Oral and maxillofacial imaging is no exception. As a specialty that deals with uncommon lesions and complex anatomy, both students and practicing dental clinicians may benefit from this simplistic, pattern-based approach. This presentation describes a compendium of the classic signs in oral and maxillofacial radiology.

1. CLASSIC SIGNS IN ORAL
AND MAXILLOFACIAL
RADIOLOGY
Presented by
Dr. Rahul Srivastava
Professor
Rama Dental College Hospital
& Research Centre, Kanpur

2. “Soap bubble and honeycomb” appearances
Soap bubble is reserved for lesions consisting of
several circular compartments that vary in size and
usually appear to overlap somewhat.
Honeycomb applies to lesions whose compartments
are small and tend to be uniform in size.

3. “Soap bubble and honeycomb” appearances
The internal structure of solid/multicystic
ameloblastoma is typically mixed, with the
presence of bony septa creating multiple internal
compartments, or loculations. This pattern reflects
the presence of cystic formations within the tumor.

4. These cystic regions remodel the trapped bone into
curved shapes, providing a “soap bubble” pattern
(large radiolucent compartments of variable size) or
a “honeycomb” pattern (numerous small
compartments).
Generally, the compartments are large in the
posterior mandible and small in the anterior
mandible.

5. Soap bubble pattern may also be observed in
odontogenic keratocysts and giant cell granulomas .
Cropped Panoramic view of
the lesion shows numerous
small compartments
(“honeycomb” pattern)
Cropped Panoramic image shows,
multilocular “soap bubble”
lesions

6. Sun ray / sunburst appearance
If the lesion grows rapidly but steadily, the
periosteum will not have enough time to lay down
thin shell of bone, and in such cases, the tiny fibers
that connect the periosteum to the bone (Sharpey’s
fibers) become stretched out perpendicular to the
bone.
When these fibers ossify, they produce a pattern
sometimes called “sunburst” periosteal reaction.

7. Lesions exhibit bone production with a “sunray”
appearance:
 Chondrosarcomas.
 Fibrosarcomas
 Metastatic breast and prostate tumors.
 Osteosarcoma.
 Hemangioma.
 Osteoblastoma.

8. Osteosarcoma of the mandible. Cross-
sectional cone-beam computed tomography
(CBCT) image shows an exuberant
periosteal reaction with a “sunburst”
pattern

9. “Spiked root” appearance
Benign tumors tend to resorb adjacent root surfaces
in a smooth fashion. When root resorption is
associated with malignant disease; however, the
resorption often occurs in smaller quantities,
causing thinning of the root into a “spiked” shape”.

10. In the absence of generalized periodontitis,
widening of the periodontal ligament space that
involves one or several adjacent teeth
(characteristically limited to one side of the root)
could be an early sign of malignancy (Garrington’s
sign)

11. Increased bone density and irregular widening of the
periodontal ligament spaces of the teeth of the left
mandibular body (Garrington’s sign). Also, note the
“spiking” resorption of the mesial root of the first
molar

12. “Sharpened pencil” appearance
Rheumatoid arthritis is characterized by synovial
proliferation (pannus) and secondary erosive
changes in the bone.
Images of the TMJ often show progressive erosion at
the attachment of the synovial lining of the anterior
and posterior condylar surfaces, resulting in a
small, pointed condyle in a large fossa (“sharpened
pencil” appearance).

13. Coronal CBCT image of the TMJ shows small remnants of
the condylar heads after severe erosion, resulting in a
“sharpened pencil” appearance of the condyle.

14. “Tram-track” appearance
Monckeberg’s medial vascular calcification
(arteriosclerosis) is characterized by degeneration
and subsequent deposition of calcium in the medial
coating of the artery.
These deposits, however, do not narrow the vessel
lumen or interfere with blood flow.

15. This type of calcification is most frequently seen in
patients with diabetes mellitus or chronic renal
failure.
Radiographically, the calcified vessel appears as a
parallel pair of thin, radiopaque lines that outline
the affected vessel.
It is described as having a “tramtrack” or “pipe
stem” appearance

16. Sagittal CBCT image shows “tram-track”
calcification of the facial artery (arrow)

17. “Sausage-string” appearance
Sialodochitis results in dilation of the involved duct
secondary to distal obstruction. If interstitial
fibrosis develops, however, it is seen on sialography
as a “sausage-string” in the main and secondary
ducts that is produced by intermittent strictures
and dilations.

18. “Hanging drop” appearance
The blowout orbital wall fracture results from a
direct blow to the orbit. The force of the blow is
transmitted to the orbital walls, among which the
floor is most susceptible.

19. The classic “hanging drop” appearance of the
herniated orbital content is clearly seen on a
radiographic Waters’ view or on a coronal
computed tomographic (CT) image, as is the
“trapdoor” appearance of the displaced orbital
floor.

20. Waters view shows the “hanging drop” sign of
the orbital floor blowout fracture with
herniation of soft tissue into the maxillary sinus
(arrow). An air–fluid level is visible in the
maxillary sinus (arrowhead)

21. “Punched-out” appearance
A “punched-out” border is one that has a sharp
boundary with no peripheral bone reaction. Its
appearance is similar to that of a hole in a
radiograph created with a paper punch.
The border of the resulting hole is well-defined, and
the surrounding bone has a normal appearance up
to the edge of the hole.

22. “Punched-out” lesions are typically indicative of:
 Multiple myeloma.
 Langerhans cell histiocytosis.
Punched out
radiolucency

23. “Ground-glass” appearance
The radiological features of fibrous dysplasia vary
considerably depending on the maturity of the
lesion.
In the early stage, fibrous dysplasia appears as a
unilocular or multilocular radiolucency with ill-
defined or welldefined borders.

24. In the middle stage, radiopaque tissue appears in
the radiolucent structure.
In the mature stage, the internal structure has a
granular, radiopaque pattern often appearing as
“ground-glass” opacities (resembling glass that has
been ground or etched to create a roughened,
nontransparent surface) with ill-defined borders
blending into normal adjacent bone.

25. Evident in cases of fibrous dysplasia, paget’s
disease, hyperpararthyroidism and ossifying
fibroma.
Ground glass appearance in the case of
ossifying fibroma on maxillary
tuberosity region

26. “Cotton-wool” appearance
The late stage of Paget’s disease of bone classically
presents with rounded, dense, radiopaque patches
of abnormal bone, creating a “cotton-wool”
appearance.
Florid cementoosseous dysplasia may also present
with “cotton-wool”-type radiopaque regions

27. “Cotton-wool” appearance

28. “Moth-eaten” appearance
The first radiographic evidence of osteomyelitis is
often a slight decrease in the density of the
involved bone, with a loss of sharpness of the
trabecular structure.
The bone resorption becomes more profound with
time, resulting in ill-defined lytic areas throughout
the affected bone.

29. This pattern sometimes takes the form of “moth-
eaten” bone (similar to a piece of clothing ruined by
moth larvae).
Also noticed in early stages of osteosarcoma,
squamous cell carcinoma,osteoradionecrosis,
leukemia, malignant lymphoma.

30. Typical “moth-eaten” pattern of bone destruction,
areas of rarefaction, sequestrum formation and a
periosteal reaction at the inferior border of the
mandible (arrow)

31. “Floating teeth” appearance
It is a result of alveolar bone destruction around
the root of the teeth giving the appearance of a
floating tooth .
Floating teeth
appearance

32. Lesions have more relationship with floating teeth
appearance: Aggressive periodontitis, Langerhans
histiocytosis, Burkitt’s lymphoma, multiple
myeloma, Metastatic tumors, Primary intraosseous
carcinoma (intraosseous squamous cell carcinoma),
Ewing’s sarcoma, Hyperparathyroidism, and
Cherubism.

33. “Bull’s-eye” appearance
When the roots are dilacerated facially or
lingually, the central X-ray beam passes parallel to
the long axis of the dilacerated portion of the root.
This pattern, in turn, leads to a round, radiopaque
area with a central dark spot (caused by the apical
foramen of the root canal), giving the appearance
of a “bull’s eye”.

34. The root tip of the first premolar root is dilacerated in
the buccolingual direction so tits long axis lies along
the path of the X-ray beam. “Bull’s eye” appearance
produced by the root canal, root tip, and periodontal
ligamental space.

35. “Onion-skin” appearance
Onion skin appearance is due to lamellated
periosteal reaction where multiple concentric
layers of new bone are laid down.
Radiographically, sialoliths usually have a smooth
shape. Their internal structure is most often
homogeneously radiopaque with evidence of a
laminated pattern, giving sialoliths an “onion-skin”

36. This pattern is most commonly seen in
inflammatory lesions (e.g., chronic osteomyelitis
with proliferative periostitis) and rarely in tumors
such as Ewing sarcoma and Langerhans cell
histiocytosis.

37. Mandibular occlusal image shows a
calcified sialolith in Wharton’s duct.
Note the position and the hint at a
laminated “onionskin” internal
pattern.
Mandibular occlusal image shows
laminated “onionskin” pattern in case of
proliferative periostitis of Garre.

38. “Cookie-bite” appearance
The term “cookie-bite” lesion was first used in the
medical literature by Deutsch et al. to describe a
saucerized, osteolytic, cortical, metastatic lesion
derived from bronchogenic carcinoma.
The “cookie-bite” appearance has also been
observed in conjunction with osteomyelitis of the
jaw

39. Panoramic image shows a “cookie-bite” pattern of bone destruction
in the right mandible, a wide zone of transition with permeative
changes within it, and lack of sclerosis at the margin.

40. “Spoke-wheel” appearance
Central (intraosseous) hemangioma usually appears
as a multilocular, expansile lesion that may be
associated with displacement and resorption of
adjacent teeth.
When forming the basic multilocular pattern,
however, the trabeculae may be arranged as a hub
or in a spoke-of-a-wheel or honeycomb pattern.

41. Hemangioma of the right mandible. Panoramic radiograph shows
the lesion with coarse trabeculae radiating from a common center
in a manner roughly resembling the spokes of a wheel. Dark spaces
between trabeculae are blood cavities

42. “Doughnut” appearance
Osteoma cutis is a rare soft tissue calcification in
the skin.
It is usually associated with chronic acne scars.
Radiographically, osteoma cutis most commonly
appears in the cheek as multiple, “doughnut”, or
“washer-shaped”, radiopacities with radiolucent
centers representing central marrow cavities

43. Osteoma cutis. Bitewing image shows faint
doughnut-shaped radiopacities in the cheek

44. “Beaten copper” appearance
The “beaten copper” appearance refers to
prominent cranial markings seen on skull
radiographs.
These markings are thought to correspond to the
gyral pattern of the growing brain and are
generally considered a normal finding in children.

45. A diffuse “beaten copper” appearance, however,
has been shown to be related to elevated
intracranial pressure from the growing brain in
patients with premature craniosynostosis.
These markings may appear as multiple
radiolucent areas that resemble hammered copper

46. Lateral cephalogram showing copper
beaten appearance on skull.

47. “Bird’s beak” appearance
Degenerative joint disease, also known as
osteoarthritis and osteoarthrosis, is a non-
inflammatory disease characterized by the
breakdown of the articular cartilage leading to
eventual degeneration of the underlying bone.

48. Degenerative changes of the joint include flattening
and irregularities of the articular surfaces,
osteophytosis (projections of bone formation at the
periphery of the articulating surfaces) and
subchondral degeneration.
Flattening and osteophyte formation results in
“beaking” at the anterior aspect of the condyle.

49. Panoramic radiograph shows bilateral flattening osteophyte
formation at the anterior aspect of the condyles giving a
“bird’s beak” appearance

50. Codman’s triangle
A triangular area of new subperiosteal bone which
is formed when a tumour raises the periosteum
away from the bone.
A Codman triangle is found as a pseudo triangle on
radiograph of normal bone.

51. A two-sided appearance of the triangle is due to a
tumour which is growing at a faster rate than the
normal growth of the periosteum hence tearing of
periosteum occurs which in turn provides
ossification on the second edge of the triangle.
Codman’s triangle is evident in alveolar bone
carcinoma, osteogenic sarcoma, Ewing’s sarcoma,
etc.

52. Codman’s triangle

53. Hair on end appearance
It is due to the periosteal reaction which appears
as a perpendicular trabeculations along the skull
vault by marrow hyperplasia.
According to the degree of hyperplasia the bone
changes.
Evident in sickle cell anemia and thalassemia

54. Hair on end appearance

55. Snow Driven appearance
Radiologically, CEOT is characterized by unilocular
or multilocular radiolucency that often exhibits
mixed radiographic feature (65%) due to the
presence of scattered flecks of calcifications, often
produce a typical “snow driven’’ appearance.

56. Presence of a radiopaque mass in the center of the lesion
(black arrow) with radiopaque streaks has the appearance of
“driven snow”.

57. Balloon like or peripheral egg shell appearance
Radiopacity is most commonly seen on the
periphery of the expanded cortex than inside of
the expanded border.
Xray beam is more attenuated in the cortical bone
which is not thicker on the cortex than rest of the
area because of the longer path length of photons
through the bony cortex on the periphery.

58. In radiograph, these circular, fluid-filled shaped
structure gives a balloon like appearance.
This type of balloon like appearance is most
commonly seen in follicular cysts.
Balloon like appearance

59. Downward bowing
This radiographic pattern is due to the lesion that
invade to the inferior border of the mandible when
their size reaches a limit.
It appears as a round tumour mass due to the
centrifugal growth pattern and thus equal
expansion can be observed in all directions.

60. Downward bowing appearance is commonly seen in
cemento-ossifying fibroma and ameloblastoma
Downward bowing in a patient
with ameloblastoma

61. Ghost teeth
Teeth in a region or quadrant of maxilla or
mandible are affected to the extent that they
exhibit short roots, wide open apical foramen and
large pulp chamber, the thinness and poor
mineralisation qualities of the enamel and dentine
layers have given rise to a faint radiolucent image,
hence the term "Ghost teeth".

62. Ghost teeth is seen in case of regional
odontodysplasia
Ghost teeth appearance

63. Heart shaped radiolucency
Anterior nasal spine overlaps cystic radiolucency
in the maxillary central incisor region thus giving
a heart shaped radiographic pattern.
It is a characteristic sign for nasopalatine cyst.

64. Heart shaped radioucency

65. Mottled appearance
Due to uneven spots it is named as mottled
appearance.
Radiographically it appears as a mixed lesion with
patchy radiolucency and radiopacities are found
interspersing between lucent areas.
Evident in fibrous dysplasia, ossifying fibroma,
Paget’s disease, etc.

66. Mottled appearance

67. Step ladder appearance
The step ladder appearance occurs due to the
horizontal trabeculations of medullary bone of
jaws.
Most commonly observed in sickle cell anemia and
also in normal mandibular alveolar bone.

68. Step ladder appearance

69. Tennis racket appearance
It is a radiographic appearance present in
radiolucent multilocular lesions comprising of
angular compartments which results from the
development of straight septa.
Tennis racket appearance is the characteristic sign
of odontogenic myxoma.

70. Tennis racket appearance

71. Pear-shaped or tear shaped appearance
Radiographic picture is of globulomaxillary cyst is
inverted pear-shaped or tear shaped, with well
defined radiolucency between the separated roots
of lateral incisor and canine.

72. Pear-shaped or tear shaped appearance

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