Using 3D X-rays for orthodontic kids may up radiation risk

Researchers have indicated that some orthodontists may be exposing young patients to unnecessary radiation when they order 3D X-ray imaging for simple orthodontic cases before considering traditional 2D imaging.
 
A very small number of orthodontists utilise the 3D imaging on a routine basis when developing a treatment plan, and this raises concerns of unnecessary radiation exposure.

In contrast, the evidence summarised in Dr Sunil Kapila, lead author of the paper and chair of the Department of Orthodontics and Pediatric Dentistry at the University of Michigan School of Dentistry paper suggests that 2D imaging would suffice in most routine orthodontic cases. One of the tradeoffs for the superb 3D images is higher radiation exposure, Kapila said.

The amount of radiation produced by 3D computed tomography (CBCT) imaging varies substantially depending on the machine used and the field of view exposed, and some clinicians may not realise how much higher that radiation is compared to conventional radiographs.

One CBCT image can emit 87 to 200 microsieverts or more compared to 4 to 40 microsieverts for an entire series of 2D X-rays required for orthodontic diagnosis, Kapila said. Considering that the average US population is exposed to approximately 8 microsieverts of background radiation a day, 200 microsieverts equates to about 25 days worth of cosmic and terrestrial radiation.

"Keeping in mind that the radiation received has cumulative effects, adding unnecessary radiation exposure to the patient may result in a higher biological risks, particularly in the more susceptible young children. This is why selecting the patients that would benefit the most from this additional exposure needs to be done on a case-by-case basis," said Dr Erika Benavides, clinical assistant professor in U-M's Department of Periodontics and Oral Medicine.

The paper has been published in the journal of Dentomaxillofacial Radiology.