Final answer:
The device used to hold the extraoral film and intensifying screens in dental radiography is called a cassette. It ensures the film and screens are in close contact to amplify the signal and reduce exposure time, complemented by lead apron usage and shielding for radiation protection.
Step-by-step explanation:
The device used to hold the extraoral film and intensifying screens is termed a cassette. In dental radiography, this device ensures that the film remains flat and maintains close contact with the intensifying screens, which serves to amplify the signal and reduce the exposure time. The use of lead aprons and appropriate shielding is also important to limit the patient's exposure to radiation during the imaging process.