this presentation gives you an outline background about Anatomical landmarks in Periapical and Orthopantomogram X-ray in dental field..

1. Anatomical landmarks
in
PA and OPG
Rizgar S.
Ishık University School of Dentistry
Diagnostic Department
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2. Anatomical landmarks
in PA
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3. • Introduction:
• Periapical radiograph is a type of Intra oral
view in which the film is placed inside
patient’s mouth and radio graphed using
various techniques. . (Bisected angle,
paralleling. .)
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4. • The interpretation of radiographs plays an
important role in the dental office. Several
abnormalities are diagnosed solely by or with
help of radiographs. For this reason the
training in the interpretation of dental
radiographs plays an import-ant role in the
curriculum of dental students and hygienists.
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5. Peiapical Films Show:
• Teeth
• Dental Germ
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6. • Tooth Consists of:
– Enamel(RO)
– Dentine(RO but less than enamel)
– Cementum(RO & Similar density to dentine)
– Pulp chamber & root Canals (RL)
RO=Radio opaque
RL=Radiolucent
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7. Investing Structures Are:
 Cancellous Bone (Mixed RO & RL)
 Lamina Dura (RO) . . Normally it appears
surrounding and parallel to root of tooth as RO
line . . Periodontal Membrane Space Is The RL
between Then . . It Should Be Of Uniform
Thickness Normally
 Cortical Crest (RO) . . .Anteriorly It In Knife Edge
Appearance
Posteriorly . . Flattened
RO=Radio opaque RL=Radiolucent
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8. Normal Maxillary Anatomical
Landmarks:
1-Anterior Region:
• Radolucent Structures:
Nasal Fossa
W Shaped Radiolucency . .
. May Be MisInterpretated As Soft Tissue Tumor . . .
To Make Sure It Is Nasal Fossa use Shift Skitch Technique
If Lesion Persists In Place : It Is Pathosis
If Changes its Position: It Is Nasal Fossa
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9. Incisive Foramen:
It is the opening in the midline of the
palate just posterior to the central
incisors. it gives passage to the
nasopalatine artery and nerve .
It should not be misdiagnosed As
Dental Infection Or Cyst.
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10. Median Palatine Suture:
• is the line down the center of the maxilla
where embryonic palatal shelves joined at
the midline to form the hard palate.It
Should Not be misdiagnosed As fracture
line nor fistulous tract . . .
• To diffrentiate . . .
• Fracture line will be acoompaigned by
history of trauma, it will be irregular RL
Line, Will not be bordered By 2 RO Lines . .
.
• Fistulous tract: by applying RO material
through the lesion . . . the tortuous course
of the tract can be observed 10

11. Incisive Fossa:
• Also Called Canine Fossa . . And It Is the
indentation between the roots of the
central and lateral incisors, and the
canine fossa is between the roots of the
lateral incisor and canine.
• It should not be Misdiagnosed As
pathological condition. . If So
Radiograph the other side for
comparison. .
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12. • Nasopalatine Canals:
If Exaggerated vertical Angle is used
they may appear as projections of
maxillary Incisors . . .
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13. Rdiopaque Structures:
Median Nasal Septum:
It is the thin wall of bone in the midline of
the face that separates the right and
left nasal fossae. . In Some cases
unusual density may denote
supernumerary tooth, mesiodens, or a
retained root . . .
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14. • Anterior Nasal Spine:
It is the triangular protuberance of bone that
extends forward from the inferior aspect
of the nasal cavity at the midline. . .
It Should Not Be MisInterpretated As
remaining root, Odon tome , Impaction,
Foreign Body . . .
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15. Nasal Turbinates:
Cartilaginous radiopacity that may
appear on anterior maxillary
radiographs is the inferior conch or
inferior nasal turbinate. There are
actually three turbinates on each side
of the nasal antrum; however, only
the most inferior of these is routinely
projected onto the periapical view of
the incisor region.
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16. Nasal Cartilage:
It is the soft tissue of the tip
of the nose. .It Appears as
RO Shadow superimposed
over incisors’ Roots . . It Is
Uniform Opacity With
Sharp Borders. .
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18. 18

19. 19

20. Rdiopaque Structures:
Malar Bone:
It Is where Zeugmatic Bone Attach To Maxilla …
It Appears As Well Defined RO Area super
Imposed over Maxillary Molar Roots. .
So Interpretation of this view is difficult . . .
But effort may be exerted and different angulations
may be used to shift this zygomatic shadow. .
It may be misdiagnosed as impacted teeth or
foreign bodies
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21. 4-Regions Posterior To Upper Third
Molar
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23. 23

24. Normal Mandibular Anatomical
Landmarks:
Radiopacities
1. Genial Tubercles
The genial tubercles are small bony spines
found on the lingual aspect of the
mandible adjacent to the midline at the
attachment of the geniohyoid and
genioglossus muscles.
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25. • 2)-MENTAL RIDGE:
The mental ridges are elevated
ridges of bone located along
the anterior aspect of the
mandible. The ridges are also
known as the mental tubercles
and fuse at the mid-line to
form the mental protuberance,
the anterior most aspect of the
mandible. This periapical
radiograph demonstrates the
radiopaque margin of the
mental ridges. Study these and
compare the varying
appearance of these
landmarks.
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26. • 3)-Lingual Foramen:
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27. 4)-Interdental Nutrient
Canals:
They Contain Blood Vessels And
Nerves That Supply teeth And
Investing Structures . . They
Appear as RL Lines of uniform
width and sometimes exhibit
RO margins . . .they are clearly
seen In Patients with
edentulous Mouth. .
They Should Not Be
MisInterpretated As Fracture
Lines . .If so They will be
irregular lines with previous
history of trauma . . 27

28. 2-Premolar Region:
The Most Important
Structure In This Area
Is Mental foramen.
• The best way to differentiate
periapical disease from the
mental foramen is to identify the
periodontal membrane space to
see if it is confluent with the
radiolucent opening.
Periapical lesion - Mental foramenMental foramen - Periapical lesion
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29. 3-Molar Region:
Mandibular Canal:
The inferior alveolar nerve and
artery pass through the
mandible through a structure
called the mandibular canal.
The mandibular canal extends
from the mandibular foramen,
on the lingual aspect of the
ramus, through the body of the
mandible under the roots of
the molar teeth.
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30. • SubMandibular Fossa:
Directly below the internal
oblique ridge is a depression
in the lingual aspect of the
mandible called the
submandibular fossa.
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31. Lower Border Of Mandible:
The lower border of the
mandible is the thick cortical
plate that forms the lower
edge of the mandible. The
solid thickness of bone along
the inferior border of the
mandible is seen in the
radiograph as a uniform wide
radiopaque band at the
margin of the mandible.
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32. Intra Orally:
The internal oblique ridge (or mylohyoid line) is an
eminence of bone extending along the lingual
aspect of the mandible. It serves as the
attachment point for the chief muscle of the
mouth floor, the mylohyoid muscle.
This drawing shows the location and direction
of mylohyoid muscle, which is attached to the
mandible at the internal oblique ridges.
Radiographically the internal oblique ridge
appears as a radiopaque band extending from
the terminal molar region to the premolar
area, as seen in this periapical projection. Note
that part of the mandibular canal is visible just
below the mylohyoid line and is often
superimposed on the image of the internal
oblique ridge.
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33. Extra Orally:
• The external oblique ridge is a ridge of bone
located along the facial of the mandible, which
extends from the superior aspect of the
posterior body of the mandible down to the
necks of the molar teeth. It runs in the same
direction as the internal oblique ridge, but is
located on the facial, or external surface of the
mandible. The external oblique ridge serves as
the attachment point for the buccinator muscle,
as demonstrated in this drawing. The next two
periapical projections demonstrate the
radiographic appearance of the external oblique
ridge. To distinguish radiographically between
the internal and external oblique ridges, note
that the external ridge is always superior to the
internal oblique ridge. In this image the external
oblique ridge is denoted by white arrows while
the internal oblique ridge is demarcated by black
arrows.
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34. Anatomical landmarks
in OPG -Orthopantomograph-
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35. Panoramic radiograph:
is a panoramic scanning dental X-ray of upper
and lower jaw. It shows a two-dementional
view of half-circle from ear to ear.
Abbrevuiatoins used are:
PAN, OPT, DPR and OPG..
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36. Indications:
OPG is used to provide information about:
 Diagnosis and treatment planning of impacted wisdom teeth.
 diagnosis of developmental anomalies like cherubsim, cleido cranial
dysplasia
 Carcinoma in relation to the jaws.
 Periodontal bone loss plus periapical involvement.
 finding source of pain.
 assessment of for the placement of dental implants.
 orthodontic assessment
 Diagnosis of osteosarcoma, ameloblastoma, renal ostiodystrophy and
hypophoaphatemia.
 dentoalviolar fractures
 salivary stone
 TMJ problems and ankylosis.. 36

37. Projection of OPG
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38. Anatomical landmarks
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40. Soft tissues on OPG
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42. Thanks 42