Panoramic Radiograph (OPG)
Definition
A wide-field tomographic image of the entire dentition and jaws on one film or sensor. Useful for overview but subject to magnification variation and distortion that limits precision comparison.
- Full name
- Orthopantomogram
- Coverage
- Entire dentition and jaws, one image
- Limitation
- Magnification variation and distortion
- Best use
- Overview, not precision comparison
Common questions
Why is an OPG less suited to point-by-point antemortem/postmortem dental comparison than periapical films?+
Its rotational tomographic technique introduces variable magnification across different regions of the arch, so two OPGs of the same person taken on different machines can show subtly different tooth proportions, which complicates overlay-style comparisons that assume consistent scale.
What does an OPG still contribute even with these limitations?+
It gives a reliable overview of restorations, missing teeth, root morphology, and pathology across the whole mouth in one exposure, which is often enough to narrow or exclude a match before finer imaging is pursued.
Related terms
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- Cone Beam CT (CBCT)
- A three-dimensional imaging modality producing volumetric data of the jaws at lower dose than medical CT. Allows multiplanar reconstruction and surface rendering...
- Digital Superimposition
- Computer-assisted alignment of two radiographic images to assess feature correspondence. Software adjusts size, rotation, and contrast to optimise overlay, and highlights matching...
- Frontal Sinus Comparison
- Identification method using the unique outline shape of the frontal sinus, visible on skull radiographs or CT, to compare AM and PM...
- Periapical Radiograph
- A dental radiograph showing the full length of one to three teeth, including roots and surrounding bone, from crown to apex. The...