3 radio. anatomy.&interpert i

05/19/1605/19/16 OelshallOelshall 11
Dental RadiographicDental Radiographic anatomy
& interpretation
Part I
Dr. Ossama EL-Shall
Professor & Chairman, Faculty of DentalProfessor & Chairman, Faculty of Dental
Medicine for girls, Al-Azhar University,Medicine for girls, Al-Azhar University,
Cairo Egypt.Cairo Egypt.
E.mail address: oelshall@hotmail.comE.mail address: oelshall@hotmail.com

Dental radiographic
interpretation

Dental radiographic interpretationDental radiographic interpretation
Radiographic interpretation, is a
reading of a radiograph and
commenting on it to draw a diagnosis
Reading a radiograph includes
recording any deviation from the
normal appearance.

Rules of radiographic interpretationRules of radiographic interpretation
1-1- The area to be examined must be completelyThe area to be examined must be completely
shown at optimal angulationsshown at optimal angulations
2-2- All the boundaries of the area of interest must beAll the boundaries of the area of interest must be
shown with normal structures around it.shown with normal structures around it.
3-3- Knowing and familiarity with all normalKnowing and familiarity with all normal
anatomical landmarks as well as all variousanatomical landmarks as well as all various
pathological conditions that may affect the area ofpathological conditions that may affect the area of
interest.interest.

Principles of radiographicPrinciples of radiographic
interpretationinterpretation
Interpretation of a radiograph is not aInterpretation of a radiograph is not a
diagnosis by itself, but it is an diagnostic aiddiagnosis by itself, but it is an diagnostic aid
or mean help to reach a final diagnosis.or mean help to reach a final diagnosis.
Final diagnosis can be reached byFinal diagnosis can be reached by
performing a full case history, clinicalperforming a full case history, clinical
examination, special investigations andexamination, special investigations and
differential diagnosis.differential diagnosis.

Methods of interpretationMethods of interpretation
LLocalization.ocalization.
OObservation.bservation.
GGeneral consideration.eneral consideration.
IInterpretation.nterpretation.
CCorrelation.orrelation.

LocalizationLocalization
It is the identification and recognitionIt is the identification and recognition
of the area which the view shows, forof the area which the view shows, for
example: Upper anterior area, TMJexample: Upper anterior area, TMJ
area, Lower molar area………………..area, Lower molar area………………..

ObservationObservation
All shadows, other than the localizedAll shadows, other than the localized
shadows of the normal landmarks must beshadows of the normal landmarks must be
observed.observed.
For example: shadows in crowns, cervicalFor example: shadows in crowns, cervical
area, roots, restorations, size of rootarea, roots, restorations, size of root
canals, periodontal membrane space,canals, periodontal membrane space,
periapical area, alveolar crest, foreignperiapical area, alveolar crest, foreign
bodies, integrity of bone …………bodies, integrity of bone …………

General considerationGeneral consideration
A radiograph shows only 2 dimensions of a 3A radiograph shows only 2 dimensions of a 3
dimensional object (width and height but notdimensional object (width and height but not
the depth)the depth)
Cervical burnout: usually appears as cervicalCervical burnout: usually appears as cervical
RL and misinterpreted by caries; this occursRL and misinterpreted by caries; this occurs
due to less density and more penetration ofdue to less density and more penetration of
rays.rays.
Pulp exposure never to be determined fromPulp exposure never to be determined from
radiograph but only the proximity to the pulp.radiograph but only the proximity to the pulp.

InterpretationInterpretation
Studying the features ofStudying the features of teethteeth andand bonebone
TeethTeeth
Study the whole tooth, (crown, rootStudy the whole tooth, (crown, root
enamel, pulp….), number of teeth andenamel, pulp….), number of teeth and
finally supporting structures,finally supporting structures,
(Periodontal membrane space, lamina(Periodontal membrane space, lamina
dura, alveolar crest)dura, alveolar crest)

BoneBone
Changes in bone may include:Changes in bone may include:
1- Changes in density.1- Changes in density.
2- Changes in the margin2- Changes in the margin
3- Changes inside the lesion.3- Changes inside the lesion.
4- Effect on surrounding tissues.4- Effect on surrounding tissues.
5- Changes in structure5- Changes in structure

1- Changes in density.1- Changes in density.
Three bone density pattern may found:Three bone density pattern may found:
1-decrease in density resulting in RL1-decrease in density resulting in RL
2-Increase in density resulting in RO2-Increase in density resulting in RO
3- Combination of above.3- Combination of above.

2-Changes in the lesion margin2-Changes in the lesion margin
1- Well-defined margin with or without1- Well-defined margin with or without
sclerotic border denoting a slowlysclerotic border denoting a slowly
growing or chronic condition such asgrowing or chronic condition such as
cyst and granuloma.cyst and granuloma.
2- ill-defined margin, denoting acute2- ill-defined margin, denoting acute
active condition destroying bone in allactive condition destroying bone in all
directions, such as abscess, ordirections, such as abscess, or
malignancy.malignancy.

3- Changes inside the lesion.3- Changes inside the lesion.
1- Unilocular.1- Unilocular.
2-Multilocular.2-Multilocular.
3-Multiple and separate.3-Multiple and separate.

4-Effects on surrounding tissues.4-Effects on surrounding tissues.
1-May cause expansion, resorption,1-May cause expansion, resorption,
destruction or thinning of bone.destruction or thinning of bone.
2-Compressed adjacent tissues as max.2-Compressed adjacent tissues as max.
sinus or nasal cavitysinus or nasal cavity
3-Displacement of teeth, divergence or3-Displacement of teeth, divergence or
resorption.resorption.
4-Affection of lamina dura.4-Affection of lamina dura.

5- Changes in structure5- Changes in structure
1-Ground glass appearance; fine granules1-Ground glass appearance; fine granules
of bony trabeculation.of bony trabeculation.
2-Cotton wool appearance; irregular ill-2-Cotton wool appearance; irregular ill-
defined RO areas within area of moredefined RO areas within area of more
RLRL
3-Honeycomb; multilocular lesion with3-Honeycomb; multilocular lesion with
small compartments.small compartments.
4-Granular appearance: homogenous due4-Granular appearance: homogenous due
to loss of contrast between RL & ROto loss of contrast between RL & RO

CorrelationCorrelation
The final step is to correlate all ofThe final step is to correlate all of
the radiographic features to reach athe radiographic features to reach a
radiographic differential diagnosis.radiographic differential diagnosis.
Then to draw a final diagnosis, weThen to draw a final diagnosis, we
have to correlate other data as casehave to correlate other data as case
history, clinical examination, andhistory, clinical examination, and
other diagnostic aids with theother diagnostic aids with the
radiographic differential diagnosis.radiographic differential diagnosis.

Teeth and supporting tissues
Landmarks of maxilla
Landmarks of Mandible
Normal anatomical landmarksNormal anatomical landmarks

1- Enamel.
2- Dentin.
3- Cementum.
4- Pulp chamber and canal(s).
5- Tooth germ.
6- Periodontal ligament space.
7- Alveolar bone.
8- Lamina dura.
Teeth and supporting tissues.

Landmarks of maxilla.
Median palatine suture.Median palatine suture.
Nasal fossa.Nasal fossa.
Nasal septum.Nasal septum.
Anterior nasal spine.Anterior nasal spine.
Incisive foramen.Incisive foramen.
Lateral fossa.Lateral fossa.
Maxillary sinus.Maxillary sinus.
Malar bone.Malar bone.
Maxillary tubrosity.Maxillary tubrosity.
Hamular process.Hamular process.
Nasolacremal duct.Nasolacremal duct.

Landmarks of Mandible.Landmarks of Mandible.
Lingual foramenLingual foramen
Genial tubercles.Genial tubercles.
Mental ridge.Mental ridge.
Mental foramen.Mental foramen.
Mental fossa.Mental fossa.
External oblique line.External oblique line.
Internal oblique line.Internal oblique line.
Mylohyoid line or ridge.Mylohyoid line or ridge.
Mandibular foramen.Mandibular foramen.
Inferior dental canal.Inferior dental canal.
Submandibular gland fossa.Submandibular gland fossa.
Interdental nutrient canals.Interdental nutrient canals.
Pharyngeal space.Pharyngeal space.

Landmarks of maxilla.
Median palatine suture.Median palatine suture.
Nasal fossa.Nasal fossa.
Nasal septum.Nasal septum.
Anterior nasal spine.Anterior nasal spine.
Incisive foramen.Incisive foramen.
Lateral fossa.Lateral fossa.
Maxillary sinus.Maxillary sinus.
Malar bone.Malar bone.
Maxillary tubrosity.Maxillary tubrosity.
Hamular process.Hamular process.
Nasolacremal duct.Nasolacremal duct.

Maxillary anterior region
Nasal septum
Nasal fossa
Nasal spine
Incisive foramen
Nose
Median palatine suture

Median palatine suture
Appears as a vertically
oriented radiolucent line
in true image projections
through the midline.
Usually prominent
between the two central
incisor roots at young
individuals.

Median palatine sutureMedian palatine suture

Median palatal suture
palatal view

Nasal septum: (17)Appear as a
radio-opaque line separates
the two nasal fossa in the
midline.
Anterior nasal spine(16)
Appears as a v-shaped
radio-opaque structure in
the midline above the
incisive foramen.
Incisive foramen:(12) or the
anterior palatine fossa, it
usually appears as a
prominent radiolucent area
above/or between the roots
of two central incisors. It
usually appears as a
rounded or oval in shape not
exceeds 6mm in diameter.

Anterior nasal spineAnterior nasal spine
Nasal cavitiesNasal cavities Nasal septumNasal septum

e
f
a = nasal septum
b = inferior choncha
c = nasal fossa
d = anterior nasal spine
e = incisive foramen
f = median palatal
suture
a
d
c
facial view palatal view
b

Nasal septum
facial view

Nasal fossa
facial view

Incisive foramen
palatal view

Maxillary Canine region
Floor of nasal fossa
Maxillary sinus
Lateral fossa
Nose

a = floor of nasal fossa
b = maxillary sinus
c = lateral fossa
(a & b form inverted Y)
a
c
b
a
c
b
facial view

Floor of nasal fossa (red arrows) and anterior border
of maxillary sinus (blue arrows), forming the inverted
(upside down) Y.Y
facial view

The maxillary sinus
surrounds the root of the
canine, which may be
misinterpreted as
pathology.
The white arrows indicate
the floor of the nasal fossa.
The maxillary sinus (red
arrows) has pneumatized
between the 2nd
premolar and
first molar

Zygomatic
process
Sinus septum
Maxillary sinus
Maxillary Premolar region

a = malar process
c = sinus septum
d = maxillary sinus
a c d dca
facial view

5-Maxillary sinus:5-Maxillary sinus:
The maxillary sinus withThe maxillary sinus with
its thin bony walls, itsits thin bony walls, its
thin mucosa, and its vastthin mucosa, and its vast
air space, produce anair space, produce an
extremely dark imageextremely dark image
(10)(10) deep to the maxillarydeep to the maxillary
teeth.teeth.
Its outlines, particularly itsIts outlines, particularly its
floor, are clearlyfloor, are clearly
delineated by delicatedelineated by delicate
radiopaque linesradiopaque lines (11).(11).

1-Body of zygoma1-Body of zygoma
6-Apices of roots6-Apices of roots
7-floor of the sinus7-floor of the sinus
8-Septum of the sinus8-Septum of the sinus
Notice the well-demarcated RL area related to 5 toothNotice the well-demarcated RL area related to 5 tooth

In general the floor of theIn general the floor of the
sinus is approximatelysinus is approximately
coincidental with thecoincidental with the
location of the apices oflocation of the apices of
the roots of the upperthe roots of the upper
teeth,(bicuspids and firstteeth,(bicuspids and first
two molars).two molars).
But there is often as muchBut there is often as much
as 2 or even 3 millimetersas 2 or even 3 millimeters
of maxillary boneof maxillary bone
between the root ends andbetween the root ends and
sinus floor.sinus floor.

In other cases the sinus floor dips so deeplyIn other cases the sinus floor dips so deeply
between the roots of the maxillary teeth thatbetween the roots of the maxillary teeth that
the latter appear to project into it for as muchthe latter appear to project into it for as much
as one half of their length.as one half of their length.

Pneumatization. Expansion of sinus wall into
surrounding bone, usually in areas where
teeth have been lost prematurely.
Increases with age.

Malar bone:
Or the zygomatic process.
The inferior portion of the
malar bone appears as a
Radiopaque u-shaped
structure related to the
roots of the first maxillary
molar.
It represents the attachment
of the zygomatic bone to the
maxilla.

Malar (zygomatic) process. U or j-shaped
radiopacity, often superimposed over the roots
of the molars, especially when using the
bisecting-angle technique. The red arrows define
the lower border of the zygomatic bone.
facial view

Malar bone Maxillary sinus

Maxillary Molar Region
Maxillary sinusZygoma
Pterygoid plate
Hamular
process
Coronoid process Maxillary tuberosity

g
d
a
e
f
a = maxillary tuberosity* e = zygoma (dotted lines)
b = coronoid process f = maxillary sinus
c = hamular process g = sinus recess
d = pterygoid plates
* image of impacted third molar superimposed
c
facial view
d
b
a
e
c f
g

Maxillary Tuberosity:
Appears as a Radiopaque structure that
extends distally and upward from
posterior to maxillary sinus. It represents
the end of maxilla.

Maxillary Tuberosity. The rounded elevation
located at the posterior aspect of both sides
of the maxilla. Aids in the retention of
dentures.
facial view

Coronoid process of the mandible:
Appears as a triangular Radiopaque
structure projected into the same general
area of maxillary Periapical film projections
distally to the maxillary teeth.

Coronoid process. A mandibular structure sometimes
seen on the maxillary molar periapical film when using
the bisecting angle technique with finger retention
(The mouth is opened wide, moving the coronoid down
and forward). Note the supernumerary molar.
facial view

Hamular process:
It is a bony spine (5) projecting from the
pterygoid process of the sphenoid bone. It
appears as a Radiopaque spine that recorded
on radiographs distal to the tuberosity of the
maxilla and extends downward.

Hamular process (blue arrows) and pterygoid plates
(purple arrows). The hamular process is an
extension of the medial pterygoid plate of the
sphenoid bone, positioned just posterior to the
maxillary tuberosity.
facial view

The zygomatic process (green arrows) is a prominent
U-shaped rationality. Normally the zygomatic bone
posterior to this is very dense and Radiopaque. In this
patient, however, the maxillary sinus has expanded into
the zygomatic bone and makes the area more radiolucent
(red arrows). The coronoid process (orange arrow), the
pterygoid plates (blue arrows) and the maxillary
tuberosity (pink arrows) are also identified.

Lingual foramenLingual foramen
Genial tubercles.Genial tubercles.
Mental ridge.Mental ridge.
Mental foramen.Mental foramen.
Mental fossa.Mental fossa.
External oblique line.External oblique line.
Internal oblique line.Internal oblique line.
Mylohyoid line or ridge.Mylohyoid line or ridge.
Mandibular foramen.Mandibular foramen.
Inferior dental canal.Inferior dental canal.
Submandibular gland fossa.Submandibular gland fossa.
Interdental nutrient canals.Interdental nutrient canals.
Pharyngeal space.Pharyngeal space.

Mandibular Incisors region
Mental ridge
Genial tubercles Lingual foramen
Mental fossa

Lingual foramen:
It set in the midline
deep to the root apices
of the anterior teeth.
It appears as a small
radiolucent dot at the
symphysis area. It
usually surrounded with
a Radiopaque structure.

Lingual foramen. Radiolucent “hole” in center
of genial tubercles. Lingual nutrient vessels
pass through this foramen.
lingual view

Genial Tubercles: Or the
superior and inferior mental
spines.
They are four in number located
toward the inferiolingual
border of the mandible and are
mostly 2 on each side of the
midline, although in some
instances they coalesce as a
single radiopaque outcrop of
the mandible.
They appear as a radiopaque
circle that surrounds the
lingual foramen, just below the
apices of the incisors.
Anatomically genyoglossal muscle
attached to the superior two
while the genyohyoid muscle
attached to the inferior two.

Genial tubercles. Radiopaque area in the midline,
midway between the inferior border of the mandible and
the apices of the incisors. Serve as attachments for the
genioglossus and geniohyoid muscles. May have
radiolucent hole in center (lingual foramen), but not on
this film. Note double rooted canine (red arrows).
lingual view

Mental ridge:Mental ridge: It is a bony prominence found on the labialIt is a bony prominence found on the labial
aspect of the mandible near its inferior border and extendedaspect of the mandible near its inferior border and extended
from the premolar region to the symphysis area on which itfrom the premolar region to the symphysis area on which it
takes an upward turn as it approach it. It appears as atakes an upward turn as it approach it. It appears as a
radiopaque line below the apices of anterior teeth.radiopaque line below the apices of anterior teeth.

Mental ridge.
facial view

Mental Fossa (6):Mental Fossa (6):
It is a slight depressionIt is a slight depression
in the bone one thein the bone one the
labial aspect of thelabial aspect of the
mandible. It appearsmandible. It appears
as a faint radiolucentas a faint radiolucent
structure related tostructure related to
anterior area.anterior area. Notice: 7 is cervical burnout

b = genial tubercles
a = lingual foramen c = mental ridge
d = mental fossa
a
b
cd
facial viewlingual view

Mental fossa. This represents a depression on the
labial aspect of the mandible overlying the roots of
the incisors. The resulting radiolucency may be
mistaken for pathology.
facial view

Mandibular Premolar region
a = mylohyoid ridge
b = mandibular canal
c = submandibular gland fossa
d = mental foramen

Mental foramen(3)Mental foramen(3)
It appearsIt appears
as a radiolucent ill-as a radiolucent ill-
defined area betweendefined area between
the apices of thethe apices of the
bicuspids. Itbicuspids. It
represent the anteriorrepresent the anterior
terminates of theterminates of the
mandibular canal.mandibular canal.

c
b = mandibular canal
d = mental foramen
a = mylohyoid ridge
(internal oblique)
c = submandibular gland
fossa
facial view lingual view
c
a
dd b

Mental foramen. Usually located midway between
the upper and lower borders of the body of the
mandible, in the area of the premolars. May
mimic pathology if superimposed over the apex
of one of the premolars.
facial view

Mandibular Molar region
a = external oblique ridge
b = mylohyoid ridge
c = mandibular canal
d = submandibular gland fossa

facial view lingual view
b
c
a
b
b = mylohyoid ridge
d = submandibular gland
fossa
dd

External oblique line:(6)
It is a Radiopaque line
extending from anterior
border of the ramus of
the mandible and
descends to the third
molar area.
7-Internal oblique line,
7-Mylohyoid line,
9-Mandibular canal,

External oblique ridge. A continuation of the
anterior border of the ramus, passing downward and
forward on the buccal side of the mandible. It
appears as a radiopaque line which usually ends
anteriorly in the area of the first molar. Serves as
an attachment of the buccinator muscle. (The red
arrows point to the mylohyoid ridge).
facial view

Internal oblique line(6):
It appears as a Radiopaque
line descends downward
and forward from
Coronoid process; in a
more horizontal position;
stop at the third molar area
or become continuous with
the Mylohyoid line. Its
place below the external
oblique line.

Mylohyoid line or ridge(7)
It is a Radiopaque line
below the external oblique
line and it is the anterior
continuity of the internal
oblique line.
It extend downward and
forward from the ramus
of the mandible to the
bicuspid areas.

Mylohyoid ridge (internal oblique). Located on
the lingual surface of the mandible, extending
from the third molar area to the premolar region.
Serves as the attachment of the mylohyoid
muscle.
lingual view

Inferior dental canal; (9,2),
Mandibular canal, or
inferior alveolar canal.
Its characteristic image is
therefore likely to be a
radiolucent passage along
the mandible just deep to
the roots of the teeth,
terminating at the mental
foramen and bounded by
Radiopaque margins
representing the walls of
thin cortical bone bounding
the canal.

facial view
Mandibular (inferior alveolar) canal. Arises at the
mandibular foramen on the lingual side of the ramus and
passes downward and forward, moving from the lingual
side of the mandible in the third molar region to the
buccal side of the mandible in the premolar region.
Contains the inferior alveolar nerve and vessels.

Submandibular gland
fossa(4):
It is a depression on
the lingual aspect of the
mandible on which
submandibular glands
are present.
It appears as a zone of
radiolucency below the
lower molars.

lingual view
Submandibular gland fossa. A depression on
the lingual side of the mandible below the
mylohyoid ridge. The submandibular gland is
located in this region. Due to the thinness of
bone, the area being very radiolucent. The fact
that it occurs bilaterally helps to differentiate it
from pathology.

ab
c
dd
b = mylohyoid ridge
d = submandibular gland fossa

The external oblique ridge (red arrows) and
the mylohyoid ridge (blue arrows) usually run
parallel with each other, with the external
oblique ridge always being higher on the film.

The mandibular canal (red arrows identify inferior border
of canal) usually runs very close to the roots of the
molars. Note the extreme dilaceration of the roots of
the third molar (green arrow).
The film at right shows “kissing” impactions located at
the superior border of the canal.

as seen in occlusal filmsas seen in occlusal films

Nasolacrimal duct:
It almost seen in
occlusal view of the
maxilla as a round
radiolucent area
superimposed on the
posterior region of the
hard palate.

as seen in panoramic viewsas seen in panoramic views

Misinterpretation of normalMisinterpretation of normal
radiographic anatomicalradiographic anatomical
landmarks with pathologicallandmarks with pathological
lesionslesions

Median palatine sutureMedian palatine suture
A Median palatine suture:
-Can misinterpreted for a
fracture line
-To differentiate between them:
-Suture is regular and is
surrounded by 2 radio- opaque
lines
-While Fracture line is irregular
and is just a radiolucent line
without definite borders.

Fracture line Median suture

Incisive foramen & Mental foramenIncisive foramen & Mental foramen
Both can be misinterpreted for a periapicalBoth can be misinterpreted for a periapical
granuloma or any other periapical pathosis.granuloma or any other periapical pathosis.

To differentiate
1- Check the continuity of
lamina dura.
2- Shift technique.
3- Vitality test.
4- Concerning mental
foramen, check the
evidence of continuity
with alveolar canal.

Periapical lesionPeriapical lesion Mental foramenMental foramen

Maxillary sinusMaxillary sinus
Can be misinterpreted for a cystCan be misinterpreted for a cyst
To differentiate:To differentiate:
Check the normal radiographic appearanceCheck the normal radiographic appearance
of the sinus with its septae.of the sinus with its septae.
Take a radiograph of the other sinus toTake a radiograph of the other sinus to
compare.compare.
The radiolucency of the sinus (air filled) isThe radiolucency of the sinus (air filled) is
more than that of cyst (fluid filled)more than that of cyst (fluid filled)
Vitality test.Vitality test.

Max. sinus
cyst
cyst
sinus
sinus

The Coronoid processThe Coronoid process
When it superimposed on the maxillaryWhen it superimposed on the maxillary
tubrosity, it can misinterpreted as impactedtubrosity, it can misinterpreted as impacted
tooth.tooth.
To differentiate: shifting tech.To differentiate: shifting tech.

Which is a depression on the labial aspectWhich is a depression on the labial aspect
of the mandible above the mentalof the mandible above the mental
protuberance.protuberance.
It can misinterpreted for a PeriapicalIt can misinterpreted for a Periapical
lesion affecting lower incisors.lesion affecting lower incisors.
It can differentiate by shifting tech. orIt can differentiate by shifting tech. or
vitality test.vitality test.
The mental fossaThe mental fossa

3 radio. anatomy.&amp;interpert i

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