagnostic efficacy of the low-dose images has not yet been evaluated.
In any case, accepting that the “before” image is beneficial to the patient and required for treatment, what about the “after” CBCT image? What is the specific benefit to the patient (every patient: 1.2 million in the United States alone) of a CBCT image after treatment? The informed consent document should explain that this image is taken mostly, if not solely, for research purposes. It would be interesting to see the public’s response to such a nationwide research initiative, presumably led by the American Association of Orthodontists.
Assuming that the above concerns are addressed and assuming that the patients give us consent to use them as research subjects, which are the “most challenging questions facing our specialty”? Have we formulated specific questions and a specific research plan? Do these challenging questions really need CBCT images to be answered? What is the evidence for which a sample size of 1.2 million is required? How many of the 1.2 million images per year will go unused and the radiation dose will have been in vain?
I understand that it is not easy to restrain the enthusiasm for new technology or to resist the temptation of using the marketing force of a CBCT machine in one’s private office. It is for this reason that the authors, who function in the academic environment and show exemplary scientific conduct, should be clear in their position. I hope I have demonstrated that their intent could be misunderstood and that they will take this opportunity to clarify it.