Dental Panoramic X-Ray

The dental panoramic radiograph (orthopantomogram, OPG) is a curved-plane tomographic image that displays the entire dentition, mandible, maxilla, temporomandibular joints and maxillary sinuses on a single film. It is a mainstay of dental and maxillofacial assessment, offering a broad overview at low dose, and is used for treatment planning, evaluating impacted teeth, and screening for jaw pathology. It complements, rather than replaces, intraoral films and CBCT/CT for detailed assessment.

Indications

General dental assessment and treatment planning
Evaluation of impacted or unerupted teeth (especially third molars) and their relationship to the inferior alveolar canal
Assessment of jaw cysts, tumours and other bony lesions
Suspected mandibular fractures and dentoalveolar trauma
Temporomandibular joint evaluation and pre-orthodontic assessment
Assessment of periodontal bone loss and periapical disease
Pre-implant and pre-extraction planning
Evaluation of the developing dentition in children

Contraindications & Cautions

No absolute contraindications
Pregnancy: very low dose but justify and use a thyroid collar/apron for reassurance
Patients unable to remain still or maintain the standing/seated position may produce non-diagnostic images
Low effective dose (~0.01 mSv) but apply ALARA, particularly in children
Not a substitute for intraoral periapical/bitewing films or CBCT where fine detail is required

Patient Preparation

Remove all metallic and radiopaque objects: earrings, necklaces, hairpins, glasses, dentures, hearing aids and piercings
Explain the rotating gantry and the need to remain completely still throughout the exposure
Position the patient with the chin on the rest, bite on the bite block, and the head aligned with the light beam guides (Frankfort plane horizontal, midsagittal plane vertical)
Instruct the patient to place the tongue against the palate to reduce the palatoglossal air-space artefact
Apply a thyroid collar where it does not obscure the field
Confirm pregnancy status where relevant

Technique & Parameters

Panoramic (rotational) tomography using a synchronised tube and detector moving around the head
Single continuous exposure of ~12-20 seconds producing a curved focal trough image
Typical exposure factors ~60-70 kVp with low mAs
Bite block and head positioning place the dental arches within the focal trough for sharp imaging
Correct positioning is essential; objects outside the focal trough are blurred or magnified
Supplement with intraoral films, occlusal views or CBCT/CT for detailed or three-dimensional assessment
Digital detectors are standard, allowing image manipulation and dose reduction

Systematic Review

Assess image quality and positioning (symmetry, occlusal plane, absence of blurring)
Systematically evaluate each tooth: crown, root, periapical region and count/eruption status
Assess alveolar bone levels and periodontal bone loss
Trace the mandibular cortical outlines, condyles, rami, body and inferior alveolar canals
Evaluate the maxilla, hard palate and both maxillary antra
Assess both temporomandibular joints for symmetry and morphology
Review for cysts, radiolucent or radiopaque lesions and retained roots or foreign bodies
Check the visible cervical spine, styloid processes and airway

Key Findings & Significance

An impacted third molar with its position and relation to the inferior alveolar canal (superimposition, loss of the canal cortical lines) affecting surgical risk
A well-defined pericoronal radiolucency around an unerupted tooth suggests a dentigerous cyst
A periapical radiolucency indicates chronic apical (periradicular) infection or granuloma/cyst
Horizontal alveolar bone loss indicates periodontal disease
A step or lucent line across the mandible indicates a fracture (frequently at the angle or condyle, often two sites)
A multilocular 'soap-bubble' lucency suggests ameloblastoma or odontogenic keratocyst
Loss of the mandibular cortex or focal lucency may indicate osteomyelitis, osteonecrosis (e.g. bisphosphonate-related) or metastasis
Antral opacification or a fluid level suggests maxillary sinusitis; an oroantral relationship of upper molar roots

Differential Considerations

Pericoronal radiolucency: dentigerous cyst, odontogenic keratocyst, ameloblastoma, hyperplastic follicle
Periapical radiolucency: apical granuloma, radicular cyst, apical abscess, early cemento-osseous dysplasia
Multilocular radiolucency: ameloblastoma, odontogenic keratocyst, central giant cell granuloma, aneurysmal bone cyst, myxoma
Radiopaque jaw lesion: odontoma, cemento-osseous dysplasia (mature), osteoma, condensing osteitis, tori
Mixed lesion: ossifying fibroma, calcifying odontogenic tumour, fibrous dysplasia
Ill-defined destructive lesion: osteomyelitis, medication-related osteonecrosis, osteoradionecrosis, metastasis/squamous cell carcinoma invasion
TMJ change: degenerative joint disease, condylar hypoplasia/hyperplasia, prior fracture

Pearls & Pitfalls

Positioning errors are the commonest cause of non-diagnostic OPGs; a reverse-smile occlusal line indicates chin tilted too high, an exaggerated smile too low
Ghost artefacts from objects on the opposite side appear higher, magnified and blurred - remove all jewellery and check for retained items
The palatoglossal air space over the maxillary tooth roots is a common artefact mimicking pathology; tongue-to-palate positioning reduces it
Mandibular fractures are often bilateral or paired - if one is seen, search for a second (especially condylar)
The panoramic image is geometrically distorted and cannot be used for accurate measurement; use CBCT for implant planning
The anterior region is prone to blurring if teeth are outside the focal trough
Superimposed cervical spine, hyoid and soft-palate shadows can mimic or obscure lesions

Structured Report

State image quality and any positioning limitations
Report the dentition, eruption/impaction status and any caries or periapical disease
Describe alveolar bone levels and periodontal status
Report jaw lesions with location, margin and internal appearance
Comment on the mandible (including condyles), maxilla, TMJs and maxillary antra
Impression: summarise significant findings and recommend intraoral films or CBCT/CT where further detail is needed

References

White SC, Pharoah MJ. Oral Radiology: Principles and Interpretation, Elsevier
SEDENTEXCT / European Commission Guidelines on Radiation Protection in Dental Radiology
FGDP(UK)/Royal College of Radiologists Selection Criteria for Dental Radiography
American Dental Association / FDA Dental Radiographic Examinations Recommendations
Whaites E, Drage N. Essentials of Dental Radiography and Radiology, Elsevier

Educational clinical decision support only. Protocols vary by institution and equipment; always confirm with a qualified radiologist and local guidelines before clinical use.

Dental Panoramic X-Ray

📋 Indications

⛔ Contraindications & Cautions

🧑‍⚕️ Patient Preparation

⚙️ Technique & Parameters

🔎 Systematic Review

🩻 Key Findings & Significance

🧠 Differential Considerations

💡 Pearls & Pitfalls

📝 Structured Report

📚 References