This document discusses various pathologies that can affect the mandible and maxilla. It begins by discussing cystic masses such as odontogenic cysts (e.g. periapical, residual, dentigerous cysts), non-odontogenic cysts (e.g. solitary bone cyst, aneurysmal bone cyst), and lesions associated with conditions like hyperparathyroidism. It then covers benign tumors including ameloblastoma and odontoma. Radiographic and CT features are provided for each condition along with examples of imaging findings. Differential diagnoses and key distinguishing features are also reviewed.

1. Head & Neck
Mandible & Maxilla

2. Mohamed Zaitoun
Assistant Lecturer-Diagnostic Radiology
Department , Zagazig University Hospitals
Egypt
FINR (Fellowship of Interventional
Neuroradiology)-Switzerland
zaitoun82@gmail.com

5. Knowing as much as
possible about your enemy
precedes successful battle
and learning about the
disease process precedes
successful management

6. Mandible & Maxilla
a) Cystic Masses
b) Benign Tumors
c) Malignant Tumors
d) Mandibular Osteomyelitis
e) TMJ

7. a) Cystic Masses :
(I) Odontogenic (Dental) cysts :
1-Periapical Cyst
2-Residual Cyst
3-Dentigerous Cyst
4-Odontogenic Keratocyst
(II) Non-Odontogenic Cysts :
1-Solitary Bone Cyst
2-Aneurysmal Bone Cyst
3-Hyperparathyroidism (Brown Tumor)
4-Ameloblastoma
5-Eosiniphilic Granuloma
6-Giant Cell Granuloma
7-Fibrous Dysplasia

8. (I) Odontogenic (Dental) cysts :
1-Periapical Cyst
2-Residual Cyst
3-Dentigerous Cyst
4-Odontogenic Keratocyst

9. 1-Periapical Cyst : (Radicular Cyst)
-The most common odontogenic cyst
-Caused by caries and infection
-Periapical lucency with sclerotic margins at
tooth apex
-Can become periapical abscess
-Usually asymptomatic
-No malignant potential

10. Radicular cyst in a 40-year-old man, an abnormality was seen incidentally on a
panoramic radiograph obtained for planning of denture treatment, panoramic
radiograph shows a retained tooth fragment with an absent lamina dura, extending
from the root apex is an ellipsoid, corticated, lucent lesion with no internal calcification
(arrows), an appearance consistent with a root fragment and associated radicular cyst

11. Periapical cyst in a 60-year-old woman, CT (a) and coronal reformatted
CT (b) demonstrate a radiolucent lesion (arrows) surrounding the
apex of a molar, a defect with dental filling (arrowhead) is present
within the crown of the toot

12. Periapical cyst in a 40-year-old man, Panorex image demonstrates a
circular radiolucent lesion (arrow) at the apex of a molar, note the
dental filling (arrowhead) from a prior procedure

13. Radicular cyst. a Panorama x-ray shows a unilocular radiolucent lesion
with well-defined borders (asterisk) displacing teeth 33 and 34,
b CT, sagittal oblique 2D MPR with bone windows shows cystic
lesion surrounding the root (dashed arrow) of the non-vital tooth 34.
Associated large caries with pulpal necrosis (arrow)

16. Periapical abscess with extraosseous extension in a 44-year-old man with left-
sided jaw pain and fever, (a) Axial CT image demonstrates a periapical
lucency (arrow) involving the root of the left mandibular third molar. Note the
associated cortical dehiscence (arrowhead), (b) Coronal CT+C
demonstrates a peripherally enhancing extraosseous abscess (arrowheads)
around the mandible

17. Periapical abscess, focal lucency at the apex of medial
upper incisor with surrounding bone destruction

18. 2-Residual Cyst :
-Residual cysts are periapical cysts retained
in the jaw after surgical removal of a non-
vital tooth
-Residual cysts are common and have
similar clinical and radiological features as
radicular cysts, however, there is always a
missing tooth

19. Residual cyst, Panorama x-ray shows unilocular well-defined lesion
with sclerotic borders (arrow) and missing tooth 36 above

20. 3-Dentigerous Cyst : (Follicular Cyst)
-The second most common odontogenic
mandibular cysts and the most common
developmental cysts of odontogenic origin
-Adjacent to crown of unerupted tooth
(typically the lower third molar)
-Unilocular, well-defined radiolucent lesion
with sclerotic borders around an
unerupted tooth crown

21. Follicular cyst in a 40-year-old man, Coronal reformatted CT image
reveals a cystic lesion with an unerupted tooth in the right molar
region (arrow), the crown of the tooth is contained within the lesion,
note the presence of bone remodeling rather than expansion

22. Dentigerous cyst in a 42-year-old man with painful third molars, (a) Panoramic
radiograph shows an ellipsoid, expansile, well-defined, corticated, lucent
lesion with undulating margins in the right mandible, an associated tooth is
seen within the lesion, (b) PA radiograph shows lingual expansion (arrow)

23. Dentigerous cyst. a OPT, b axial CT with bone windows
and c dentascan reconstruction show unilocular well-defined
radiolucent lesion (thick arrows) surrounding an unerupted tooth,
immediate vicinity of the mandibular canal (dashed arrow) to the
impacted tooth

27. 24-year-old man with dentigerous cyst, axial (A), coronal (B), and
volume-rendering 3D (C) CT images show well-circumscribed
unilocular radiolucent lesion (arrows) containing crown of unerupted
second molar

28. 4-Odontogenic Keratocyst : (OKC)
-Aggressive cystic jaw lesion in mandible (70%) or maxilla
(30%)
-Multiple OKC in a young patient should raise the possibility
of basal cell nevus syndrome (Gorlin-Goltz syndrome),
associated findings with this autosomal dominant
disorder include midface hypoplasia, frontal bossing and
prognathism, mental retardation, and calcification of the
falx cerebri
-It appears as a unilocular or multiloculated, elongated,
irregularly shaped radiolucency with a scalloped, well-
defined margin
-It lacks the more ballooning characteristics of other
odontogenic cysts (which is an important diagnostic
feature)
-CT : It shows higher attenuation values of its cyst fluid
than other jaw cysts (due to its high protein or keratin
content)

29. Odontogenic keratocyst in a 13-year-old boy, (a) Lateral oblique radiograph shows an
ellipsoid, expansile, multilocular, corticated, lucent lesion occupying the anterior two-
thirds of the left ramus with an impacted third molar crown displaced inferiorly within
the lesion, the mandibular canal appears to be displaced inferiorly as well, (b) PA
radiograph shows buccal (lateral) displacement of the third molar by the lesion

30. OKCs in a 22-year-old man, Panoramic reformatted CT image
demonstrates cystic lesions with well-demarcated borders (arrows)
within the mandible, there is no evidence of adjacent tooth root
erosion, note the slight expansile change and remodeling of the
mandibular cortex without bone destruction

31. 24-year-old woman with OKC, A, Oblique sagittal reconstructed CT image
obtained using bone algorithm shows large radiolucent lesion (arrows) in
posterior body of mandibular ramus, with scalloping of cortex, B, Axial
CT+C obtained using soft-tissue algorithm shows cystic lesion with mild
peripheral enhancement (arrow) breaking through cortex and extending into
left masseter muscle

32. Histologically proven KCOT, a OPT, axial CT image with bone window
(b) and soft tissue window (c) show multilocular well-defined
radiolucent lesion (asterisk) with thin, sclerotic borders, cortical
scalloping (arrow) and resorption of teeth roots. Cyst contents with
attenuation values of 40–50 HU mimicking solid tissue

34. *N.B. :
Gorlin Syndrome (Basal cell nevus) :
-This syndrome, a phakomatosis, consists of multiple basal
cell nevi of the skin, odontogenic jaw cysts (derived from
odontogenic epithelium) and a variety of other
abnormalities
-Skin : Multiple nevoid basal cell carcinoma
-Oral : Multiple jaw cysts (odontogenic keratocysts)
-Others :
*CNS : Agenesis of CC, congenital hydrocephalus,
medulloblastoma, meningioma
*Eyes : congenital blindness, cataracts, glaucoma &
coloboma
*Genital : uterine and ovarian fibromas (often with
calcification), hypogonadism, cryptorchism

35. OKC in a 41-year-old man with basal cell nevus syndrome (Gorlin-Goltz
syndrome), CT+C shows multiple cysts (arrows) in the mandible, cystic
lesions (arrowheads) are also identified within the maxilla, CT also
demonstrated a calcified falx and large frontal sinuses, findings that helped
establish the diagnosis

36. Basal cell nevus syndrome, OPG shows ultiple mandibular and
maxillary KCOTs (asterisks) associated with impacted teeth

37. Gardner syndrome in an 80-year-old man, Panorex radiograph
demonstrates multiple osteomas (arrows) throughout the mandible,
note the osteoma within the right maxilla (arrowhead)

38. (II) Non-Odontogenic Cysts :
1-Solitary Bone Cyst
2-Aneurysmal Bone Cyst
3-Hyperparathyroidism (Brown Tumor)
4-Ameloblastoma
5-Eosinophilic Granuloma
6-Giant Cell Granuloma
7-Fibrous Dysplasia

39. 1-Solitary Bone Cyst :
-This occurs during the 1st two decades of
life (mainly in the premolar or molar
regions of the mandible)
-It has a less well-defined margin than that
of an odontogenic cyst

42. Solitary (hemorrhagic) bone cyst in a 25-year-old woman, Coronal
reformatted CT image demonstrates a cystic lesion (arrows) within
the mandibular body, the mandibular cortex is thinned, note the
normal tooth (arrowhead) within the lesion, a finding that helps
distinguish the cyst from radicular or other odontogenic cysts

43. 56-year-old man with simple bone cyst, axial (A) and coronal (B) CT
images show well-circumscribed radiolucent lesion (arrows) with
cortical scalloping in anterior body of mandible without root
resorption, prominent expansile change is not typical of simple bone
cyst

44. 2-Aneurysmal Bone Cyst :
-It is typically found within the posterior
mandible and appears as a well-defined,
multilocular often septated, circular
radiolucency, there is often marked
cortical expansion
-CT : Multiple fluid levels can be seen

45. Large aneurysmal bone cyst showing expansion or
ballooning effect in posterior mandible

46. ABC, (a) Panoramic radiography showing a unilocular radiolucency, (b)
axial CT image of the mandible showing cortical expansion and
thinning

47. 3-Hyperparathyroidism (Brown Tumor) :
-Central giant cell lesions that occur in patients with long-
standing hyperparathyroidism
-These lesions can arise in any bone, including those of the
facial skeleton
-Brown tumors can occur in multiple areas within one bone
or as a polyostotic process
-At radiography, the lesions have variably well- or ill-defined
margins and may cause cortical expansion
-Concurrent bone changes associated with
hyperparathyroidism, such as generalized
demineralization of the medullary bones of the jaw and
loss of lamina dura around the roots of teeth, can help
differentiate brown tumors from other processes
-Serum abnormalities in hyperparathyroidism include
hypercalcemia, hypophosphatemia, and elevated levels
of parathyroid hormone

48. Brown tumor of hyperparathyroidism, lateral oblique radiograph shows a large, lucent
lesion in the mandibular body with expansion of the alveolar crest (arrows) and wispy
internal septa, “Windowing” of bone is seen (arrowheads) and is explained by lingual
expansion, because of the radiographic findings, mainly generalized demineralization
of the jaws and resorption of the lamina dura of the visualized teeth, a diagnosis of
hyperparathyroidism was suggested and was confirmed with serum assays

49. 4-Ameloblastoma :
-See later

50. 5-Eosinophilic Granuloma :
-Presents as a well-defined radiolucent lesion, with or
without reactive sclerosis on OPT; however, an
accompanying periosteal reaction is typically seen on CT
or CBCT
-Occasionally, this periosteal reaction may show a sunburst
appearance, suggesting a more aggressive biological
behavior, if the alveolar crest is invaded, a “scooped out”
appearance is seen; when the alveolar bone is
destroyed, a “floating tooth” appearance is observed
-EG is often associated with a soft tissue mass surrounding
the mandible and invading the muscles of mastication
-MRI findings include hypointense signal on T1,
hyperintense signal on T2 and marked enhancement
after intravenous gadolinium

51. Histologically proven eosinophilic granuloma, a OPT-like curved thick slab reconstruction, b axial CT
bone window and (c) 3D reconstruction from CT data set show a well-defined radiolucent lesion
(arrows) located in the angle of the mandible, sharply delineated slightly sclerotic borders,
periosteal reaction (dashed arrow). d PET/CT showing that high FDG uptake within the posterior
mandible and perimandibular soft tissues (arrow), e Axial T2 and f sagittal T1+C show a large
extraosseous component (arrows) with invasion of the masseter muscle. Close vicinity to the
submandibulat gland. Note high signal intensity on T2 and strong enhancement after gadolinium,
g Fused T2 and b 1,000 showing restricted diffusion, h ADC map showing a moderately low ADC
value (arrow) within the lesion, note inflammatory edema around the lesion with high ADC values
(asterisk)

52. 6-Giant Cell Granuloma :
-The typical radiological appearance is that
of a multilocular (less often unilocular)
well-defined radiolucent lesion
-On MRI, GCG has a homogeneous or
slightly heterogeneous intermediate signal
on T1, T2 and STIR and shows moderate
to strong contrast enhancement on T1+C

53. Central giant cell granuloma in a 14-year-old girl with progressive swelling over
the anterior mandible, cross-sectional occlusal radiograph shows an
expansile, corticated, lucent lesion in the anterior mandible with undulating
margins and wispy internal septa, displacement of teeth is present, and the
lesion crosses the midline

54. Central giant cell granuloma in a 34-year-old man, CT scan (bone
windowing) demonstrates a cystic lesion (arrows) within the
mandible. Note the erosion of the mandibular cortex

55. 7-Fibrous Dysplasia :
-At imaging, fibrous dysplasia is seen as a
heterogeneous lesion with ground-glass
attenuation and a wide, ill-defined
transition zone, a feature that helps
differentiate it from ossifying fibroma
-Its cortex remains intact and is often
thickened and sclerotic

56. Fibrous dysplasia in a 28-year-old man, CT+C demonstrates an
expansile lesion containing numerous unorganized bone trabeculae
(arrow) within the left mandibular body

57. Monostotic fibrous dysplasia, (a) Axial CT image shows an expansile lesion with
heterogeneous ground-glass attenuation, the transition zone that separates clearly
normal bone from abnormal bone is wide and ill defined, and marked cortical
thickening is seen along the lingual mandibular cortex (arrows), a finding more
commonly seen in fibrous dysplasia than ossifying fibroma, (b, c) Sagittal
reformatted (b) and volume-rendered (c) CT images show that expansion of the
lesion (arrows) is greater in the longitudinal direction than in the transverse expansion

58. Polyostotic (craniofacial) fibrous dysplasia, sagittal reformatted (a) and volume-
rendered (b) CT images show diffuse expansion of multiple facial and
cranial bones, which demonstrate ground-glass attenuation, a finding
indicative of fibrous dysplasia

59. b) Benign Tumors :
1-Ameloblastoma
2-Odontoma
3-Jaw Osteoma
4-Ossifying Fibroma
5-Cementoblastoma
6-Osteoblastoma

60. 1-Ameloblastoma : (Adamantinoma)
-Commonest in the mandible, usually near angle
-Slow growing painless mass
-Well defined unilocular or multilocular expansile
radiolucent lesions (“soap bubble” or
“honeycomb” appearance) with sclerotic border
-Large mass will cause jaw expansion with cortical
perforation

61. Ameloblastoma in a 20-year-old man, CT scan demonstrates a
multiloculated cystic lesion (arrow) within the left mandible, the
crown of an impacted tooth (arrowhead) identified within the lesion
is a clue to the diagnosis

62. 51-year-old woman with ameloblastoma, axial bone algorithm (A) and coronal soft-tissue
algorithm (B) CT+C and volume-rendering 3D CT image (C) show well-circumscribed,
slightly lobulated, expansile radiolucent lesion (arrows, A and C) in posterior body of
mandibular ramus, significant cortical thinning and remodeling are seen particularly in
lingual cortex, there are cortical defects on both buccal and lingular aspects of
mandible, note that nodular solid components show mild enhancement

63. Histologically proven multilocular ameloblastoma, a Axial bone window CT image, b 3D
reconstruction, frontal view, c T1, d T1+C show multilocular expansile radiolucency
with characteristic “soap bubble” appearance (asterisks) and major facial
deformation, cystic components with variable signal intensity on the unenhnanced T1
suggesting variable protein content, note variable enhancement of solid components
ranging from thin enhancing walls to thick enhancing solid portions (arrows)

64. Recurrent multilocular ameloblastoma, OPT showing a well-defined,
multilocular radiolucency (arrows) with sclerotic borders

65. 2-Odontoma :
-A developmental malformation or hamartoma consisting of
dental hard tissues or tooth-like structures
-Forming between the roots of teeth, the tumor is initially
radiolucent but evolves to contain small calcifications,
eventually, the tumor forms a radiopaque mass with a
lucent rim
-The WHO classification scheme further subdivides
odontomas into compound and complex types,
depending on their composition compared with normal
teeth, compound odontomas have radiographically
identifiable tooth components (abortive teeth), whereas
complex odontomas contain multiple masses of dental
tissue with amorphous calcifications
-Most odontomas can cause impaction or resorption of
adjacent teeth

66. Odontoma in three patients, (a) 3D volume-rendered CT image obtained in a child shows
several simple odontomas (arrows) that resemble supernumerary teeth, (b) Axial CT
shows multiple small toothlike structures (arrows), a finding indicative of a compound
odontoma, (c) Sagittal reformatted CT image shows a conglomerate mass of enamel
and dentin surrounding the crown of the tooth (arrows), a finding indicative of a
complex odontoma, a low-attenuation halo is also seen, a finding that may help
differentiate compound odontoma from osteoma

67. Panoramic radiograph shows the lesion as a well-defined radiopacity
surrounded by a radiolucent halo with secondary inferior
displacement and oblique horizontal impaction of the right
mandibular second premolar

68. Compound odontoma in a 28-year-old woman, Panorex image
demonstrates a focus of radiopaque enamel surrounded by a thin
radiolucent follicle (arrow), note the impacted tooth (arrowheads)
deep to the odontoma

69. Complex odontoma

70. 3-Jaw Osteoma :
-A benign bone forming tumor
-Usually slow growing and painless
-Affects the mandible more commonly than
the maxilla
-Gardner’s syndrome : multiple osteomas
with familial adenomatous polyposis

71. Osteoma in two patients, (a) Axial CT image shows a well-circumscribed sclerotic mass
with smooth margins in the mandibular ramus (arrows), the mass is associated with
mild bone expansion. No low-attenuation halo is seen, in the absence of bone
expansion, it may not be possible to differentiate osteoma and idiopathic
osteosclerosis, (b) Sagittal volume-rendered CT image obtained in a different patient
shows an osteoma (arrowheads) in the posterior mandibular body and ramus with
associated expansile simple bone cysts (arrows)

72. 4-Ossifying Fibroma :
-Also known as cemento-ossifying or cementifying
fibroma, contains fibrous tissue with varying
amounts of bony trabeculae
-The encapsulated, well-circumscribed lesion can
appear radiolucent, radiopaque, or with mixed
opacity depending on the degree of calcification
-With maturation, the lesion becomes more
radiopaque
-Although the lesion is similar in appearance to
fibrous dysplasia, its radiolucent boundary
allows some distinction

73. Ossifying fibroma in a 33-year-old woman, CT scan reveals a circular,
partially calcified lesion (arrow) within the mandible. Note the
internal ground-glass calcifications

74. Ossifying fibroma, axial CT images obtained in two different patients
show well-defined, focally expansile, sharply marginated lesions
with predominantly ground-glass attenuation, the presence of a
narrow zone of transition (arrows) helps differentiate ossifying
fibroma from fibrous dysplasia

75. 5-Cementoblastoma :
-Rare benign periapical lesion, represents
less than 1% of all odontogenic tumors,
90% develop in the molar or premolar
region
-At imaging, cementoblastoma appears as a
periapical, sclerotic, sharply marginated
lesion with a low-attenuation halo, they
directly fuse to the root of the tooth

76. Cementoblastoma, Bite-wing radiograph obtained in an adult
patient (a) and coronal CT image obtained in a 34-year-old
woman (b) show a periapical sclerotic lesion with sharp margins and
a lucent or low-attenuation halo (arrows) that is fused to the root of
the tooth, cementoblastoma arises in the molar or premolar region
in 90% of case

77. 6-Osteoblastoma :
-Uncommon and has a predilection for the
posterior mandible, affecting mainly young
people with a mean age below 20 years
-The radiological presentation comprises an ill-
defined (rarely well-defined) radiolucent or mixed
radiolucent-osteosclerotic lesion, the tumor
usually measures less than 4 cm and may be
partially calcified, the borders are typically
coarse and sclerotic
-Osteoblastoma has an expansile growth pattern
and may cause teeth displacement but typically
never leads to fusion with cementoma, a feature
allowing differentiation from cementoblastoma

78. Osteoblastoma, a OPT, b Axial CT with bone window, c Sagittal
oblique T1+C fat-saturated shows ill-defined radiolucent lesion
(arrows in a and b) with coarse sclerotic borders and calcifications
(dashed arrow). Major contrast enhancement (arrow in c)

79. c) Malignant Tumors :
1-Primary Odontogenic Tumors : rare
-Odontogenic carcinoma
-Odontogenic sarcoma
2-Primary Nonodontogenic Tumors :
-Osteosarcoma
-Chondrosarcoma
-Ewing's sarcoma
-Multiple myeloma
3-Metastases :
-Carcinomas, 85% (breast, lung, renal)
-Sarcomas

80. 24-year-old man with squamous cell carcinoma most likely derived from keratocystic odontogenic
tumor, axial (A) and volume-rendering 3D (B) CT images obtained using bone algorithm show
large radiolucent lesion (arrows) within posterior body of left mandible with associated cortical
break, note periosteal reaction, which may suggest aggressiveness of lesion or superimposed
infection, lesion (arrowhead, B) contains crown of unerupted third molar, C, Fused PET/CT
image shows intense FDG uptake associated with left mandibular mass (arrow); this finding
suggests malignancy

81. 16-year-old boy with ameloblastic carcinoma, axial (A) and volume-rendering 3D (B) CT
images show large destructive radiolucent lesion (white arrowheads) centered in
posterior body extending to manibular ramus, significant cortical destruction, and root
erosion that significantly displaces second molar (black arrowhead), (C) , Axial T1+C
fat-suppressed shows heterogeneously enhancing lesion (white arrowheads) with
regions of decreased signal

82. Ameloblastic carcinoma in a 17-year-old boy, (a) CT+C (bone
windowing) shows a multiloculated, enhancing soft-tissue mass
(arrows) with adjacent bone destruction, (b) Axial T1+C
demonstrates the enhancing soft-tissue mass (arrows)

83. Osteosarcoma in a 41-year-old man, (a) CT scan reveals osteoblastic changes
(arrows) within the right mandibular body, note the abnormal soft-tissue
ossification (arrowhead), (b) T1+C demonstrates an ill-defined lesion
(arrow) arising from periosteum, note the decreased marrow signal intensity
(arrowhead) involving the entire right mandibular body

84. Multiple myeloma in a 67-year-old man, (a) Panoramic reformatted CT
image demonstrates sclerotic (arrow) and lytic (arrowhead) lesions
in the mandible, (b) Axial T1 shows loss of the marrow fat within the
right mandibular angle (arrow) and mandibular foramen
(arrowheads)

85. Metastatic hepatocellular carcinoma in a 61-year-old man, CT+C
demonstrates an expansile, osteolytic mass (arrows) within the right
mandibular body

86. d) Mandibular Osteomyelitis :
-Osteomyelitis is much more common in the mandible than
the maxilla
-Most patients with mandibular osteomyelitis have a history
of antecedent dental caries or dental extractions, other
causes of osteomyelitis include dental or mandibular
fractures
-Chronic osteomyelitis, which is characterized by a duration
longer than 1 month, may be complicated by sinuses,
fistulae, osseous sequestra, or pathologic fractures. Risk
factors for osteomyelitis include impaired immunity, as
occurs in insulin-dependent diabetes mellitus,
alcoholism, and malnutrition; conditions that affect
mandibular blood supply, such as sickle cell disease and
collagen vascular diseases and radiation therapy; and
bone conditions, such as osteopetrosis
-Imaging findings of mandibular osteomyelitis include
cortical interruption, sclerotic sequestra in low-
attenuation zones, periosteal new bone formation, and
areas of gas attenuation

87. Acute suppurative osteomyelitis in a 44-year-old woman, CT scan
(bone windowing) demonstrates a nonexpansile, osteolytic lesion
(arrow) within the right mandible, perimandibular soft-tissue
inflammatory change (arrowheads) is also present

88. Osteomyelitis after tooth extraction, a OPT. b CT+C with bone window settings, c 3D reconstruction
show ill-defined osteolytic area (asterisks) extending into the ascending ramus of the mandible,
with cortical destruction (arrows in band c), d Axial T1-weighted image before (d) and after (e)
injection of gadolinium, hypointense signal of the mandible (arrows in d) due to marrow edema
and strong enhancement (arrows in e) due to hyperaemia, myositis of the masseter muscle (thick
dashed arrow) and streaky enhancement of the subcutaneous fat and platysma muscle (thin
dashed arrow) suggesting a phlegmon

89. Mandibular osteomyelitis in two patients, (a) Axial CT image shows sclerotic
sequestrum (arrow) with a surrounding low-attenuation zone and a sinus
tract through the buccal lingual cortex (arrowhead), axial (b) and coronal
reformatted (c) CT images show cloaking periosteal new bone formation
(arrows), a finding referred to as “onion skinning,” and sequestrum
(arrowhead)

90. Chronic osteomyelitis in a 47-year-old man, CT scan reveals an
osteolytic lesion (arrow) containing a bony sequestrum (arrowhead)
within the left mandibular body

91. *Proliferative periostitis :
-Is a lamellated pattern of periosteal new bone reaction that
produces focal bone expansion
-It most commonly occurs in children or young adults in the
molar or premolar regions of the mandible
-Underlying causes include dental caries with periapical
inflammatory disease, periodontal infection, fracture, and
nonodontogenic infection
-Periosteal proliferation is usually maximal along the inferior
mandibular and buccal cortices. Most cases are unifocal

92. Proliferative periostitis in a child. Axial (a) and volume-rendered (b) CT
images show focal mandibular buccal cortical expansion by
lamellated periosteal new bone formation (arrows)

93. *Primary chronic osteomyelitis :
-Is a nonsuppurative inflammatory process; its cause is
unknown
-It has multiple names, including diffuse sclerosing
osteomyelitis, chronic osteomyelitis with proliferative
periostitis, periostitis ossificans, nonsuppurative
osteomyelitis, and osteomyelitis sicca
-Has no acute phase and manifests with insidious jaw
swelling and normal mucosa
-Its occurrence is unrelated to dentition status, and it peaks
in childhood or early adolescence and after age 50
-Absence of a fever and leukocytosis are characteristic,
and associated teeth are typically vital
-At imaging, it may initially appear as a poorly marginated
lesion with progressive sclerosis, scattered osteolysis,
bone expansion, and an “onion skin” periosteal reaction
-In chronic cases, diffuse sclerosis predominates, a finding
that may cause it to be confused with fibrous dysplasia
or Paget disease

94. Sclerosing osteomyelitis in a 10-year-old boy, CT scan shows diffuse
sclerotic changes with expansion of the left mandibular body
(arrows), note the diffuse soft-tissue swelling (arrowheads)

95. Long-standing primary chronic osteomyelitis in an adult, cropped and
reconstructed CT panorex image shows diffuse mandibular
sclerosis with fluffy periosteal new bone formation (arrows) at the
mandibular angle

96. e) Temporomandibular Joint (TMJ) :
1-Disc Displacement
2-Degenrative Changes

97. 1-Disc Displacement :
-Pain, clicking and locked jaw occur
-The disc displacement is categorized based on the relation
of the displaced disc with mandibular condyle
-The displacement can be anterior, anterolateral,
anteromedial, lateral, medial and posterior
-The most common pattern of disc displacement are either
anterior and anterolateral accounting for more than 80%
of the causes
-The disc displacement can be subclassified as anterior
displacement with reduction (ADR) or anterior
displacement with no reduction (ADNR) based on
restoration of a normal relationship between the condyle
and the disc on mouth opening

98. Schematic of the TMJ in a closed mouth position
and sagittal projection of a closed jaw. 1,
Mandibular head; 2, articular eminence; 3,
disk (3a, anterior band; 3b, intermediate
zone; 3c, posterior band); 4, bilaminar
zone; 5, lateral pterygoid muscle with
interposed fat tissue (yellow in schematic)
(5a, superior head; 5b, inferior head); 6,
superior joint space; 7, inferior joint space
Sagittal of a normal TMJ with jaw in closed
position.1, Mandibular head; 2, articular
fossa; 3, disk (3a, anterior band; 3b,
intermediate zone; 3c, posterior band); 4,
bilaminar zone; 5, lateral pterygoid muscle

99. Schematic of the TMJ in an open mouth position and
sagittal projection. 1, Mandibular head; 2, articular
eminence; 3, superior joint space; 4, inferior joint
space; 5, disk (5a, anterior band;5b, intermediate
zone; 5c, posterior band); 6, bilaminar zone; 7,
lateral pterygoid muscle with interposed fat tissue
(yellow)
Sagittal of a normal TMJ with the jaw in an open
position. Note the bow-tie shape of the disk in the
sagittal projection. 1, Mandibular head; 2, articular
eminence; 3, disk (3a, anterior band; 3b,
intermediate zone; 3c, posterior band) ; 4, bilaminar
zone; 5, lateral pterygoid muscle

100. Normal anatomy, sagittal proton density weighted closed mouth and open mouth view of
magnetic resonance imaging, A: on the closed mouth view, the disk is located
posterior to the articular eminence (the letter, a), it can be noted that the “bow-tie”
shape of the disk: thicker anterior band (red arrow) and posterior band (white arrow)
with a thinner central zone (orange arrow), bilaminar zone (BZ) is located posterior to
the posterior band, it can also be noted that the inferior joint compartment (white
arrowhead) between the disk and the mandibular condyle (the letter, b) and superior
joint compartment (red arrowhead) between the articular eminence and the disk; B:
on the open mouth view (in a different patient), the thinner intermediate zone (red
arrow) of the disk is interposed between the articular eminence (the letter, a) and the
condylar head (the letter, b) in a “bow-tie” fashion, orange arrowhead demonstrates
temporal lamina and black arrowhead indicate inferior lamina

101. Anterior displacement with reduction, A: Sagittal proton density MRI in the
closed mouth position demonstrates anterior displacement of the disk
(arrow) in front of the mandibular condyle (the letter, c), B: Sagittal proton
density weighted MRI in the open mouth position demonstrates reduction of
the disk (arrow) between the articular eminence (the letter, a) and the
mandibular condyle (the letter, c)

102. Anterior displacement with no reduction, A: Sagittal proton density MRI in the
closed mouth position demonstrates anterior displacement of the disk
(arrow) related to the articular eminence (the letter, a) and anterior to the
mandibular condyle (the letter c), B: Sagittal proton density MRI in the open
mouth position demonstrates no reduction of the disk (arrow) between the
articular eminence (the letter, a) and the mandibular condyle (the letter, c)

103. 2-Degenrative Changes :
-Radiographic findings are similar to those
of osteoarthritis in other joints :
1-Joint space narrowing
2-Subchondral sclerosis, spurring &
pseudocyst formation
3-Deformity
4-Avascular necrosis

104. Degenerative changes, sagittal reformation of the axial dataset
demonstrates deformity of the mandibular condyle (the letter, c),
extensive sclerosis of the articular eminence (the letter, a) and
severe loss of joint space