important points only are covered..

3. Introduction
Classification
Anatomical radiolucencies
Involving mandible
Involving maxilla
Involving both jaws
Unilocular radiolucencies
Multilocular radiolucencies
References

4. What is radiolucency ?
It express that the region/area/object didn’t absorb
the radiation but is transparent/translucent thus
more radiation reaches the sensor/film leading to
a darker area.

5. What is unilocular radiolucency?
From the word uni: means one and lucular
means lobes, it means the lesion appears
as one mass.

6. Multilocular radiolucency is produced by multiple adjacent,
frequently coalescing & overlapping pathologic compartments
in bone.
True multilocular lesion contains two or more pathologic
chambers partially separated by septa of bone.
Soap bubble appearance-
Lesions consists of several circular compartments that vary
in size & usually appear to overlap

7. Honeycomb-
Lesions whose compartments are small & tend to be
uniform in size
Tennis racket-
Lesions that are composed of angular rather than rounded
compartments that result in formation of more or less septae.
These compartments tend to be triangular rather, rectangular
or square

8. UNILOCULAR RADIOLUCENCIES

9. Singapore Med J 2008; 49(2) : 165

11. o Structures relatedto Mandible
• Mandibular Foramen
• Mandibular Canal
• Mental Foramen
• Lingual Foramen
• Submandibular Fossa
• Mental Fossa

12. o Structures relatedto Maxilla
• Intermaxillary Suture
• Incisive Foramen
• Nasal Cavity
• Nasolacrimal duct/canal
• Maxillary sinus
o Structures common to bothJaws
• Periodontal ligament space
• Marrow Space
• Nutrient Canal
• Follicular Space

13. MANDIBULAR FORAMEN
Usually situated just above the mid point in the
medial surface of the ramus & just posterior to the
mid point between the anterior & posterior borders.
Seen on panographic & lateral oblique films
Outline of foramen varies from triangular to oval to
funnel shaped
Radiographic image is usually upto 1 cm in
diameter
It is associated with relatively radiolucent
mandibular canal that passes from it in an
anteroinferior direction
STRUCTURES RELATED TO MANDIBLE

14. MANDIBULAR FORAMEN
Lingula may be detected as a triangular radiopacity of variable density
at the foramen’s anterior border
These associated structures, with mandibular canal & lingula, can be
mistaken for pathology

15. MANDIBULAR CANAL/ INFERIOR DENTAL CANAL:
Largest of the nutrient canals
Seen on panoramic or periapical radiographs of molar region
Appears as relatively radiolucent channel bounded by definite, thin
radiopaque lines (cortical bones) through out its length
Its course can be followed anteroinferiorly to a point where it
frequently appears to sweep upward to meet the mental foramen

16. MENTAL FORAMEN
Anterior limit of mandibular canal
Mandibular canal send off the mental
canal in the premolar region
This smaller, short canal runs in superior
buccal direction, terminating with the
mental foramen
It is usually located on the radiograph in
the vicinity of premolar apices.
It may be mistaken for periapical pathosis
when it occurs at the apex of premolars

17. LINGUAL FORAMEN
Seen in relation to lower central
incisors often on periapical views
Located well below the apices of
these teeth in the midline
Seen as radiolucency measuring
usually 1-2mm in diameter surrounded
by prominent radiopaque ring of cortical
bone
Occasionally 2 or more foramina are
seen.

18. SUBMANDIBULAR GLAND FOSSA
Submandibular fossa is concave area on the
lingual side of the mandible below the molar area
which accommodates the Submandibular salivary
gland
Lies between inferior alveolar canal & lower
cortical margin of mandible
This is seen as relatively radiolucent area with
sparse trabecular pattern which is sharply limited
superiorly by the lower border of mylohyoid ridge
and inferiorly by lower border of mandible
Shape is round, ovoid or triangular (rarely)
Rarely occurs bilaterally

19. MENTAL FOSSA
Depression on the labial aspect of
midline of mandible just above the
mental tubercle
Due to relative thinness of bone
over in this area, it may be seen as
radiolucency over the incisor roots
which may be mistaken for
periapical pathology

20. MIDLINE SYMPHYSIS
Seen on the midline of the
mandible of infants
Seen as radiolucent line
which may be misinterpreted
for fracture line
Symphysis usually ossifies
by age of 1 year & then is no
longer apparent

21. MEDIAL SIGMOID DEPRESSION
It is a radiolucency that appears below & just anterior to greatest
depth of sigmoid notch of ramus
Seen on approximately 10% of panoramic radiographs
It is defined by temporal crest & crest of mandibular neck
Its degree of expression is variable depending upon prominence of
these two crests.

22. SUBLINGUAL GLAND DEPRESSION
First reported by Richard & Ziskind (1957)
It may develop to accommodate sublingual
salivary gland tissue that lies in close proximity
to the lingual cortex of mandible in canine region
Most often associated with canines, followed
by incisors & 2nd premolars (rare), in apical 1/3rd
of root
Average size-1.2 cm
Trabeculation may be present within
radiolucency
Have punched out appearance or corticated
margin

23. STRUCTURES RELATED TOMAXILLA

24. AIRWAY SHADOW
Bilateral, relatively radiolucent
Seen on panoramic, lat oblique & cephalomatric radiographs
Results from lack of soft tissue between he posterolateral surface of
tongue & region of soft palate & posterior pharynx

25. INTERMAXILLARY SUTURE
Intermaxillary/ median suture
between right & left maxillary bones,
can be identified as thin vertical
radiolucency in midline between central
incisors
Usually delineated by two thin,
vertical radiopaque lines (cortical
bone).
Generally fuses later in life & then no
longer seen on radiograph.

26. INCISIVE FORAMEN,
Incisive foramen (anterior palatine
foramen) frequently shows as a round,
oval, diamond shaped or heart shaped
radiolucency that is well defined on
occlusal & periapical radiographs
The position of foramen on radiograph
ranges from between the roots of central
incisors, close to alveolar ridge to the
level of apices.
Variability in position of foramen on
radiograph is due to the angulation of the
rays & position of foramen

27. SUPERIOR FORAMINA OF
INCISIVE CANALS
On radiograph they are seen as two
round or oval radiolucent areas above
the apices of central incisors in the
floor of nasal cavity near its anterior
border & both sides of nasal septum
In IOPA their image be
superimposed over apices incisors,
which may be misinterpreted as
periapical pathosis

28. NASOLACRIMAL DUCT/ CANAL
Nasal & maxillary bones form The nasolacrimal canal
Seen on maxillary occlusal radiograph , projected onto the posterior
hard palate near the 1st or 2nd molar as well defined radiolucency
bilaterally well defined by sharp radiopaque borders.
On periapical radiographs it may be seen in the region above the
apex of canine, especially if steep angulation is used.

29. MAXILLARY SINUS
Appear as well defined radiolucency with
thin, sharp radiopaque borders
It shows considerable variation in size
They enlarge in childhood, achieving
mature size by age of 15 to 18 years
Floors of maxillary sinus & nasal cavity are
seen at approximately same level at age of
puberty in radiograph
In adults sinuses are usually seen to
extend from the distal aspect of canine to
the posterior wall of maxilla above tuberosity

30. In older individuals it may extend farther
into the alveolar process & may extend
upto the alveolar ridge in absence of
teeth

31. STRUCTURESCOMMONTOBOTHJAWS

32. MARROW SPACE
Marrow spaces between trabeculae of
bone appear as radiolucent region
Varies greatly in shape, size &
distribution
Radiographically, in maxilla, they are
generally relatively uniform in size
In mandible marrow spaces are smaller
& more numerous in the anterior portion &
larger in the posterior portion

33. In some persons trabecular
spaces just above & below the
roots of molars are so large &
trabeculae so sparse that the
combined appearance may
resemble & be misinterpreted as
cysts & other pathosis
These are referred as focal
osteoporotic bone marrow
defects

34. NUTRIENT CANAL
Appear as ribbonlike
radiolucencies of fairly uniform width
Carry neurovascular bundles
Seen more often on periapical
mandibular radiographs
Canals become more marked
when teeth are missing

35. PERICORONAL/ FOLLICULAR SPACE
The crowns of unerupted teeth are
surrounded by dental follicle- remnant of
reduced enamel epithelium
It is composed of soft myxomatous to
dense collagenous fibrous connective
tissue or cords of odontogenic epithelium
On radiograph it appears as
homogeneous radiolucent halo

36. Surrounded by thin outer
radiopaque border representing
compact bone continuous with
lamina dura
Radiolucent halo merges with
periodontal ligament space
Width of halo varies because of
varying thickness of the follicles &
accumulation of fluid between the
capsule of reduced enamel
epithelium & tooth crown
Normal follicular space – 1.5 to 2 mm

38. PERIAPICAL ABSCESS
The primary abscess develops in a periapical region that is normal
on radiographic examination.
The infection is usually acute and exudative, involving the
periodontal tissues at the apex of the tooth with necrotic pulp.
The infection and inflammation in the apical area forces the tooth
slightly from its socket, creating an increased periodontal ligament
space around the entire root that is usually apparent on the
radiograph.
The secondary abscess may be of the chronic or the acute type

39. Related tooth shows features such as deep restorations, caries,
narrowed pulp chamber, or canals which suggest that the pulp is non-
vital.
The roots of these teeth may show resorption at the apex.
The tooth is painful on percussion and the patient complains that it
seems ‘high’ to bite on.
Tooth doesnot respond to electric pulp test.
The tooth may demonstrate increased mobility.
In untreated cases the abscess may penetrate the cortical plate at
the thinnest and closest point to the apex and form a space infection
in the adjacent soft tissue.

40. Periapical radiolucency is a feature of
the secondary abscess.
The radiolucency may vary from small to
quite large to involve much of the jaw.
The initial periapical lesion may cause
expansion of cortical plate.
 In case of acute lesion the margins of
the radiolucency may be well defined with
possibly a hyperostotic border.
The borders are poorly defined in case
of chronic conditions. Sometimes the
radiolucency is represented as a blurred
area of somewhat lessened density than
that of surrounding bone.
Radiographic
Features

41. Represents between 69.7% & 94% of all pulpoperiapical lesions
It is a result of successful attempt by the periapical tissue to
neutralize & confine the irritating toxic products that are escaping
from the root canal
 Continual discharge of chronic irritating products from the canal
into the periapical tissue is sufficient to maintain a low grade
inflammation in the tissues which results in formation of periapical
granuloma
PERIAPICAL GRANULOMA

42.  Well circumscribed radiolucency somewhat
rounded & surrounding apex of tooth
May be surrounded by thin radiopaque
(hyperostoic ) border
Cannot be differentiated from radicular cyst
radiographically alone
Cysts tend to be larger than granulomas but
differentiation on basis of size is not possible as
some cysts are small & granulomas large
Granulomas are rarely larger than 2.5cm in
diameter
Involved tooth is non vital & asymptomatic
Radiographic
Features

43.  Synonyms-
Periapical cyst
Apical periodontal cyst
Dental cyst
Most common type of cyst in jaw
It results when cell rests of Malassez in the PDL are stimulated to
proliferate & undergo cystic degeneration by inflammatory products
by non vital tooth
Usually asymptomatic unless secondary infection occurs
Incidence is greater in 3rd to 6th decade with slight male predilection
RADICULAR CYST

44.  Most radicular cysts involve apices of permanent teeth
58% involve lateral incisors
History & clinical features are similar to those of periapical
granuloma
Studies by Lalonde show that such a lesion is more likely to be a
radicular cyst if the periapical radiolucency tends to be atleast 1.6cm
in diameter

45.  An untreated cyst may enlarge slowly & cause expansion of
cortical plates.
In these cases a domelike swelling is seen on the alveolus over the
periapical region of alveolus of involved tooth
Swelling is initially bony hard on palpation but later it may
demonstrate crackling sound (crepitus) as cortical plate is thinned
In these cases swelling is rubbery & fluctuant because of cystic
fluid

46. Radiographic
Features LOCATION
Most common site- maxilla (60%)
especially incisors (58%) & canines
In deciduous teeth most commonly molars
are involved
Epicenter is located at the apex of
nonvital tooth
Occasionally it appears on the mesial or
distal surface of root, at the opening of
accessory canal, or infrequently in a deep
periodontal pocket

47.  PERIPHERY & SHAPE
Usually has well defined cortical border
When cyst becomes secondarily infected due to inflammatory
reaction of surrounding bone, cortex may be lost or become more
sclerotic
Outline is usually curved or circular

48.  EFFECT ON SURROUNDING STRUCTURES
If cyst is large, displacement & resorption of roots of adjacent teeth
may occur
Outer cortical plate of maxilla or mandible my expand in curved or
circular shape
Cyst may displace the inferior alveolar canal in an inferior direction.

49. Periapical granuloma & radicular cyst cannot be
distinguished radiographically alone, although
radiolucency with well defined corticated border more
than 2cm diameter, it is more likely to be cyst.
Differential
Diagnosis

50. Periapical cementoosseous
dysplasia:
Difficult to distinguish
radiographically from periapical
granuloma & radicular cyst in its
early lytic stage. Tooth is vital in
PCOD
Lower teeth especially incisors more
commonly involved

51. Traumatic bone cyst: Teeth associated
with lesion are vital
Most commonly seen in mandibular region
in molar, premolar & incisor region
Periapical granuloma does not have
predilection for lower jaw & more
common in anterior region
Lamina dura is intact in traumatic bone
cyst

52. Synonym- Follicular cyst
Most common type of cyst that is formed around
crown of an unerupted tooth
Begins with accumulation of fluid in the layers of
reduced enamel epithelium or between the epithelium
and the crowns of unerupted or supernumerary tooth
Typically patient has no pain or discomfort

53. Location
Mandibular 3rd molar or maxillary
canines are most commonly involved
Epicenter is found just above the
crown of involved tooth
Cyst is attached to the CEJ
Some cyst are eccentric
developing from the lateral aspect
of crown so that they occupy an
area besides the crown instead of
above the crown
Radiographic Features

54. Periphery and Shape
It has well defined cortex
with a curved or circular
outline
Cortex may be missing if
infection is present
Internal Structure
Completely radiolucent
except the crown of involved
tooth

55. Effects on Surrounding Structure
Displaces tooth involved usually in apical direction
It may also resorb the adjacent teeth
The floor of maxillary antrum may be displaced as the cyst
invaginates the antrum & displace inferior alveolar canal in inferior
direction
It tends to expand outer cortex of involved jaw

56. Hyperplastic follicle
Size of normal follicular space is 1.5-2mm
If follicular space exceeds 5mm, it is more likely
to be dentigerous cyst.
Tooth displacement & expansion is associated with
dentigerous cyst
DIFFERENTIAL DIAGNOSIS

57. Odontogenic cyst
Sometimes associated with
unerupted tooth with lesion
present at pericoronal position
Does not cause expansion of
bone
Less likely to resorb teeth
May attach further apically on
root than at CEJ

58. Ameloblastic fibroma
May be present around the
crown of an unerupted tooth
Difficult to differentiate
radiographically

59. Unicystic ameloblastoma
Unilocular ameloblastoma
located around the crown of an
unerupted tooth is difficult to
differentiate
Causes apical displacement of
teeth

60. Adenomatoid odontogenic
tumour
When completely radiolucent
& associated with impacted
tooth difficult to
differentiate
Attached apical to CEJ

61. Synonyms
Mural Ameloblastoma
Cytogenic Ameloblastoma
Cystic variant of Ameloblastoma
Cystic Ameloblastoma
Intracystic Ameloblastoma
Arises from the wall of cyst
2nd most frequently occurring pathologic pericoronal
radiolucency
Represents approximately 5% of all ameloblastomas

62. It is associated with following cysts
Dentigerous cysts (85%)
Residual cysts
Radicular cysts
Globulomaxillary cysts
Primordial cysts
Shortly after induction, the tumour begins as mural (within
wall)
When it infiltrates the connective tissue wall of cyst it invades
between the medullary spaces of bone. It than behaves like
conventional ameloblastoma.

63. Approximately 20% are associated with the crown of
mandibular 3rd molar.
Seen in younger age (average age- 21 years)
Associated with impacted, displaced tooth showing
incomplete root formation
Present as painless swelling

64. Mandible is more commonly involved
77% were in molar ramus region, 10% in premolar area, 13%
in symphysis
There is pericoronal radiolucency associated with an
unerupted mandibular 3rd molar
Associated teeth is displaced
RADIOGRAPHIC FEATURES

65. Adjacent erupted 2nd or 3rd molar may show knife edge
pattern of root resorption
Expansion is often present, which tends to be greatest on
buccal aspect
There may be perforation of anterior margins of ramus or at
retromolar pad area

66. SYNONYMS
Adenoameloblastoma
Ameloblastic adenomatoid tumour
AOT is uncommon, benign and noninvasive tumour
Makes up approximately 3% of all odontogenic tumours
CLASSIFICATION
Central
Follicular (73%)
Extrafollicular
Peripheral

67. Age- 2nd decade
Female predilection (2:1)
Follicular type is associated with unerupted
tooth
Unerupted teeth frequently associated with
tumour in order of frequency are maxillary
canine, lateral incisor & mandibular premolar
Presents as slow growing painless swelling

68. Location
75% occurs in maxilla especially in incisor-
canine- premolar region
Has follicular relationship with impacted
tooth but doesnot attach at CEJ, most often
canine is involved or sclerotic border
RADIOGRAPHIC FEATURES

69. Periphery
Lesion is well defined with
corticated or sclerotic border
Internal structure
1/3rd of cases show completely
radiolucent lesions
In rest radiopacities are
present within the lesion

70. Effect on surrounding structures
Causes displacement of teeth
Root resorption rare
May inhibit eruption of tooth
Expansion of jaw may occur

71. Dentigerous cyst
Associated with impacted teeth but
radiolucent lesion is more apical than CEJ
DIFFERENTIAL DIAGNOSIS
Odontogenic keratocyst
Difficult to differentiate pericoronal OKC
from AOT radiographically

72. Synonym
Soft odontoma
Soft Mixed Odontoma
Mixed Odontogenic Tumour
Fibroadmantoblastoma
Granular Cell Ameloblastic Fibroma

73. These are benign, true mixed odontogenic tumours
, containing nests & strands of odontogenic &
ameloblastic epithelium in primitive dental papilla
Calcified odontogenic structures are not present
Age – below 20 years
Manifests as painless, slow growing expansion &
displacement of involved tooth
May be associated with missing tooth

74. Location
Mandibular premolar- molar
region most common site
Tumour may involve ramus in
some cases
Common location is crest of
alveolar process or in follicular
relationship with an unerupted
tooth
RADIOGRAPHIC FEATURES

75. Periphery
Borders are well defined
& corticated
Internal Structure
More commonly present
as unilocular radiolucency
but may be multilocular
with indistinct curved
septa

76. Effects on Surrounding Structure
Large lesion can cause expansion of cortical
plates without bone destruction
Associated tooth may fail to erupt or
displaced apically

77. Hyperplastic Follicle
Dentigerous cyst
Not possible to differentiate either entity
radiographically from ameloblastic fibroma
DIFFERENTIAL DIAGNOSIS

79. Ameloblastoma
Cherubism
Odontogenic myxoma
Central hemangioma
Aneurysmal bone cyst
Central giant cell granuloma
Odontogenic keratocyst
Hyperparathyroidism

80. SYNONYM-
Admantinoma
Adamtoblastoma
Odontomes Embryolastiques
Epithelial Odontomes
It is true neoplasm of odontogenic epithelium, is a persistent,
locally invasive tumour; it has aggressive but have benign growth
characteristics

81. Represents about 1% of all odontogenic epithelial tumours & 11%
of all odontogenic tumours
Slight male predilection
More common in blacks
Age- 20 to 50 years
Slow growing
Frequently discovered on routine radiographs
Teeth in involved region may be displaced or become mobile

82. Location
About 80% develop in mandibular
molar– ramus region & may extend
into the symphyseal region
In maxilla 3rd molar area is involved
& extends in the maxillary sinus &
nasal floor
RADIOGRAPHIC FEATURES

83. Periphery
Well defined & delineated with
a cortical border
Border is often curved & in
small lesions it may be
indistinguishable from a cyst
Maxillary lesion are more ill
defined

84. Internal Structure
Varies from totally radiolucent to
mixed with bony septae creating
internal compartments
These septae are usually coarse &
curved & originate from the normal
bone that has been trapped within
the tumour

85. Internal Structure
Since ameloblastoma
frequently has internal cystic
components, these septae are
often remodeled into curved
shape giving a honeycomb or
soap bubble appearance
Generally loculations are larger
in posterior mandible than in
anterior part

86. Effects On Surrounding
Structures
Causes extensive root resorption & tooth
displacement
Common point of origin is occlusal to
tooth; teeth may be displaced apically
Occlusal radiograph may show cyst like
expansion & thinning of adjacent cortical
plate, leaving a thin eggshell of bone

87. In late stages perforation of bone into
surrounding soft tissues or anatomic spaces
occurs
Unicystic types may cause extreme
expansion of mandibular ramus

88. Odontgenic keratocyst
Grows along the bone without
expansion of bone
Differential diagnosis

89. Giant Cell Granuloma
Occurs anterior to molars
Younger age group
More granular & ill defined septae

90. ODONTOGENIC MYXOMA
Both more common in mandible
Ameloblastoma is common in molar- ramus region
Odontogenic myxoma in premolar & molar region & rare in ramus
Straight thin septa seen in odontogenic myxoma whereas curved coarse in
ameloblastoma
Ameloblastoma causes extensive root
resorption
Odontogenic myxoma tends to grow in
length of bone

91. Ossifying Fibroma
Septae are wide granular & ill defined

92. SYNONYM
Familial fibrous dysplasia
Cherubism is rare, inherited developmental abnormality that
causes bilateral enlargement of jaws, giving child a cherubic facial
appearance
It is inherited as autosomal dominant trait
It is composed of giant cell like granuloma- like tissue & does
not form bone matrix
Lesion regress with age

93. Age- 2- 6 years
Presents as painless, firm, bilateral enlargement of lower face.
Occasionally whole mandible is involved
Maxillary sinus, orbital floor & tuberosity region may be involved
causing stretching of skin of cheeks, which depresses the lower
eyelids, exposing thin line of sclera (eyes in heaven appearance)

94. Lesions grow slowly, expanding but not perforating cortex
Enlargement of submandibular lymph nodes may occur
By age of 8-9 years of age , growth of pathologic lesion may stop
At puberty lesion may begin to regress
Usually bony architecture returns to normal by age of 30 years

95. Location
Lesion is bilateral
Often both the jaws are affected
When present in only one jaw, mandible is
more commonly affected
Epicenter is always in posterior part of
jaws, in ramus of mandible, or tuberosity of
maxilla
Lesion grows in anterior direction
In severe cases may extend upto midline
RADIOGRAPHICFEATURES

96. Periphery
Well defined & in some instances corticated
Internal Structure
Fine granular bony & wispy trabeculae present giving a soap bubble appearance

97. Effects On Surrounding Structure
Expansion of maxillary & mandibular cortex occurs resulting in
severe enlargement of jaws
Maxillary lesion enlarges into maxillary sinus
Teeth are displaced in anterior direction as epicenter is placed in
posterior part of jaw
Degree of expansion can be severe resulting in destruction of
tooth buds & incipient follicles

98. GIANT CELL GRANULOMA
Internal structure has fine, wispy
trabeculae as in cherubism
Cherubism is bilateral with epicenter in
ramus
DIFFERENTIAL DIAGNOSIS

99. MULTIPLE ODONTOGENIC KERATOCYST
Cherubism shows bilateral symmetry with anterior displacement of
teeth & has multilocular appearance
DIFFERENTIAL DIAGNOSIS

100. SYNONYM
Myxoma
Myxofibroma
Firbomyxoma
Account for 3- 6% of odontogenic tumours
These are benign, intraosseous neoplasm that arises from
odontogenic ectomesenchyme & resemble mesenchymal portion of
dental papilla
Non encapsulated & tend to infiltrate the surrounding cancellous
bone

101. Age- 10 – 30 years
Slight female predilection
Slow growing painless lesion
If left untreated it grows large & may invade maxillary sinus
Recurrence rate – 25% (noncapsulated, poorly defined
boundaries, extension of nests or pockets of myxoid tumour into
trabecular spaces)

102. LOCATION
Most commonly affects mandible (3:1)
Occurs in premolar & molar areas & rarely in ramus & condylar
area
In maxilla, alveolar process in premolar & molar regions &
zygomatic process is involved
PERIPHERY
May be well defined & corticated or poorly defined (in maxilla)
RADiographicfeatures

103. INTERNAL SRTUCTURE
It may produce several pattern
Unicystic
Multilocular
Pericoronal
Radiolucent – radiopaque
Residual bone trapped within the bone remodels into curved or
straight, coarse or fine septae giving multilocular appearance

104. INTERNAL SRTUCTURE
Characteristically septae are
straight & thin (tennis racket or
step ladder appearance)
 but this pattern is rarely seen
Majority of septae are curved &
coarse, but finding one or two of
these straight septa helps in
identification

105. EFFECTS ON SURROUNDING
STUCTURE
Causes displacement & loosening of
teeth but rarely resorption
Lesion frequently scallops between
the roots of adjacent structure
Tendency to grow along the bone
without causing much expansion

106. AMELOBLATOMA
Both more common in mandible
Ameloblastoma is common in molar- ramus region
Odontogenic myxoma in premolar & molar region
& rare in ramus
Straight thin septa seen in odontogenic myxoma
whereas curved coarse in ameloblastoma
Ameloblastoma causes expansion of bone but
odontogenic myxoma grows along the length of
bone
Differential DIAGNOSIS

107. CENTRAL GIANT CELL GRANULOMA
Both occur in mandible but CGCG occurs
anterior to 1st molar
septae are ill- defined & wispy & some are
at right angles to the periphery
CGCG causes expansion of jaws

108. CENTRAL HEMANGIOMA
Mandible common site but posterior body ,
ramus & inferior alveolar canal is involved
Shows coarse trabecular pattern

109. OSTEOGENIC SARCOMAS
In odontogenic myxoma a small area of expansion with straight septae may be
projected over an intact bony cortex & give spiculated appearance resembling
osteogenic sarcoma
But outer cortex is destroyed in odontogenic sarcoma

110. Hemangioma is a proliferation of blood vessels
Most frequently noticed in skin & subcutaneous tissues
Central hemangioma is more commonly seen in vertebrae & skull
Rarely develops in jaws
Lesion may be developmental or traumatic in origin
More prevalent in females (2:1)
Age- 1st decade

111. Presents as slow, non tender expansion of jaws
It is bony hard in consistency
Pain, if present is probably throbbing type
Some tumours are compressible or pulsate & bruit may be detected
on auscultation
Anesthesia of skin supplied by mental nerve occurs
Bleeding may occur around gingiva around the neck of teeth

112. LOCATION
Mandible twice more affected than maxilla
Posterior body & ramus & within the inferior alveolar canal
Gives a cart wheel apperaence.

113. PERIPHERY
Periphery is well defined & corticated or
ill defined
Variation is related to the amount of
residual bone around the blood vessels
Formation of linear spicules of bone
emanating from the surface of the bone in
sunray- like appearance can occur when
hemangioma breaks through the outer
cortex & displace the periosteum

114. INTERNAL STRUCTURE
Multilocular appearance is due to
entrapment of residual bone trapped
around the blood vessels
Small radiolucent locules may
resemble marrow spaces surrounded by
coarse, dense & well defined trabeculae
These trabeculae produces honeycomb
pattern composed of small circular
radiolucent spaces that represent blood
vessels oriented in the same direction of
x- ray beams

115. Width of inferior alveolar canal, if involved, is increased & shape becomes
serpiginous
Phleboliths are formed when soft tissue is involved
They develop from thrombi that become organized & mineralized & consists of
calcium phosphate & calcium carbonate

116. EFFECTS ON SURROUNDING STRUCTURES
Roots of teeth are resorbed or displaced
Width of inferior alveolar canal, if involved, is increased & shape changes to serpiginous path
Mandibular & mental foramen may be enlarged
Involved bone may be enlarged & have coarse internal trabeculae
Developing teeth in contact with hemangioma may be larger & erupt earlier

117. •Characterized as false cyst as it does not have epithelial
lining
•Age- below 30 years
•Female predilection
•Usually presents as rapid bony swelling
•Pain is occasionally present
•Involved area may be tender on palpation

118. LOCATION
•Mandible is more commonly involved than maxilla (3:2) in molar
& ramus region
PERIPHERY & SHAPE
•Periphery is usually well defined & shape is circular.
Radiographic features

119. INTERNAL SRTUCURE
•Small initial lesion may show no evidence of an internal structure
•Often internal structure is multilocular
•Septa is wispy & ill- defined & perpendicular to outer expanded border
EFFECTS ON SURROUNDING STRUCTURES
•Causes expansion of outer cortical plates
•Displaces & resorbs teeth

120. CENTRAL GIANT CELL
GRANULOMA
Both have wispy, ill- defined trabeculae
Expansion of cortex is more in ABC than
CGCG
ABC is found in molar & ramus area whereas
CGCG in anterior to 1st molar region
DIFFERENTIALDIAGNOSIS

121. AMELOBLASTOMA
ABC causes cortical expansion &
displaces & resorbs tooth as in
ameloblastoma
Molar – ramus region common site
in both
Septae are curved, coarse & well
defined in ameloblastoma
Occurs in older age
DIFFERENTIALDIAGNOSIS

122. CHERUBISM
Both have ill defined, wispy trabeculae & causes expansion of jaws
But cherubism is multifocal & bilateral
DIFFERENTIALDIAGNOSIS

123. SYNONYM
Giant cell reparative granuloma
Giant cell lesion, giant cell tumour
Slow growing lesion
Affects mostly adolescents & young adults, usually below the age
of 20 years
Presents as painless swelling
Area is tender on palpation
Overlying mucosa is purple in colour

124. LOCATION
More common in mandible (2:1)
Epicenter of lesion is usually anterior to 1st molar, although large lesion can
extend posterior to ist molar
Most maxillary lesion arise anterior to canines
Lesions can cross midline
PERIPHERY
Well defined margin in mandible
Lesions in maxilla have ill defined borders
Radiographic features

125. INTERNAL STRUCTURE
Small lesions are completely
radiolucent
Larger lesion show subtle granular
pattern of calcification
Occasionally these calcifications
are organized into ill- defined wispy
septa which are at right angles to the
periphery of the lesion
Sometimes these septa are well
defined & divide the internal aspect
into compartments, creating a
multilocular appearance

126. EFFECTS ON SURROUNDING
STRUCTURES
Often displace & resorb teeth
Resorption of roots not common but
when it occurs, it may be profound &
irregular in outline
Lamina dura of involved teeth is absent
Inferior alveolar canal may be displaced
in an inferior direction

127. EFFECTS ON SURROUNDING STRUCTURES
Causes expansion of cortical boundaries of jaw
Expansion is uneven or undulating in nature, which may give
appearance of a double boundary when seen in occlusal radiograph
Outer cortical plate is destroyed in some cases & is seen more
often in maxilla

128. Differential diagnosis
AMELOBLASTOMA
Occurs posterior mandible
Younger age group
More curved, granular & well defined
septa

129. CHERUBISM
Internal structure has fine, wispy trabeculae as in cherubism
Cherubism is bilateral with epicenter in posterior part of jaw

130. ODONTOGENIC MYXOMA
Both occur in mandible but CGCG occurs
anterior to 1st molar
septae are sharper & straighter in OM
CGCG causes expansion of jaws

131. ABC
Both have wispy, ill- defined trabeculae
Expansion of cortex is more in ABC than CGCG
ABC is found in molar & ramus area whereas CGCG is anterior to
1st molar region

132. *OKC is a noninflammatory odontogenic cyst that arises from
dental lamina
*Accounts for about 1/10th of all cysts in the jaws
*Age- 2nd & 3rd decade
*Male predominance
*Usually asymptomatic
*Pain may occur with secondary infection
*Aspiration may reveal thick, yellow cheesy material (keratin)

133. LOCATION
*Site- posterior body of mandible (90% occur posterior to canine) &
ramus (> 50%)
*Epicenter is located superior to inferior alveolar canal
RADIOGRAPHIC FEATURES

134. PERIPHERY & SHAPE
*Cortical border is intact unless they have become secondarily
affected
*Has smooth round or oval shape

135. INTERNAL STRUCURE
*Most commonly
radiolucent
*In some cases curved
internal septa may be
present, giving lesion a
multilocular appearance

136. EFFECTS ON SURROUNDING
STRUCURES
*Grows along the internal aspect of jaws,
causing minimal expansion
*This occurs throughout the mandible except
for the upper ramus & coronoid process, where
considerable expansion may occur
*Can displace & resorb teeth
*Inferior alveolar canal may be displaced
inferiorly
*In maxilla, it may invaginate & occupy
maxillary antrum

137. Ameloblastoma
Both have scalloped margins
Ameloblastoma causes expansion of
bone
Differential diagnosis

138. Odontogenic myxoma
Both shows minimal expansion of bone
Straight septa present in odontogenic
myxoma

139. It is endocrine abnormality in which there is an excess of
circulating Parathyroid hormone (PTH)
It causes increase in serum calcium by two processes
An excess of serum PTH increases bone remodeling by
osteoclastic resorption, which mobilizes calcium from
skeleton
PTH also increases renal tubular resorption of calcium &
renal products of active vitamin D metabolite

140. Types
Primary
Secondary
PRIMARY HYPERPARATHYROIDISM
Occurs due to benign tumour (adenoma) of one of four
parathyroid glands, which produces excess PTH
Diagnosis can be made on basis of hypercalcemia &
elevated serum PTH level

141. SECONDARY TYPE
Results from compensatory increase in output of PTH in
response to hypocalcemia
Hypocalcemia may be due to
Poor dietary intake
Poor absorption of Vitamin D
Deficient metabolism of Vitamin D in liver or kidney

142. RADIOGRAPHIC FEATURES OF JAWS
Demineralization & thinning of cortical boundaries often occur in the jaws in
cortical boundaries such as inferior borders, mandibular canal & the cortical
outlines of maxillary sinuses
The densities of the jaws is decreased, resulting in a radiolucent appearance
that contrasts with density of teeth

143. The teeth stand out in contrast to the radiolucent
jaws
A change in normal trabeculae pattern may occur,
resulting in ground- glass appearance of numerous
small, randomly oriented trabeculae

144. Brown tumour appear more frequently in facial bones
& jaws, particularly in long standing cases
Lesions may be multiple within a single bone
Have variably defined margins
May produce cortical expansion

145. RADIOGRAPHIC FEATURES OF
TEETH & ASSOCIATED
STRUCTURES
Lamina dura is lost (10%) giving
tooth a tapered appearance because of
decreased image contrast
It may occur around one tooth or all
teeth
It may be either partial or complete

146. REFERENCES
 Differential diagnosis of Oral & Maxillofacial lesions- 5th
Ed,Wood & Goaz
 Oral Radiology -5th Ed White & Pharoah-
 Diagnostic Imaging of Jaws- Langland, Langlais, Nortje
 Clinical Outline of Oral Pathology,Eversole
 Essentials of Dental Radiology & radiography,Eric
Whaites
 Textbook of Oral Pathology- 4th Ed ,Shafer, Hine, Levy