Introduction:
Panoramic X-ray or panoramic radiography, is a two-dimensional (2-D) dental X-ray technique that captures the entire oral cavity in a single image, covering the teeth, upper and lower jaws, surrounding tissues, and other structures. Dentists and oral surgeons commonly prefer this imaging technique in day-to-day practice as it aids in planning treatment for braces, dentures, extractions, and implant placement. A panoramic X-ray examination is fast, painless, and easy to perform. It may be recommended instead of intraoral X-rays in patients who have a sensitive gag reflex.
How Does Panoramic Radiography Help Detect Head and Neck Pathologies?
Panoramic radiography or in short, OPG (orthopantomogram) in dentistry refers to the radiological technique that gives an insight into the overview of the jaw structures mainly the adjacent structures surrounding the dentition, except the soft tissues. The entire dentition which covers both the upper and the lower jaw can be viewed in panoramic radiography. In comparison to panoramic radiography, which is a 2-D dental X-ray technique, recently emerging cone-beam computed tomography (CBCT) holds promising potential in all oral and maxillofacial surgical procedures. It is also helpful in the pre-evaluation of implantology procedures since it is a three-dimensional (3D) radiographic modality.
Panoramic imaging not only helps in the imaging of dental structures but is also useful in the careful and possible detection of head and neck pathologies. Various anatomic alterations or variations that can give the dentist or the maxillofacial surgeon a hint of any systemic issues or diseases in the head and neck region, can be picked up by panoramic radiography, hence proving it to be highly beneficial in the detection of head and neck pathologies.
Also, many asymptomatic patients with head and neck lesions may not notice the change in features since most lesions may be slow-growing. These can be identified when one undergoes routine or random panoramic imaging. This article casts light on common systemic alterations that could contribute to clinical or general health complications, which can be detected through oral panoramic radiography.
General dentists and maxillofacial surgeons have a good understanding of how systemic lesions can be linked to oral lesions and vice versa and are also well-trained in recognizing the same. This means that dentists can easily observe these abnormal variations or alterations in the head and neck anatomy on panoramic radiographs. If needed, they can further request additional clinical examination by the general physician to rule out systemic abnormalities. If any abnormality is suspected, then the patient can be referred to a suitable specialist. For further diagnosis and confirmation, advanced radiographic imaging like CBCT or multidetector CT (computed tomography) scanning may also be suggested in case of any advanced lesions.
What Are the Common Head and Neck Pathologies That Can Be Diagnosed Through Panoramic Imaging?
Though 2D panoramic radiography or the OPG would have its fair share of radiographic drawbacks such as image-based errors, overlapping issues, or radiographic artifacts, they can still be beneficial in diagnosing both oral and some systemic lesions. The following are a few pathologies that can be diagnosed through panoramic imaging:
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Tonsilloliths: Dental panoramic radiography can detect the presence of tonsilloliths or tonsil stones. These are usually incidental findings and are identified when the tonsillolith lesions are large. Because of the 2D limitations of panoramic radiography, the exact location of the tonsilloliths may be difficult to trace.
In that case, if the dentist suspects a possible presence of tonsilloliths, they can suggest taking a cone-beam computed tomography scan (CBCT) in order to accurately assess the correct position of these radiographically observable calcifications. Further, panoramic radiography aids in the removal of large tonsilloliths by the dentist or oral surgeon and helps prevent associated complications like chronic infection, pain, or abnormalities in swallowing.
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Sialoliths: Sialoliths or salivary gland stones, are observed as rather elliptical or elongated calcifications that form in any of the salivary glands and are quite frequently reported by dental surgeons during panoramic radiography. These can also be identified alternatively on occlusal radiography and can be beneficial in preventing recurrent pain or swelling which usually occur in the major or minor salivary glands.
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Phlebolith: Phlebolith refers to a small, calcified blood clot that forms in a vein. These can be identified radiographically during panoramic imaging as a radiopaque, rounded, or oval opacity that usually measures more than 0.23 inches in diameter, possessing a homogeneous radiopacity rather than a uniform periphery. Detection of phlebolith on panoramic imaging can be important in diagnosing diseases like oral, mucosal, or submucosal venous malformations. Further, they may also be indicative of any underlying systemic condition for which the dentist needs to refer the patient to a general physician.
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Facial Artery Calcifications: In fact, panoramic radiography is known to be one of the first major auxiliary in detecting abnormalities in the facial artery which is most common in patients undergoing hemodialysis (a treatment that filters salts, waste, and fluids from the blood when the kidneys can no longer function properly). These calcifications can be seen in other systemic diseases of the head and neck as well when the calcium gets deposited within the arterial walls becomes significant to the arterial contour and can manifest as thin parallel radiopaque lines on panoramic radiography outlining the facial artery.
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Triticeous Cartilages and Calcified Carotid Atheromas: These are the lesions associated with the greater horn of the hyoid bone and superior horn of the thyroid cartilage of the neck (triticeous cartilage) that present as a well-defined and well-shaped oval opacity with a smooth and corticated periphery or border.
This lesion needs to be differentiated from other calcifications that commonly manifest in the internal carotid artery or the neck that is, the calcified carotid atheromas. Atheromas of the internal carotid artery can easily manifest in patients suffering from diabetes mellitus (a group of diseases that affects how the body utilizes blood sugar or glucose), systemic hypertension (high blood pressure), or in patients suffering from hyperlipidemia (high cholesterol). Panoramic radiography holds special importance not only in differentiating these two closely approximate radiographic lesions, but research also demonstrates that almost 30 percent of post-menopausal women have a high risk of developing internal carotid disease or calcification that can lead to ischemic attacks or put one at a higher risk of acquiring cardiovascular stroke. When these calcifications in the internal carotid do not present with any clinical features, panoramic radiography done during routine dental examination can be useful in alerting the patients.
Conclusion:
To conclude, be it symptomatic or asymptomatic routine detection of lesions on a dental panoramic imaging or radiograph, dentists and oral surgeons are usually trained in recognizing these possible systemic lesions that can manifest commonly as dental, muscular, oral, facial, sinus, or pharyngeal pain. Further, because oral diseases are linked to systemic diseases and vice versa, panoramic radiography proves to be a valuable asset in dentistry as it is a cheap and effective imaging modality that can detect lesions of the head and neck, apart from diagnosing dental lesions.
