Step I

Describe the variable radiopacity noting in particular:

Step II

Decide whether the variable radiopacity is:

Step III

If the radiopacity is pathological, decide within which of the following major categories it should be placed:

Step IV

Consider the subdivisions of these pathological categories. A typical list is shown in Table 28.1.

Table 28.1 Classification of the more common lesions that can present as variable radiopacities in the jaws

Step V

Compare the radiological features of the unknown opacity with the typical radiological features of these possible conditions. Then construct a list showing, in order of likelihood, all the conditions that the lesion might be. As mentioned in Chapter 27, this list forms the radiological differential diagnosis.

The typical radiographic features of the important radiopacities are described below using a similar style to that adopted in Chapter 27. It must be emphasized that this is a simplified approach and that most lesions can produce a variety of appearances.

Compound odontome

This odontome is made up of several small tooth-like denticles. The miniature tooth shapes are of dental tissue radiodensity, with a surrounding radiolucent line, and are easily identified radio-graphically (Fig. 28.3).

Fig. 28.3 Periapical of the region showing a radiopaque compound odontome (arrowed), consisting of small denticles.

Complex odontome

This odontome is made up of an irregular, confused mass of dental tissues bearing no resemblance in shape to a tooth. The enamel content provides the dense radiopacity, suggestive of dental tissue and again the mass is surrounded by a radiolucent line (Fig. 28.4).

Fig. 28.4 Right side of a panoramic radiograph showing the typical irregular, densely radiopaque mass of a complex odontome in the position of (arrowed). It is preventing the eruption of . The opacity shows the characteristic surrounding radiolucent line, confirming its dental tissue origin.

Exostoses, including tori (mandibular or palatal)

Exostoses are small, irregular overgrowths of bone sometimes developing on the surface of the alveolar bone. They consist primarily of compact bone and produce an ill-defined radiopacity when superimposed over the bulk of the alveolar bone. Usually two views are required to establish the exact site (see Fig. 28.7).

Fig. 28.7 A Periapical of showing ill-defined areas of radiopacity (arrowed) overlying the teeth. B Lower 90° occlusal of the same patient showing the large irregular exostoses (mandibular tori) on the lingual aspect of the mandible (arrowed).

Specific exostoses develop in particular sites and are often bilateral:

Calcifying epithelial odontogenic tumour (CEOT or Pindborg tumour) (Fig. 28.8)

Defined by the WHO as a locally invasive epithelial odontogenic neoplasm, characterized histologically by amyloid material that may become calcified.

Fig. 28.8 A Right side of a panoramic radiograph showing a calcifying epithelial odontogenic tumour in the maxilla (arrowed) associated with the unerupted . There are obvious areas of calcification within the lesion. B Part of a panoramic radiograph showing another CEOT (arrowed) associated with the unerupted lower left canine, with only faint internal calcification. C Right side of a panoramic radiograph showing a poorly defined calcifying epithelial odontogenic tumour (arrowed) associated with the unerupted molar. D Lower 90° occlusal of the same patient showing the expansive, multilocular nature of the lesion and the discrete internal calcifications.

• Age: 20–60 year-old adults.

• Frequency: Rare — approximately 1% of all odontogenic tumours.

• Site: —Molar/premolar region of the mandible.

— Maxilla occasionally.

• Shape: — Unilocular or multilocular

— Usually round

— Often associated with an unerupted tooth, particularly .

• Outline: — Variable definition, frequently scalloped

— Variable cortication.

• Radiodensity: — Radiolucent in early stages then numerous scattered radiopacities usually become evident within the lesion often most prominent around the crown of any associated unerupted tooth

— This appearance is sometimes described as driven snow.

• Effects: — Adjacent teeth sometimes displaced, sometimes resorbed

— Expansion of the cortical bone.

Ameloblastic fibro-odontoma (Fig. 28.9)

These rare, unilocular or multilocular odontogenic tumours resemble closely ameloblastic fibromas (see Fig. 25.10), and also affect children. However, they are often associated with an unempted tooth and usually contain enamel or dentine, either as multiple, small opacities or as a solid mass.

Fig. 28.9 Oblique lateral showing a large expansive ameloblastic fibro-odontoma (arrowed) in the mandible of a 5-year-old. The internal calcification is comparable to tooth tissue and histopathology confirmed the presence of enamel and dentine. Note the unerupted tooth.

Adenomatoid odontogenic tumour (AOT) (Fig. 28.10)

Described by the WHO as being composed of odontogenic epithelium embedded in a mature connective tissue stroma and characterized by slow but progressive growth.

Fig. 28.10 A Part of a panoramic radiograph showing a monolocular adenomatoid odontogenic tumour in the anterior maxilla (arrowed) surrounding the unerupted . Internal calcification is evident. B Periapical of the anterior maxilla showing another adenomatoid odontogenic tumour (arrowed) with internal calcification, associated with an unerupted canine.

(Reproduced from A Radiological Atlas of Diseases of the Teeth and Jaws with kind permission from the authors R.M. Browne, H.D. Edmondson and P.G.J. Rout.)

Calcifying cystic odontogenic tumour (calcifying odontogenic cyst or Gorlin’s cyst) (Fig. 28.11)

As stated earlier, the new name of this lesion reflects its classification by the WHO as an odontogenic tumour, who described it as a benign cystic neoplasm of odontogenic origin characterized histologically by ameloblastoma-like epithelium with ghost cells that may calcify. It presents typically anteriorly in either the mandible or the maxilla as a unilocular, well-defined, well-corticated radiolucency resembling other odontogenic cysts, but, as it develops, a variable amount of calcified material becomes evident, scattered throughout the radiolucency. The opacities can range from small flecks to large masses.

Fig. 28.11 A Periapical showing a well-defined calcifying cystic odontogenic tumour (arrowed) in the mandible with obvious areas of internal calcification. B Periapical showing a calcifying cystic odontogenic tumour (arrowed) in the anterior maxilla. The central incisor is unerupted and there is internal calcification of tooth-like density.

Cementoblastoma (Fig. 28.12)

As indicated in Table 27.1, the cementoblastoma is classified by the WHO as an odontogenic tumour which is characterized by the formation of cementum-like tissue in connection with the root of a tooth.

Fig. 28.12 A Periapical showing the typical radiopaque mass at the apex of the of a cementoblastoma, the so-called golf ball appearance. The mass is attached to the root and has a thin radiolucent line around it (arrowed). B Part of a panoramic radiograph showing a radiopaque cementoblastoma at the apex of (arrowed).

Osteomas (Fig. 28.13)

Osteomas of the jaws may be located in the medullary bone (endosteal osteoma) or arise on the surface of the bone as a pedunculated mass (periosteal osteoma). They are usually detected in young adults and are typically asymptomatic, solitary lesions. Multiple jaw osteomas are a feature of the rare inherited condition Gardner’s syndrome.

Fig. 28.13 A Oblique lateral of right ramus of the mandible showing a round radiopaque compact osteoma (arrowed). B Part of a PA jaws of the same patient showing the lesion (arrowed) arising from the lateral surface of the mandible confirming a periosteal osteoma. C Periapical showing a periosteal cancellous osteoma (arrowed). D Part of a panoramic radiograph and E PA jaws of the same patient showing a very large endosteal compact osteoma (arrowed) in the body of the mandible.

There are two main types:

Both tumours are uncommon. The type of bone making up the tumour determines the degree of radiopacity.

Osteosarcoma (Fig. 28.14)

Rare, rapidly destructive malignant tumour of bone. From a radiological viewpoint, there are three main types:

Fig. 28.14 A Right side of a PA jaws of a 7-year-old showing an osteosarcoma in the ascending ramus of the mandible. The sunray or sunburst appearance is evident medially and laterally (arrowed). B Oblique lateral showing a very extensive osteogenic osteosarcoma of the mandible with obvious sunray or sunburst bone formation. C Left side of a panoramic radiograph showing an irregular, poorly defined area of radiopacity (arrowed) in the body of the mandible. D Lower 90° occlusal of the same patient showing extensive buccal and lingual abnormal bone formation (arrowed) of another osteogenic osteosarcoma.

Early features:

Later features:

Periapical osseous dysplasia (Fig. 28.15)

Fig. 28.15 Periapical showing the latter stage of periapical osseous dysplasia. The developing internal calcification is arrowed.

Focal osseous dysplasia (Fig. 28.16)

This usually solitary fibrocemento-osseous lesion occupies a portion of the spectrum between the periapical and florid cemento-osseous dysplasias.

Fig. 28.16 Oblique lateral showing relatively late-stage focal osseous dysplasia in the region of the extraction site (arrowed). An appreciable amount of internal calcification is evident.

Florid osseous dysplasia (Fig. 28.17)

Fig. 28.17 Panoramic radiograph showing the multiple lesions (arrowed) of variable radiodensity of florid osseous dysplasia.

Familial gigantiform cementoma

This is a rare familial osseous dysplasia. It is inherited as an autosomal dominant condition and confined almost exclusively to young, 10–20 year-old whites. The lesions characteristically show relatively rapid growth, causing marked facial deformity.

Fibrous dysplasia (Fig. 28.18)

Fibrous dysplasia is described by the WHO as a genetically-based sporadic disease of bone affecting single or multiple bones. The jaws and other bones in the skull can be affected as well as other bones in the skeleton. The general radiological features of fibrous dysplasia are covered in Chapter 32.

Fig. 28.18 Periapical of the upper right maxilla showing the generalized radiolucency with the fine internal trabeculation of monostostic fibrous dysplasia, giving a ground glass appearance. The almost imperceptible junction between abnormal and normal bone is arrowed.

The radiographic features of jaw lesions include:

Ossifying fibroma (Fig. 28.19)

This lesion has previously been called cementifing fibroma and cemento-ossifying fibroma but the 2005 WHO classification uses the term ossifying fibroma which is described as a well-demarcated lesion composed histologically of fibrocellular tissue and mineralizing material of varying appearance.

Fig. 28.19 A Part of a panoramic radiograph of a 9-year-old showing an intermediate stage ossifying fibroma, with fine internal calcifications evident, in the right body of the mandible (arrowed). There is also displacement of the unerupted lower premolars and permanent canine. B Part of panoramic radiograph showing a large ossifying fibroma (arrowed) occupying most of the body of the mandible with considerable internal calcification. C Right side of a panoramic radiograph showing a large mature radiopaque ossifying fibroma (arrowed).

Radiopaque salivary calculi (see Ch. 33)

Submandibular gland calculi (Fig. 28.20) are often radiopaque and develop within the main duct or in the gland itself. Those in the main duct can be superimposed on the alveolar bone producing an opacity apparently within the bone. Stones in the gland present usually below the lower border of the mandible.

Fig. 28.20 A Right side of a panoramic radiograph showing a large radiopacity in the lower premolar region (arrowed). B Lower 90° occlusal of the same patient showing the opacity to be a large stone in the right submandibular duct.

Calcified lymph nodes (Fig. 28.21)

Calcification of lymphoid tissue is relatively common following chronic infection (e.g. tuberculosis), especially in older patients.

Fig. 28.21 Panoramic radiograph showing two calcified lymph nodes in the left cervical chain (solid arrows). Note also the ghost shadows of the lymph nodes on the right premolar/canine region (open arrows).

Calcified tonsils (Fig. 28.22)

Calcification of the tonsillar lymphoid tissue is sometimes seen as an incidental finding on dental panoramic radiographs, especially in elderly patients. Areas of calcification appear as small irregular opaque masses overlying the superior aspect of the ramus of the mandible; they are often bilateral.

Fig. 28.22 Left side of a panoramic radiograph showing the typical appearance of tonsillar calcifications (arrowed) overlying the ramus of the mandible.

Phleboliths (Fig. 28.23)

Phleboliths are calcifications of thrombi within veins and are occasionally seen in haemangiomas. If the radiograph shows the calcified blood vessel end-on, the phlebolith has a characteristic target appearance — radiopaque around the periphery and radiolucent in the centre.

Fig. 28.23 Oblique lateral showing multiple phleboliths (arrowed) associated with a haemangioma. Note the typical target appearance of some of the calcifications.

Calcified acne scars

Occasionally calcification can develop in the scars of severe acne producing multiple small radiopacities in the area involved. If acne calcification is suspected radiographically, the diagnosis can be confirmed by clinical examination.