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The Premier Dental Radiology Experience

Periapical and Bitewing Radiopacities

Dr. Barett Andreasen, Oral and Maxillofacial Radiologist

Radiopacities will occasionally appear on a periapical or bitewing. This list of radiopacities that you may encounter serves as a starting point for your differential. It is not an exhaustive list but covers the vast majority of entities you will encounter as a dental professional. For radiopacities that are specifically at or near the root apex, please see our 'Apical Radiopacities' graphic.

 

Antrolith

Antroliths

Antroliths appear as a calcified mass within the maxillary sinus separated from the adjacent sinus floor. Antroliths are often formed in the environment of chronic sinusitis and may originally calcify from a nidus of inflamed mucus, pus, clots or foreign bodies.

Antroliths present as a well-defined calcified mass, ranging from a faint to dense radiopacity with a laminated appearance, which may be difficult to appreciate on periapicals. They are roughly spherical or ovoid in shape and may be solitary or multiple in number.

No treatment for the antroliths themselves is necessary, if asymptomatic. However, the underlying cause for possible chronic sinusitis may need to be addressed. Treatment for chronic sinusitis can range from simple antibiotics to sinus surgery. Fungal sinusitis (aspergillosis) should be considered in cases that are unresponsive to therapy.

 

Osteomas

Osteomas

Osteomas are benign neoplasms of bone that can involve any part of the skeleton but are more commonly present in the craniofacial region. While more often found in the frontal and ethmoid sinuses, maxillary osteomas (sometimes called antral exostoses) can appear along the floor of the sinus in periapical radiographs. Radiographically, they appear as bony projections with a pedunculated, almost mushroom-like appearance. Other osteomas may have a broader, sessile base. The primary distinction between osteomas and antroliths is the relationship to the walls and floor of the sinuses - osteomas are directly connected to the floor or a wall of the sinus whereas antroliths are entirely separate from the floor of the sinus and are often 'floating' in thickened mucosa. On 2D imaging, osteomas often appear as homogenously dense radiopacities, though 3D radiography can reveal a more heterogenous (cancellous) center in some osteomas.

Generally osteomas are no cause for concern and require no treatment as long as the patient is asymptomatic and no sinus issues occur. However, when multiple osteomas are noted, the possibility of Gardner Syndrome should be ruled out.

 

Sialolith

Sialoliths

Formation of a mineralized mass within the salivary glands or ducts is termed a sialolith (salivary stone). Sialoliths arise from calcium deposits that form around a nidus within the duct lumen. Of the major salivary glands, the submandibular gland is most often involved, likely due to the upward and tortuous nature of the submandibular duct as well as its thicker, mucoid secretions.

On bitewings and periapicals, sialoliths present as a well-defined radiopacity that ranges from completely radiopaque to mixed-density in appearance. A lamellar or 'onion'-like appearance may be evident, reflecting the chronic and repeated deposition of calcium that forms these entities. Sialoliths are normally spherical or oval with smooth borders, but can be elongated if within a duct.

Patients may present with a history of recurrent swelling and/or pain during mealtimes, though many cases are asymptomatic. Stimulation of salivary flow, hydration, massage and moist heat can often dislodge smaller sialoliths. Larger stones may require surgical intervention, such as excision or sialoendoscopy.

 

Mucositis (https://pocketdentistry.com/20-inflammatory-disease/)

Mucositis/Mucosal thickening

When the root apices of maxillary posterior teeth project through the maxillary sinus floor, apical periodontitis involving these teeth may produce a localized mucosal tissue edema termed periapical mucositis. This thickened mucosa can be evident on periapicals of the posterior maxillary teeth and appears as a soft tissue expansion (less radiopaque than bone) directly adjacent to the infected root apex.

Additionally, sinogenic mucosal thickening may be present along the floor of the maxillary sinuses. Mucosal thickening is not associated with apical inflammation but rather is due to localized inflammation within the sinus itself. This may be due to factors such as allergies, pollution, the common cold, dust or other conditions. The appearance of mucosal thickening is the same as mucositis - soft tissue density thickening at the floor of the sinus - but again is not of dental origin.

Neither mucositis nor mucosal thickening require treatment, though the offending tooth associated with the mucositis should obviously be addressed.

 

Mucous Retention Pseudocyst

Mucous Retention Pseudocyst

Mucous retention pseudocysts occur when submucosal mucinous glands within the paranasal sinuses become obstructed. This leads to an accumulation of fluid beneath the sinus mucosa and results in a swelling of the tissue.

The radiographic appearance of mucous retention pseudocysts is described as a dome-shaped radiopacity along the floor or wall of a sinus. The borders are well-defined and smooth but lack cortication. This is an important distinction as it helps distinguish mucous retention pseudocysts from pathology arising from the adjacent bone.

Mucous retention pseudocysts have no effect on the surrounding structures and as such, the borders of the involved sinus should always remain intact and without any expansion or displacement. If the pseudocyst is superimposed over the roots of a tooth, the lamina dura and PDL space should be unaffected.

No treatment is typically necessary for mucous retention pseudocysts as they normally cause no symptoms and resolve spontaneously without any surgical intervention.

 

Tori (https://doi.org/10.1016/S1061-3315(02)00012-4)

Tori

Tori are outgrowths of bone typically composed of dense cortical bone arising from the buccal or lingual surfaces of the alveolar bone. These entities are often evident clinically and range from barely palpable masses to large bilateral outgrowths that contact near the midline.

Tori can be noted on periapical and bitewing radiographs and often appear as a ovoid radiopacity at or just apical to the alveolar crest. Most often, tori that appear on radiographs are located lingual to the mandibular premolars but maxillary tori can be seen as well.

Treatment for tori is unnecessary if asymptomatic (the thin mucosa over the tori is susceptible to trauma) and if removal is not needed for any planned prosthesis.

 

Osteoma Cutis (Case courtesy of Dr. Caroline Latta)

Osteoma Cutis

Osteoma cutis represents the formation of small calcified nodules in the facial skin. Approximately 85% of cases occur as a result of acne of long duration, developing in a scar or chronic inflammatory traumatic or neoplastic dermatosis. Cases of osteoma cutis are benign, noninvasive and typically asymptomatic in nature, though larger lesions may be palpated.

Osteoma cutis may occasionally be present on 2D imaging, most often on posterior bitewings. These cases typically present with multiple small, washer-shaped radiopacities in the soft tissues of the face. The internal structure may be radiolucent or more radiopaque depending on the degree of calcification.

No treatment is required but lesions may be removed due to cosmetic concerns.

 

Sclerotic healing (Diagnostic Imaging Oral and Maxillofacial - Lisa Koenig)

Sclerotic Healing of an Extraction Site

Occasionally after the extraction of a tooth, dense sclerotic bone will fill either a portion or the entirety of the extraction site where normal cancellous bone was to be expected. This process, sometimes called 'socket sclerosis', has been theorized to be caused by disturbances in metabolic balances, though others consider this sclerotic healing to be synonymous to idiopathic osteosclerosis. Graft material may also cause extraction sites to appear more sclerotic. This finding generally goes unnoticed clinically because there are typically no signs or symptoms associated with socket sclerosis.

Depending on the appearance, sclerotic healing of an extraction site may be confused with a retained root tip. This distinction is especially difficult when healing of the socket is not yet complete and a band of radiolucent immature bone resides in the middle of the site, potentially mimicking a root canal.

As sclerotic healing of extraction sites are typically asymptomatic, no treatment is necessary.

 

Enamel Pearl (https://www.methuenperio.com/clinical-cases/)

Enamel Pearl

The enamel pearl is a small formation of enamel approximately 1-3mm in diameter that occurs on the roots of molars. Most enamel pearls develop in the furcal areas of molar teeth, often at or just apical to the CEJ. Enamel pearls appear as smooth, round radiopacities, often with the same density of enamel found within the crown of the tooth.

No symptoms are typically associated with enamel pearls; however, depending on the location, enamel pearls may predispose to formation of a periodontal pocket and subsequent periodontal disease. Removal may be needed if this is the case.

Cemental Tear

Cemental Tear

A cemental tear is a special type of surface root fracture that may cause periodontal and/or periapical bone destruction. In a cemental tear, a layer of cementum is separated from the underlying root dentin as a result of excessive occlusal forces or trauma to the jaws. This sheared-off fragment remains within the periodontal ligament and acts as a constant irritant. On radiographs, this appears as a linear radiopacity that parallels the adjacent root surface. While usually completely separate, some fragments may remain attached to the root surface.

Cemental tears can present as part of apical periodontitis but can also occur independently with a vital pulp. Soft tissue swelling, localized periodontal pocket, periodontal/periapical bone loss are noted clinical characteristics of cemental tears.

Treatment options include nonsurgical scaling and root planing, surgical debridement with periodontal/apical surgery, surgical debridement combined with GTR and bone grafting, and extraction.

 

Arteriosclerosis

Arteriosclerosis

Degeneration and eventual loss of elastic fibers followed by deposition of calcium salts in the medial layer of an artery results in a condition called arteriosclerosis. This condition, also called Monckeberg's medial calcific sclerosis, which leads to a reduction in vessel elasticity and compliance. These calcifications can be seen involving the facial artery and the branches of the maxillary artery and may be imaged by bitewing and panoramic radiographs.

Calcifications of arteriosclerosis appear as 'train-track' radiopacities that follow the course of the artery. No treatment is needed for arteriosclerosis; however, correlation with the patient's medical history is highly recommended as these findings are typically noted in patients with uncontrolled diabetes and chronic renal disease.

A Word of Caution

There are, as always, exceptions to these rules. As anyone who practices in the field of dentistry knows, nothing ever quite follows the textbooks, especially when delving into the field of pathology and radiology. The entities covered above demonstrate many various presentations and manifestations which cannot be covered in this article, and that's not to mention the numerous pathologies which were not discussed.

If you have any questions about a radiograph, please send your case to Radiodontics by using the 'Upload Case' button at the top of the page to have your images be reviewed by an oral and maxillofacial radiologist.

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Panoramic Radiopacities

Dr. Barett Andreasen, Oral and Maxillofacial Radiologist

Radiopacities on a panoramic radiograph occur relatively infrequently but when they do appear, superimposition of anatomical structures and the inherent 2D nature of panoramic imaging makes localization and diagnosis of these radiopacities challenging. A proper understanding of the common radiopacities found on panoramic radiographs is critical to ensure appropriate management of patients.

 

Antroliths

Antroliths appear as a calcified mass within the maxillary sinus separated from the adjacent sinus floor. Antroliths are often formed in the environment of chronic sinusitis and may originally calcify from a nidus of inflamed mucus, pus, clots or foreign bodies.

Antroliths present as a well-defined calcified mass, ranging from a faint to dense radiopacity with a laminated appearance. They are roughly spherical or ovoid in shape and may be solitary or multiple in number. Antroliths may also appear in periapical radiographs of the posterior maxillary teeth.

No treatment for the antroliths themselves is necessary, if asymptomatic. However, the underlying cause for possible chronic sinusitis may need to be addressed. Treatment for chronic sinusitis can range from simple antibiotics to sinus surgery. Fungal sinusitis (aspergillosis) should be considered in cases that are unresponsive to therapy.

 

Tonsilloliths

Tonsilloliths (tonsil stones) are clusters of calcifications that arise in the tonsillar crypts of the palatine tonsils. These dystrophic calcifications are formed secondary to condensed necrotic debris and bacteria and can be found in a wide population, although they are more common in older age groups.

Tonsilloliths appear as single or multiple small, round or irregularly shaped radiopacities. On panoramic radiographs, they are typically found superimposed over the mid-ramus or located just posterior and inferior to the mandible in the region of the dorsal surface of the tongue. Tonsilloliths may be unilateral or bilateral.

No intervention is required if the patient is asymptomatic. However, tonsilloliths can promote recurrent tonsillar infections and may lead to soreness, dysphagia, halitosis, or other symptoms. In these cases, patients may attempt removal by gargling warm salt water, though curettage or local excision may be required if home treatment is unsuccessful.

 

Sialoliths

Formation of a mineralized mass within the salivary glands or ducts is termed a sialolith (salivary stone). Sialoliths arise from calcium deposits that form around a nidus within the duct lumen. Of the major salivary glands, the submandibular gland is most often involved, likely due to the upward and tortuous nature of the submandibular duct as well as its thicker, mucoid secretions.

On panoramic radiographs, sialoliths present as a well-defined radiopacity that ranges from completely radiopaque to mixed-density in appearance. A lamellar or 'onion'-like appearance may be evident, reflecting the chronic and repeated deposition of calcium that forms these entities. Sialoliths are normally spherical or oval with smooth borders, but can be elongated if within a duct. Solitary sialoliths are seen most frequently; however, multiple stones may be seen involving the parotid gland and can mimic calcified lymph nodes (such as might occur in tuberculosis).

Patients may present with a history of recurrent swelling and/or pain during mealtimes, though many cases are asymptomatic. Stimulation of salivary flow, hydration, massage and moist heat can often dislodge smaller sialoliths. Larger stones may require surgical intervention, such as excision or sialoendoscopy.

 

Lymph Node Calcifications

Calcification of lymph nodes results from chronic inflammation, either caused by a prior or active disease process. Calcified lymph nodes are most commonly seen in patients with tuberculosis, fungal infections, sarcoidosis, systemic sclerosis, lymphoma treated with radiation therapy, and malignancies (such as metastatic thyroid carcinoma).

Lymph node calcifications appear as radiopacities with well-defined and irregular borders. Most often the shape is described as having a lobulated or cauliflower appearance with the internal structure demonstrating a varying degrees of radiopacity. Other times, the presentation is more lamellar, making it difficult to distinguish them from sialoliths. The calcifications may involve a single node or a linear series of nodes, known as "chaining."

Calcified lymph nodes are usually found at or near the inferior and posterior borders of the mandible and may be superimposed over the mandible itself.

No treatment is indicated, as calcified lymph nodes are usually asymptomatic. However, the causative disease should be identified with a thorough review of the patient's medical history to rule out an active disease process.

 

Carotid Artery Calcifications

Atherosclerosis is characterized by the deposition of carotid artery plaques along the inner walls of the arteries. During the evolution of these plaques, dystrophic calcifications may develop which can be observed in panoramic radiographs.

Carotid artery calcifications usually appear as irregular, heterogenous radiopacities. They can be single or multiple and demonstrate a vertical linear distribution. Carotid artery calcifications are observed in the area of the carotid artery bifurcation, which is located adjacent to the third and fourth cervical vertebrae and near the greater cornu of the hyoid bone.

Carotid artery calcifications be mistaken for triticeous and thyroid cartilage calcifications. Triticeous and thyroid cartilage calcifications demonstrate a more uniform size, shape and location, which helps distinguish them from carotid artery calcifications.

If not currently being treated, patients with carotid artery calcifications should be referred to their physician for further cardiovascular and cerebrovascular examination as early identification and medical intervention reduces the risk of vascular events.

 

Phleboliths

Phleboliths (vein stones) are calcified thrombi most often associated with vascular malformations or hemangiomas. They form due to stagnation or disruption of normal blood flow within a vessel which causes the mineralization of a thrombi into a calcified mass.

Phleboliths are round or oval in shape with a smooth periphery and will often demonstrate a 'target-like' or laminated appearance, consisting of alternating layers of radiolucency and radiopacity. Multiple phleboliths in a random distribution is a common finding.

As phleboliths usually accompany vascular malformations, patients with phleboliths identified on their radiographs should be referred to their physicians for further assessment (if patient hasn't already received treatment). Proper management of vascular malformations is needed as lesions can undergo periods of rapid growth with infiltration and destruction of adjacent tissues. Vascular malformations also pose a risk of severe and even fatal hemorrhage, which may occur spontaneously or during surgical manipulation, such as during incisional biopsies or extractions of adjacent teeth.

 

Mucous Retention Pseudocyst

Mucous retention pseudocysts occur when submucosal mucinous glands within the paranasal sinuses become obstructed. This leads to an accumulation of fluid beneath the sinus mucosa and results in a swelling of the tissue.

The radiographic appearance of mucous retention pseudocysts is described as a dome-shaped radiopacity along the floor or wall of a sinus. The borders are well-defined and smooth but lack cortication. Mucous retention pseudocysts have no effect on the surrounding structures and as such, the borders of the involved sinus should always remain intact and without any expansion or displacement. If the pseudocyst is superimposed over the roots of a tooth, the lamina dura and PDL space should be unaffected. Mucous retention pseudocysts may also be evident on maxillary posterior periapical radiographs.

No treatment is typically necessary for mucous retention pseudocysts as they normally cause no symptoms and resolve spontaneously without any surgical intervention.

 

Stylohyoid Ligament

The stylohyoid ligament is a fibrous band that runs from the styloid process of the temporal bone and inserts into the lesser horn of the hyoid bone. Ossification of this ligament can occur and is a common incidental finding in panoramic radiographs.

Small ossifications of the stylohyoid ligament present as a uniform, linear radiopacity with larger ossifications usually demonstrating a denser, more radiopaque periphery with a less radiopaque internal structure. The ossification is normally seen as an elongation of the stylohyoid process; however, it may instead originate from the lesser horn of the hyoid bone or can even begin in a central area of the ligament. Borders are typically smooth and straight, but in some cases surface irregularity may be seen. More extensive ossifications can demonstrate segmentations or pseudoarticulations.

The vast majority of patients with ossification of the stylohyoid ligament are asymptomatic and require no treatment. When symptoms such as headaches, pain while swallowing, turning the head or opening the mouth, dysphagia, visual disturbances, or foreign body sensation in the pharynx are present, Eagle syndrome and carotid artery syndrome should be considered. Eagle syndrome is reserved for symptoms related to a recent history of neck trauma (typically tonsillectomy) while carotid artery syndrome is preferred when the above clinical findings are present without a history of neck trauma. The severity of symptoms is often unrelated to the degree of ossification present.

 

Thyroid/Triticeous Cartilages

Beginning at skeletal maturity, the hyaline laryngeal cartilages (the thyroid, triticeous, cricoid and arytenoid cartilages) undergo endochondral calcification and ossification. This process is a normal physiological change and continues throughout the patient's life. Occasionally, the calcification of the thyroid and triticeous cartilages can be seen on panoramic radiographs.

The triticeous cartilages present as paired small, well-defined, smooth, round or ovoid radiopacities inferior to the greater horn of the hyoid bone and superior to the superior horn of the thyroid. Calcified triticeous cartilages often are homogenously radiopaque but depending on the degree of calcification may demonstrate a identifiable peripheral cortex.

The superior horn of the thyroid cartilage can also be evident on panoramic radiographs, appearing medial to the C4 vertebra. The appearance varies with the degree of calcification, ranging from a faint incomplete outline to a distinct corticated border with a less dense internal structure.

As these are normal physiological changes, no treatment is needed for calcified thyroid and triticeous cartilages. Careful examination is advised to distinguish between calcified laryngeal cartilages and carotid artery calcifications.

A Word of Caution

There are, as always, exceptions to these rules. As anyone who practices in the field of dentistry knows, nothing ever quite follows the textbooks, especially when delving into the field of pathology and radiology. The entities covered above demonstrate many various presentations and manifestations which cannot be covered in this article, and that's not to mention the numerous pathologies which were not discussed.

If you have any questions about a radiograph, please click on the 'Upload Case' button below to have your images be reviewed by an oral and maxillofacial radiologist.
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Apical Radiopacities

Dr. Barett Andreasen, Oral and Maxillofacial Radiologist

This article serves as a review for the various radiopacities that are associated with the apices of mandibular and maxillary teeth. While this is by no means a complete and comprehensive list, these are the more common entities that will be encountered in the practice of dentistry.

Cemento-osseous dysplasia

Cemento-osseous dysplasia is a replacement of the normal trabecular bone with fibrous tissue and cementum-like/abnormal bone.  It begins as a well-defined radiolucency associated with the apices of teeth and as the lesion matures, radiopacities (often crescent-shaped) begin to appear around the tooth apex.  Late stage lesions present as dense radiopacities with a radiolucent border surrounding it.  There is often a periphery of sclerotic bone of varying width that may appear as a cortical outline. When cemento-osseous dysplasia directly involves the teeth, the lamina dura may be lost and the PDL space will either appear normal, widened or may be lost as well; however, the involved teeth remain vital, so please don't confuse an early lesion for periapical inflammation! If the lesion is large enough to involve the adjacent cortices, thinning and expansion of the cortices may occur.

There are three different variants of cemento-osseous dysplasia: focal, periapical, and florid. Focal cemento-osseous dysplasia involves a single site, typically in the posterior mandible. Periapical cemento-osseous dysplasia predominately affects the periapical region of the anterior mandible. Extensive forms of cemento-osseous dysplasia affecting 3 or more quadrants or widespread involvement in one jaw is termed florid cemento-osseous dysplasia.

An important fact in diagnosing cemento-osseous dysplasia is that it has a marked predilection for middle-aged to older black or Asian females.

No biopsy or treatment is indicated. However, regular radiographic follow-up (approximately every 12 months) is recommended to assess maturation of the lesion(s) and to monitor for simple bone cyst formation and secondary infection.

 

Condensing osteitis

As the name suggests, condensing osteitis is a bony proliferation in response to inflammation and will therefore only be found at the apex of non-vital teeth (-itis = inflammation). This process appears as an irregularly-shaped sclerosis with a widened PDL space or periapical radiolucency between the root and the area of sclerosis. The sclerotic bone may remain after treatment of the inflammation and is termed as osteosclerosis or a bone scar. The key take away is that condensing osteitis is only associated with pulpal inflammation, while the other entities which may appear similar (idiopathic osteosclerosis, cemento-osseous dysplasia, hypercementosis, and cementoblastoma) are associated with vital teeth.

 

Idiopathic osteosclerosis

Also known as a dense bony island, enostosis, or hyperostosis, this finding is of unknown etiology and typically occurs in the posterior mandible. While often associated with the root apices of mandibular molars and premolars, it can be found anywhere within the jaws. Idiopathic osteosclerosis presents as a dense, homogenous radiopacity with an amorphous shape. When associated with a root, a regular PDL space is maintained and the tooth is vital. On a CBCT, it will blend into adjacent cortices with no thinning or expansion. These features help differentiate idiopathic osteosclerosis from similar entities such as condensing osteitis, cemento-osseous dysplasia, hypercementosis, and cementoblastoma. No treatment is necessary for areas of idiopathic osteosclerosis.

 

Hypercementosis

Hypercementosis, as the name implies, is the buildup of excess cementum on the root surfaces. This deposition of cementum typically occurs within the apical third on posterior mandibular teeth and may give the root a 'bulbous' appearance. Though the appearance is unusual, the tooth is vital and the PDL space and lamina dura will remain regular and continuous around the areas of hypercementosis. The exact etiology is unknown; however, it's theorized to be a response to unstable or changing occlusion. Conditions such as Paget's disease, hyperpituitarism and Gardner syndrome should be ruled out if the hypercementosis is generalized. No treatment is necessary; however, extractions of teeth with hypercementosis may prove to be more difficult due to the bulbous shape of the roots.

Cementoblastoma

A cementoblastoma is a benign odontogenic neoplasm of cementoblasts and cementum and is seen most frequently involving the mandibular premolars or first molars of young adults. Cementoblastomas appear as a well-defined radiopacity or mixed density lesion with an amorphous or spoke-wheel pattern attached to and surrounding the root of a vital tooth. The outline of the roots are usually obscured and external root resorption may be seen as well. Pain and swelling can also be present. Suspected cementoblastomas should be biopsied and sent for pathological evaluation.

 

A Few Tips

The most reliable way to distinguish between these several entities is to look at the relationship between the lesion and the lamina dura, the PDL space, and the root. Each lesion :

  • Cemento-osseous dysplasia often causes loss of the lamina dura and the PDL may be normal, widened, or lost as well.
  • Condensing osteitis is associated with PDL space widening or a periapical radiolucency.
  • Idiopathic osteosclerosis will maintain a normal PDL space.
  • Hypercementosis is contained within the lamina dura and PDL space, which are normal.
  • Cementoblastomas are attached directly to the root and often obscures the root itself.

Vitality testing can also be performed on teeth with apical radiopacities to assist in diagnosis. All the entities above are associated with vital teeth with the exception of condensing osteitis. It's an easy one to cross off the list once you confirm tooth vitality.

A Word of Caution

There are, as always, exceptions to these rules. As anyone who practices in the field of dentistry knows, nothing ever quite follows the textbooks, especially when delving into the field of pathology and radiology. The entities covered above demonstrate many various presentations and manifestations which cannot be covered in this article, and that's not to mention the numerous pathologies which were not discussed.

If you have any questions about a radiograph, please click on the 'Upload Case' button below to have your images be reviewed by an oral and maxillofacial radiologist.

Apical Radiopacities
Cemento osseous Dysplasia
Condensing Osteitis
Idiopathic Osteosclerosis
Hypercementosis
Cementoblastoma
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A 'Sweet' Case

Dr. Barett Andreasen, Oral and Maxillofacial Radiologist

An incidental finding on a CT lingual to the mandibular anterior teeth. What is your diagnosis?

While we may be concerned about the presence of a tumor or neoplasm (and rightly so from the single image we have), there's actually no lesion here.  What we are seeing is a foreign object or more specifically, a lemonhead (a type of hard candy).

Foreign objects, especially comestible items like gum, chewing tobacco, and candy, can cause a surprisingly difficult diagnostic challenge. While patients are asked to removed all items from their mouth, patients may not comply and these objects are then captured in the radiographs.  Foreign objects can mimic the appearance of intraoral pathology and can lead to misdiagnosis, unnecessary radiation, and avoidable patient distress.  Compare this lemonhead to the second included image of a solitary fibrous tumor and you can see how these can easily be confused.  The best way to prevent these situations is to train your staff to watch for patients, especially children or teenagers, who are likely to be chewing gum or candy.

This case is from the paper 'What's in Your Mouth? The CT Appearance of Comestible Intraoral Foreign Bodies' by M. McDermott, B.F. Branstetter, E.J. Escott.

Lemonhead
Solitary Fibrous Tumor
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CBCT: What is it and how does it work?

Dr. Barett Andreasen, Oral and Maxillofacial Radiologist

The introduction of cone-beam computed tomography (CBCT) has heralded a shift from a 2D to a 3D approach in image acquisition and patient management. This technology has given dentistry unprecedented diagnostic information that has forever changed how we approach patient treatment. But what is CBCT and how does it work?

CBCT technology is a recent technology utilizing a divergent pyramidal- or cone-shaped x-ray beam directed through the area of interest onto an x-ray detector. The x-ray source and detector rotate about the area of interest, capturing multiple projection images in a single rotation of the gantry. (This diverges from conventional CT which uses a fan-shaped x-ray beam in a helical progression to capture individual slices of the area of interest, requiring multiple passes of the gantry.)

These acquired projection images are similar to traditional 2D lateral or posterior-anterior cephs, with each subsequent image being slightly offset from the previous one. The number of these images captured normally ranges from 100 to >600 and is dependent on the number of images acquired per second, the range of the trajectory arc, and the speed of the rotation. Once the projection images have been acquired, the data must be reconstructed to create the volumetric data, which is evaluated on your favorite CBCT viewer.

Advantages of CBCT include rapid scan times, reduced patient radiation dose, high resolution images, measurements free of distortion and magnification, 3D volume rendering and the ability to reorient the scan to realign the area of interest. CBCTs are limited by artifacts (either patient-related or scanner-related), image noise, and poor soft tissue contrast.

CBCT technology has had a tremendous impact on how dentistry is practiced and will only become more commonplace as time progresses.

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Radiation from Dental X-rays

Dr. Barett Andreasen, Oral and Maxillofacial Radiologist

During your time in practice, you will undoubtedly run into a patient who is concerned with exposure from radiographic examinations. Our goal as healthcare providers is to help alleviate their concerns and to present information in a way that is positive and easy to understand.

The easiest way I've found to convey this information is to compare the dose received by dental radiographic examination to radiation exposure to common activities. Here's a list of other radiation sources compared to dental examinations:

Non-dental and non-medical sources
Eating a banana: .1 µSv
Using a CRT monitor for a year: 1 µSv
Extra dose from spending a day in Denver: 1.5 µSv
Normal daily background dose for an average person: 10 µSv
Airplane flight from NY to Los Angeles: 40 µSv
Additional yearly dose to aircrew members: 3,000 µSv
Yearly cosmic radiation while living at sea level: 300 µSv
Yearly cosmic radiation while living in Denver: 800 µSv
Yearly dose from natural potassium in the body: 390 µSv
Yearly dose from naturally present Radon in average US home: 2,300 µSv
Total average yearly dose from natural background radiation: 3,000 µSv

Medical sources
Chest x-ray: 100 µSv
Mammogram: 400 µSv
Head CT: 2,000 µSv
Chest CT: 7,000 µSv

Dental sources
BW series: 5 µSv
FMX: 35-170 µSv
Panoramic: 10 µSv
CBCT: approx. 200 µSv (varies from approx. 11-1000 µSv as dose is dependent on field of view and scanning protocols)

So when I have an individual in the clinic who expresses concern about the amount of radiation they'll be receiving, I'll phrase my response similar to the statement below:

"I understand your concern about radiation from dental x-rays. Our x-ray machines are designed to administer as little radiation as possible while maintaining diagnostic accuracy. To give you an idea of how little radiation you would receive, you would be exposed to more radiation if you were to fly round trip from here in Los Angeles to NYC than from the x-rays (FMX) we're taking today. Or, if you were to move from Los Angeles to Denver, you'd be exposed to twice as much radiation in a year as you would from taking a CBCT today. Compared to the natural background radiation that we all receive, dental x-rays contribute a minimal amount of radiation but make a significant impact on the outcome of your treatment and overall health."

While I'm sure this information will not assuage every patient, acknowledging the patient's concern and helping them understand the principle behind radiation exposure hasn't failed me yet!

Sources come from the ADA, EPA, and NRC.

I've attached some images that compares doses from different radiation sources for reference. Just a note - be careful of units. 1,000 µSv = 1 mSv = 100 millirem.

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Arrested Pneumatization of the Sphenoid Sinus

Dr. Barett Andreasen, Oral and Maxillofacial Radiologist

Today I'd like to share an interesting case in a region that is frequently captured in dental CBCT scans. I've included images with labels of the surrounding anatomy as well as a skull with approximate locations of the slices to help you get oriented.

A patient presented with an incidental finding located at the left sphenoid sinus and greater wing of the sphenoid. The area of interest is delineated by white arrows in the images. The CT slices show a nonexpansile lesion with a thin cortical margin and curvilinear internal calcifications. Patient denied any symptoms.

While the appearance is very unusual, this finding represents arrested pneumatization of the sphenoid sinus, a normal anatomical variation caused by an interruption of the normal development of the sinuses. The development of the sphenoid sinus begins with fatty transformation and fat involution of the bone marrow, followed by aeration of the marrow that results in pneumatization of the bone. The normal pneumatization process occurs soon after birth and ends at 10-14 years of age. Interruption of this process results in an area of persistent atypical fatty marrow that persists into adulthood and manifests as a nonexpansile lesion with thin cortical margins and curvilinear internal calcifications. The lesion will also respect the margins of adjacent foramina and lacks a normal trabecular pattern found in the adjacent bone. While arrested pneumatization can technically occur in any sinus, there is a marked predominance for the sphenoid sinus; however, the reasons why such a predominance is present or the causes for the alteration in normal development are not fully understood.

Potential differential diagnoses include: intraosseous lipoma, intraosseous hemangioma, fibrous dysplasia, ossifying fibroma, chordoma, chondrosarcoma, and metastases. In contrast to arrested pneumatization, all these conditions usually show signs of mass effect on the surrounding structures.

As this is a normal anatomical variation, no treatment is necessary. However, MR imaging may be indicated to rule out osseous pathology.

This case came from the article "The CT Prevalence of Arrested Pneumatization of the sphenoid Sinus in Patients with Sickle Cell Disease" by A.V. Prabhu, and B.F. Branstetter.

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The Premier Dental Radiology Experience

Interpretation of Panoramic Radiographs

Dr. Barett Andreasen, Oral and Maxillofacial Radiologist

Evaluation of panoramic radiographs is difficult and often ineffective if a dentist does not understand the anatomical structures captured in the panoramic.  The superimposition of bony structures and soft tissue, in addition to ghost and double images created upon acquisition, make panoramic radiographs challenging to decipher.  Normal anatomy can easily be mistaken as pathology and pathology can also be missed when unfamiliar landmarks are not closely evaluated.

One thing that drastically improved my understanding of panoramic anatomy are these two figures.  Something about seeing the radiographic landmarks referenced on a skull just made everything click.  This increased understanding of anatomy has changed the way I approach panoramic evaluations and has been the deciding factor when detecting pathology in several cases where pathology would have otherwise been missed.

These images come from Interpretation of panoramic radiographs by Perschbacher and Oral Radiology Principles and Interpretation by Mallya and Lam.

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The Premier Dental Radiology Experience

Panoramic Evaluation

Dr. Barett Andreasen, Oral and Maxillofacial Radiologist

Panoramic radiographs are a key component of patient screening and treatment planning; however, these radiographs are only as good as your ability to recognize and detect abnormalities.  A methodical and systematic approach to panoramic evaluation is critical to ensure all significant findings are identified.

To test your own routine, print off a panoramic on a paper and trace the path your eyes take while evaluating the panoramic. Identify areas that you may unintentionally ignore and work those areas into your routine.  Using this method has allowed me to hone and refine my own approach to panoramic evaluations, ensuring that I am able to detect all significant findings. You'll also find that as you develop your routine that it is significantly faster and efficient than a haphazard search through the x-ray.

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