Cone Beam CT: Dental Association Panel Calls for Caution

Laird Harrison

August 09, 2012

August 9, 2012 — New guidelines on cone beam computed tomography (CT) scanning by the Scientific Affairs Council of the American Dental Association (ADA) imply that dentists could be responsible for analyzing the complete image from their scan, not just reviewing the maxillofacial area.

The guidelines, published in the August issue of the Journal of the American Dental Association, urge dental professionals to use the new technology only when necessary, and only if properly trained to interpret the findings.

Cone beam CT has been growing in popularity among dentists who like the 3-dimensional images it produces. However, the scanners subject patients to much higher doses of radiation than 2-dimensional radiology, making them somewhat controversial.

The ADA guidelines hold the person interpreting the image responsible for all the information it contains. "Regardless of the primary purpose for the selection of [cone beam CT], the complete image data set must be interpreted by an appropriately qualified health care provider (such as a dentist or a physician)," they write.

That surprised Donald Tyndall, DDS, PhD, a professor of diagnostic sciences at the University of North Carolina, Chapel Hill, because it implies a new level of responsibility for general dentists.

"One thing that is a surprise is that the ADA did recommend that every cone beam CT be accompanied by a report of all the imaging data, and not just the area of interest," Dr. Tyndall told Medscape Medical News.

"Some of the cone beams do almost the entire skull, and most dentists are not trained outside the maxillofacial area," said Dr. Tyndall.

Legal Implications

The recommendation could have legal implications because attorneys sometimes cite the guidelines of professional groups in malpractice lawsuits. Potentially, dentists who miss an important abnormality in the brain or throat revealed by scan — even one that was only intended to scrutinize the teeth — could be liable.

The ADA recommendations are only the most recent in a series of guidelines various organizations have issued to help dental professionals make the best use of the relatively new technology.

In addition, the American Academy of Oral and Maxillofacial Radiologists (AAOMR) has issued a series of position papers on cone beam CT in general, on cone beam CT for endodontics, and in June, led by Dr. Tyndall, for cone beam CT for implants.

In agreement with the new ADA guidelines, the AAOMR's 2008 general statement specifically states that it would be "erroneous" for a practitioner to assume no responsibility for findings beyond those needed for a specific task.

The new ADA guidelines also touch on the controversial question of training. They urge practitioners to get appropriate training and suggest that the Commission on Dental Accreditation and similar educational organizations formulate requirements for practitioners.

"It's the feeling of many oral radiologists that dentists should at least have 2 days of training on cone beam CT, but a lot of states don't require anything," said Dr. Tyndall. "There are very few [cone bream scanner] companies that offer a full 2 days."

Yet dentists cannot rely on maxillofacial radiologists to interpret all the cone beam scans they do, because there are not enough maxillofacial radiologists, said Dr. Tyndall.

The guidelines stop short of recommending cone beam for specific tasks, saying only that "Dental practitioners should prescribe [cone beam CT] imaging only when they expect that the diagnostic yield will benefit patient care, enhance patient safety or improve clinical outcomes significantly."

That guidance is not particularly surprising, but it is important. "It's relatively obvious," acknowledged John Timothy Wright, DDS, a professor of pediatric dentistry at the University of North Carolina, Chapel Hill, who chaired the ADA committee making the recommendations. "It will at least remind dentists to use all due diligence," he told Medscape Medical News.

The AAOMR implant guidelines on implants get much more specific: they advise anyone placing a dental implant to use cone beam imaging, even single implants in relatively straightforward situations.

"As it currently exists, the literature shows that it's a benefit," Dr. Tyndall said. "It's a wonderful technology."

He acknowledged that some practitioners would not agree. "It's like air conditioning," he said. "If you have never had it, you don't know what you're missing."

The guidelines authors and Dr. Wright have disclosed no relevant financial relationships. Dr. Tyndall has received honoraria from imaging equipment manufacturers Sirona, Patterson Dental, Henry Schein, Benco Dental, and Carestream Dental.

J Am Dent Assoc. 2012;143:899-902. Full text


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