A panoramic X-ray (PANO), also known as an Orthopantomogram (OPG), is a two-dimensional dental X-ray that captures a comprehensive view of the entire mouth in a single image. This specialized diagnostic tool provides a broad perspective of the teeth, upper and lower jaws, and surrounding anatomical structures. Unlike smaller intraoral X-rays that focus on one or two teeth, the PANO provides a flat image of the entire curved jaw structure. It gives dentists a complete overview of a patient’s oral and maxillofacial health, allowing for the detection of issues not visible during a standard clinical examination.
How the Panoramic X-ray Procedure Works
The process of taking a panoramic X-ray is non-invasive, as the imaging sensor is not placed inside the patient’s mouth. The patient typically stands or sits in the center of the panoramic machine, and their head is carefully positioned with chin, forehead, and side rests for stability. The patient is asked to gently bite down on a sterile plastic guide or bite block to ensure the teeth are correctly aligned and slightly separated, which helps create a clearer image of the dental arches.
Once the patient is correctly positioned, the machine’s X-ray tube and the sensor rotate in a synchronized semicircular motion around the patient’s head. The X-ray beam passes through the jaw area, and the sensor captures the data as the machine moves from one side of the jaw to the other. This rotation produces the single, continuous, wide-field image. The entire exposure process usually takes only about 12 to 20 seconds, and the patient must remain completely still during this brief period to prevent blurring the final image. This quick, extraoral method is often more comfortable for patients who have a sensitive gag reflex.
Unique Diagnostic Scope
The panoramic X-ray’s primary advantage lies in its extended field of view, capturing a vast area impossible to visualize with standard bitewing or periapical X-rays. While smaller X-rays offer high-resolution detail of individual teeth, the PANO provides a holistic view of the entire maxillofacial skeleton. It clearly displays the full length of the upper jaw (maxilla) and the lower jaw (mandible), including all existing teeth, developing teeth, and the surrounding bone structure.
This comprehensive image extends beyond the teeth to include structures such as the temporomandibular joints (TMJ) and the surrounding sinuses. Specifically, the maxillary sinuses and the nasal area are visible on the panoramic film. The resulting image is a two-dimensional representation of the horseshoe-shaped jaw, allowing dental professionals to assess the relationships between these structures. The broader scope enables the evaluation of conditions affecting the larger bones and joints.
Clinical Applications
The wide-ranging view provided by a PANO makes it a diagnostic tool used by general dentists, orthodontists, and oral surgeons for numerous clinical purposes. One of the most common reasons for ordering a panoramic X-ray is to evaluate the presence, position, and development of wisdom teeth, or third molars. This is especially helpful for assessing whether these teeth are impacted, which aids in surgical extraction planning.
Orthodontists rely on the PANO to assess overall jaw development and the alignment of the entire dentition before beginning treatment with braces or aligners. The image provides necessary information on the relationship between the upper and lower jaws and the presence of any unerupted permanent teeth. The PANO is also used for detecting asymptomatic pathologies, such as cysts, tumors, or infections located deep within the jawbone that would not be noticeable during a visual exam.
The image is also used to evaluate the extent of advanced periodontal disease by visualizing the overall bone level supporting all the teeth across the entire arch. For complex procedures, such as pre-surgical planning for dental implants or extensive extractions, the PANO allows the surgeon to assess the available bone height and identify the location of important anatomical landmarks, like the mandibular nerve canal and the maxillary sinuses.
Radiation Safety and Preparation
Modern panoramic X-ray machines utilize low doses of ionizing radiation, minimizing patient exposure while producing high-quality diagnostic images. The radiation dose from a single panoramic X-ray is comparable to the amount of natural background radiation a person receives over a few days. Safety protocols are followed to ensure that radiation exposure is kept as low as reasonably achievable.
Patients are provided with a lead apron to wear over their torso during the procedure, which protects radiosensitive tissues. To ensure the best image quality and avoid artifacts, patients are instructed to remove all metal objects from the head and neck region prior to the scan. This includes:
- Eyeglasses
- Jewelry such as earrings and necklaces
- Hairpins
- Removable dental appliances or hearing aids
These items can interfere with the X-ray beam and create “ghost images” on the final radiograph.