What is a panoramic jaw x-ray (panorex)?

What is a Panoramic Jaw X-ray (Panorex)?

A panoramic jaw x-ray, also called orthopantomography (OPT) or panorex, is a two-dimensional dental imaging technique that captures both the upper and lower jaws, all teeth, temporomandibular joints, and maxillary sinuses in a single image using rotational tomography combined with slit-beam radiography. 1

Technical Mechanism

• The panoramic radiograph is created through a fundamentally different process than standard projection radiographs (like bitewing or periapical x-rays), using curved surface tomography where the x-ray source and detector rotate synchronously around the patient's head 2
• This rotational technique produces a panorama-like view of the entire dentomaxillofacial region on one film 3, 4
• The image represents a complex projection with inherent limitations including tomographic blurring, magnification, distortion, secondary images, and reduced sharpness of detail compared to intraoral radiographs 3, 5

Clinical Advantages

• The primary advantage is visualization of structures over a large anatomical area in their relative spatial relationships, which is impossible with multiple smaller intraoral films 1, 6
• Panoramic imaging delivers approximately 10 times less radiation exposure than a complete intraoral radiographic series (full-mouth periapical series), with absorbed doses similar to bitewing radiography 1, 3
• The individual radiation risk is calculated at 1.3 × 10⁻⁶, which is relatively insignificant compared to other radiographic examinations 3

Appropriate Clinical Indications

According to national dental imaging guidelines, panoramic radiography is indicated for:

• Orthodontic diagnosis and treatment planning (in combination with lateral cephalometric radiography) 1
• Initial evaluation of suspected dental impaction, particularly for third molars 1
• Assessment of dental morphology anomalies, numeric anomalies (supernumerary or missing teeth), and tooth transposition 1
• Diseases of the maxillary sinus, particularly basal portions 4
• Jaw fractures (though with significant limitations—see below) 7
• Sialolithiasis, oral cavity tumors invading bone, osseous tumors, and facial anomalies 4

Critical Limitations and When NOT to Use Panoramic Radiography

• Panoramic radiography has only 86-92% sensitivity for mandibular pathology and will miss nondisplaced fractures, early osteomyelitis, and subtle bone changes 8, 7
• The technique provides poor visualization of the posterior mandible and has significant overlap with the cervical spine that obscures anterior regions 8
• For mandibular infections or suspected osteomyelitis, the American College of Radiology explicitly advises against relying on panoramic radiography alone, as CT maxillofacial with multiplanar reformations is nearly 100% sensitive and should be the primary imaging modality 8
• For jaw fractures, panoramic radiography misses nondisplaced and minimally displaced anterior fractures, and poorly visualizes mandibular condyle and subcondylar fractures with anterior displacement 7, 9
• Panoramic radiography provides no information about temporomandibular joint soft tissue components (disc, ligaments, capsule) and is insufficient for TMJ assessment 1
• The lower resolution compared to intraoral radiographs makes panoramic imaging inappropriate for routine periodic dental check-ups 6

Technical Requirements for Quality Images

• Meticulous patient positioning is absolutely essential to accommodate the jaws to the manufacturer-determined image layer 3
• Poor positioning will exacerbate the inherent distortions and superimpositions, significantly degrading diagnostic quality 3, 5
• Scrupulous assessment of the final radiograph for any pathological changes is mandatory to maximize diagnostic yield 3

When to Upgrade to Advanced Imaging

• When panoramic imaging shows canine inclination exceeding 30° or suspected root resorption of adjacent teeth, CBCT is justified as further examination 1
• For severe dysmorphoses, craniofacial syndromes, impacted teeth requiring detailed spatial relationships, bone anomalies, serious facial asymmetries, or condylar aplasia/hypoplasia, CBCT should be obtained instead 1
• For any suspected mandibular infection or fracture where surgical planning is needed, CT maxillofacial with multiplanar reformations should replace panoramic radiography 8, 7, 9