Telling a radiographic artifact from real pathology is a reading skill, and it is less settled than the tests for it suggest. Some of the radiolucencies you will be asked to call are not lesions at all — they are the beam, the geometry of the tooth, or your own visual system.
Learning to read dental radiographs means building two things that can be measured separately: where your eyes go, and what you make of what they land on.
You'll be told to read every radiograph the same way, in a set order. That advice isn't wrong, but the order your eyes travel is not what separates a strong reader from a struggling one. Two habits carry most of the load, and neither depends on which route you pick.
Interproximal caries hides under the contact point and looks smaller on a bitewing than it really is. Here's how to read the dark triangle and when to treat.