A new technology sweeping through dentistry -- especially orthodontics -- is called cone-beam CT scanning. It creates gorgeous 3-D images of the teeth and facial bones, but at a price of potentially high doses of X-rays, that carry a low risk (but still a risk) of cancer.

The risk accumulates with the more X-ray exposure there is, and sometimes dentists can run a child through the cone-beam CT scanner four times in the course of fitting braces.