What is the center of rotation in panoramic imaging?

• A. A fixed point that does not change during exposure.
• B. A continuously moving point that adapts to jaw shape but not image distortions.
• C. A point that moves randomly during the sequence.
• D. A continuously moving point that adapts to the shape of the jaws, reducing distortion and optimizing image quality.

Answer: (D)

In panoramic imaging, the center of rotation is dynamic rather than fixed. It moves in a controlled way to follow the shape of the patient’s jaws, so the X‑ray beam and detector stay aligned with the dental arches throughout the rotation. This alignment helps keep structures at a consistent magnification and position as they sweep through the focal trough, which minimizes distortions and improves overall image quality.

A fixed center would place different parts of the jaw at varying distances from the beam during rotation, leading to uneven magnification and blurred or distorted areas. A moving center that adapts to jaw shape ensures the structures stay within the optimal imaging path, reducing distortion. That’s why the best description is a continuously moving center that adapts to the shape of the jaws, reducing distortion and optimizing image quality.