What is a common reason for crowns to be missing on a dental radiograph?

A common reason for crowns to be missing on a dental radiograph is excessive vertical angulation. When the x-ray beam is angled too steeply in a vertical direction, it can result in a projection that does not capture the entirety of the tooth above the gum line, including crowns. This is because the area being imaged may fall outside the field of view of the radiograph, leading to the crowns being missed entirely or appearing foreshortened.

In contrast, factors such as insufficient exposure time can lead to underexposed films, but typically, this would not specifically cause crowns to be missing; rather, it may result in darker images with less detail. Incorrect film development can lead to problems with image quality, but again, this does not specifically correlate with missing crowns. Patient anxiety during exposure may cause movement, which can lead to blurred images, but it does not typically result in missing crowns unless the patient moves at the precise moment of exposure that would affect the captured area.