Dental imaging: bitewing, periapical, panoramic and CBCT
- Examination
Each dental image answers a different question: decay between teeth, the root tip, the whole jaw, or a 3D view before surgery.
See it in 3D: Mandible · Maxillae · Maxillary sinus · TMJ disc
What it is
Most dental radiographs are small intraoral films with a very low dose. Bitewings show the crowns of the upper and lower back teeth together and are best for decay between teeth and for the bone level. Periapical films show a whole tooth to the root tip and the surrounding bone. The panoramic radiograph (orthopantomogram) shows both jaws, all the teeth, the TMJs and the maxillary sinuses in one image. Cone-beam CT (CBCT) gives three-dimensional images of the jaws for implants, impacted teeth, cysts and nerve relations, at a higher dose. Ultrasound and medical CT or MRI are used for soft-tissue and deep-space infections.
Findings and interpretation
- Caries and periapical lesions appear radiolucent (dark) because mineral has been lost.
- A periapical lesion becomes visible only after a substantial amount of bone has been lost, so early infection may not show.
- Horizontal or vertical bone loss between teeth indicates periodontitis.
- A well-defined radiolucency around the crown of an unerupted tooth suggests a dentigerous cyst.
- Pregnancy is not a contraindication to necessary dental radiographs with a lead collar and thyroid shield; elective films can wait.
How it is done
- Ask what question the image must answer before choosing it.
- Bitewing: caries between back teeth, early bone loss.
- Periapical: root, periapical lesion, root fracture, length of a root canal.
- Panoramic: overview of both jaws, development and eruption in children, fractures, cysts, third molars.
- CBCT: 3D detail before implants or third-molar surgery, or to characterise a jaw lesion.
- Contrast-enhanced medical CT: suspected deep neck infection or spread from a dental abscess.
Common mistakes
- Ordering a panoramic film to look for small caries misses them; bitewings are needed.
- A normal radiograph does not exclude an acute abscess in its first days.
- Mandibular condyle fractures are easily missed on a single view; a panoramic film or CT shows them better.
Next step / Initial management
- Choose the image by the clinical question and keep to the lowest dose that answers it.
- Jaw radiolucency found by chance: refer to the dentist or oral surgeon; growing, painful or nerve-related lesions need prompt referral.
- Suspected deep space infection: contrast CT of the neck rather than dental films, with urgent surgical referral.
Test yourself
Think of the answer, then tap the question to see it.
Which dental radiograph is best for decay between back teeth?
The bitewing radiograph.
Why can a periapical abscess be invisible on an early radiograph?
Because bone must lose a substantial amount of mineral before the lesion becomes radiolucent.
What imaging is needed for a suspected deep neck infection of dental origin?
Contrast-enhanced CT of the neck.
Connections
See it in 3D4
The structures of Durgical's 3D anatomy where it is found.
Educational content; it does not replace assessment by a dentist or doctor and is not a clinical instruction. For facial or neck swelling with difficulty swallowing or breathing, a knocked-out tooth or bleeding that will not stop, go to an emergency department at once.
Sources: Dental Cone Beam Computed Tomography (StatPearls Publishing (NCBI Bookshelf), 2023); Dental Caries Diagnostic Testing (StatPearls Publishing (NCBI Bookshelf), 2023); Mandible Fracture (StatPearls Publishing (NCBI Bookshelf), 2023).
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Representative model, for educational purposes only.