In paralleling technique, the central ray is oriented how relative to the tooth & receptor?

• A. Perpendicular to the Receptor Only
• B. Parallel to the Tooth and Receptor
• C. Perpendicular to the Tooth and Receptor
• D. Parallel to Both Tooth and Receptor

Answer: (C)

In paralleling technique, the goal is to produce a distortion-free image by keeping the receptor parallel to the tooth’s long axis and directing the beam straight through. To achieve this true projection, the central ray must strike both the tooth and the receptor at a right angle. So it is oriented perpendicular to both. This alignment prevents elongation or foreshortening and maintains accurate size and shape in the image. If the beam isn’t perpendicular—tilted toward or away from the tooth—the image would be distorted; if it were parallel to either the tooth or the receptor, distortion would also occur.