There are two general features that distinguish this panoramic from a poor one – they are adequate exposure and correct anatomic representation.
Adequate exposure – An assessment of adequate exposure implies that there is adequate density and contrast to recognize anatomic features.
Example of an overexposed panoramic image:
Example of an underexposed panoramic image:
Images demonstrating how inadequate exposure can lead to failure to detect pathologic features. This image on the right is a digitally enhanced version and clearly demonstrates the appearance of an impacted mandibular right third molar that was not readily apparent on the original (left). This enhancement also clearly demonstrates a large pericoronal pathology that seems to involve the right second mandibular molar.
Anatomically representative – A panoramic should be a good representation of the maxillofacial structures that it images. This means that there is adequate coverage of the osseous structures and that they are represented with some degree of accuracy. To determine correct anatomic representation, a visual assessment of the panoramic radiograph should be performed for accuracy of both anatomic structures and the dentition.
Panoramic anatomy – A reference for anatomic structures commonly observed on panoramic diagram appears below. Many of these structures are mentioned in the prior text and in the subsequent discussion of common errors.
|1. Mandibular Condyle||12. Cervical Vertebra||23. Genial Tubercles|
|2. Coronoid Process||13. Zygomatic Process||24. Nasal Concha|
|3. Nasopharyngeal Airspace||14. Incisive Foramen||25. External Oblique Ridge|
|4. Oropharyngeal Airspace||15. Mandibular Foramen||26. Angle of the Mandible|
|5. Styloid Process||16. Mandibular Canal Space||27. Zygomatic Bone|
|6. Lateral Pterygoid Plate||17. Soft Palate||28. Glenoid Fossa|
|7. Zygomatic Arch||18. Hyoid Bone||29. Inferior Border of the Mandible|
|8. Articular Eminence||19. Hard Palate||30. Palatoglossal Airspace|
|9. Anterior Nasal Spine||20. Nasal Septum||31. Pterygomaxillary Fissure|
|10. Mental Foramen||21. Maxillary Sinus Floor||32. Maxillary Tuberosity|
|11. Infraorbital Canal||22. Nasal Fossa||33. Zygomaticotemporal Suture|
Features of the Dentition – Several visual features of the dentition can be used to assess whether the teeth, particularly the anterior teeth are positioned correctly within the focal trough: