Final answer:
German physicist Wilhelm Röntgen was the first to take a dental radiograph on a live patient, and he later suffered from cancer believed to be related to his experiments.
Step-by-step explanation:
The dental pioneer who was the first to take a dental radiograph on a live patient and later had his arm amputated due to cancer from experimenting on himself was German physicist Wilhelm Röntgen. While experimenting with electrical currents, he discovered a form of electromagnetic radiation, which would later be known as the X-ray. Röntgen's groundbreaking work began with a radiograph of his wife's hand and earned him the first Nobel Prize for Physics in 1901.