In recent years, the British Orthodontic Society has challenged the routine use of radiographs in orthodontics with publication of the third edition of its guidelines for clinical radiography. You might remember my editorial describing this change and how that common-sense approach appealed to me. This issue is important to the practice of orthodontics because we routinely treat children, but it is also being scrutinized in medicine. Conditions that once required laparoscopy for diagnosis can now be diagnosed on the screen. The best part was that radiographs were considered “noninvasive” and were both fast and painless. No wonder they have had such a significant effect on the practice of medicine. But research is continually being published that makes us wonder whether we have been carried away by our enthusiasm. Every day, more than 19,500 computed tomography (CT) scans are performed in the United States, subjecting each patient to the equivalent of 30 to 442 chest radiographs. Whether these scans will lead to better outcomes is yet to be determined.
European interests in this topic are represented by the SEDENTEXCT project (2008-2011) of the European Atomic Energy Community. It is an ambitious collaborative proposal that aims to acquire much key information necessary for sound, scientifically based clinical use of cone-beam CT (CBCT). This new organization is currently establishing provisional guidelines specifically for CBCT in dentistry. These guidelines include the following applications in orthodontics: determining tooth position and localization, resorption related to impacted teeth, and bone dimensions for mini-implant placement; assessing airways; and investigating orthodontic-associated paresthesia. Regarding root resorption with maxillary impacted canines, the provisional guidelines offer this advice:
For the localized assessment of an impacted tooth (including consideration of resorption of an adjacent tooth) where the current imaging method of choice is conventional dental radiography, CBCT may be used when the information cannot be obtained adequately by lower dose conventional (traditional) radiography.
As this project continues to compile evidence based on published literature, it is focused primarily on enhancing the safety and efficacy of CBCT.
With this rising interest abroad and related constituent resolutions introduced and acted upon by the 2010 House of Delegates, representatives of the American Association of Orthodontists and the American Association of Maxillofacial Radiology (AAOMR) are working on a joint position paper on the appropriate selection of diagnostic images for orthodontic treatment. AAOMR President, Dr Allan Farman of the University of Louisville, appointed Dr Mansur Ahmad to lead the initiative. He is an associate professor in the Division of Oral Medicine and Diagnosis at the School of Dentistry of the University of Minnesota. “The primary goal of this position paper is to develop guidelines for clinicians to decide which imaging technique will be most helpful in specific orthodontic conditions,” said Dr Ahmad. “The orthodontic specialty is currently using a variety of imaging technologies, ranging from cephalometric radiographs to CBCT.” A set of detailed guidelines will make it easier for the clinician to choose the best imaging technology for each situation. The paper will focus on all imaging, including 3-dimensional and conventional imaging: cephalometric, panoramic, and intraoral radiographs. “Our hope is that the position paper will help the orthodontic specialty to use radiographic equipment as effectively and efficiently as possible,” said Dr Ahmad. “I feel that our joint effort is a landmark in advancing the field of dentistry.” Since 2008 when the new British guidelines were published, the literature on CBCT has expanded greatly. “Realistically,” added Dr Ahmad, “some opinion will come from the experience of the authors in this area, which means that our paper will be and should be updated as the scientific knowledge base improves.”
As the effort to provide appropriate guidelines for CBCT imaging continues internationally, preliminary reviews show that the current literature does not yet support the universal use of this technology in all patients. With this in mind and until the guidelines are completed, orthodontists should use CBCT cautiously and always ask themselves whether the clinical question can be answered by conventional radiography. Radiographs should be taken only when justified clinically.