Authors’ response

Writing a summary article on the history of craniofacial imaging (Hans MG, Palomo JM, Valiathan M. History of imaging in orthodontics from Broadbent to cone-beam computed tomography. Am J Orthod Dentofacial Orthop 2015;148:914-21) is similar to writing about the greatest quarterbacks in American football. Everyone has an opinion. In Cleveland, we would choose Otto Graham, whereas Denver would likely vote for John Elway. I am sure that every region in the United States would enter that debate from a different perspective!

Dr Halazonetis questioned our decision to not include the publication of Hofrath from Germany (also published in 1931 but months after B. H. Broadbent’s paper). Our decision was based on the following observations. First, Broadbent documented the ability of his cephalometer to acquire both lateral and frontal cephalograms, and established and explained the significance of the central ray coinciding with the line joining the “tops of the two ear supports.” In addition, his paper illustrated the use of “internal and external craniometrics points” to complete superimpositions and laid the foundation for our understanding of craniofacial growth and dental development in the different planes of space. The immediate impact of Broadbent’s work was felt across the country, as Alan Brodie, William Downs, and Cecil Steiner all used his technique as the basis for their publications. Finally, the long shadow cast by B. H. Broadbent remains intact through the Bolton-Brush Growth Study Center and the American Association of Orthodontists Foundation Legacy Collection. Although any serious student of the history of cephalometrics would certainly be aware of the pioneering work of Dr Hofrath in Europe, for the above-stated reasons we did not include his publication in our article.

In addition to explaining our reasons for focusing the early years of cephalometrics on Broadbent, we also appreciate the opportunity to clarify our position on the use of radiographic records for research, which both Drs Halazonetis and Spassov questioned. We do not support the use of ionizing radiation solely for orthodontic research on human subjects. Although the advancement of our understanding of facial growth and development in the past was facilitated by longitudinal studies such as the Bolton-Brush, considering what is now known about the potential deleterious effects of ionizing radiation on children and teens, such studies would not be approved by most if not all institutional review boards of major universities. And, although practitioners in private practices might undertake such a longitudinal study by substituting cone-beam computed tomography (CBCT) for cephalograms, it is highly unlikely. Therefore, the question about the use of CBCT for research boils down to this: “What radiographic images should be taken before and after orthodontic treatment?” We are in no way suggesting that any radiographic images should be taken for research purposes. So, we are really only talking about existing images. If the images exist, then they could be used to answer questions posed by the specialty. Of course, both pretreatment and posttreatment records would be the most useful for research purposes. Taking radiographs, whether panoramic and cephalometric radiographs or CBCT, before treatment would in most parts of the United States be considered the “standard of care.” Taking radiographs during treatment or at the conclusion of treatment probably varies quite a bit across our country. In our opinion, this decision is up to the practitioner. Taking radiographs after treatment allows the practitioner to identify potential areas of concern that have occurred during the orthodontic treatment. A partial list of these concerns might include apical root resorption, root dehiscence and fenestration, and the developmental stage of unerupted teeth. Practitioners interested in having this information to share with their patients need to take radiographs after treatment. The newest CBCT scanners offer low-dose modes, which allow the taking of a 3-dimensional image with less radiation exposure to the patient than panoramic and cephalometric radiographs and provide equivalent or better resolution and a lot more information. Based on our experience looking at several low-dose 3-dimensional images, there is nothing that we can learn from panoramic and cephalometric radiographs that we cannot learn from a low-dose image. It gives us more information with less radiation.

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Apr 4, 2017 | Posted by in Orthodontics | Comments Off on Authors’ response

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