Final answer:
Temporary acrylic crowns appear radiopaque on radiographs because they are dense enough to block X-rays, showing up as lighter areas on the image.
Step-by-step explanation:
Temporary acrylic crowns appear radiopaque on radiographs. When an X-ray beam is passed through the mouth, the acrylic material is dense enough to block some of the X-rays, resulting in it appearing lighter or “whiter” on the radiograph.
This is typical for restorative materials, such as metal amalgams and certain composite and ceramic materials, which all tend to appear radiopaque due to their density relative to the surrounding biological tissues.