Intraoral periapical
anatomical landmarks
Maxillary Incisor
a
b a = nasal septum
c b = inferior concha
c = nasal fossa
d d = anterior nasal spine
e e = incisive foramen
f = median palatal suture
g = soft tissue of nose
f
g
facial view palatal view
c f
b
a e
d
a = nasal septum e = incisive foramen
b = inferior concha f = median palatal
c = nasal fossa suture
d = anterior nasal spine
facial view
Nasal septum
facial view
Inferior concha
facial view
Nasal fossa
facial view
Anterior nasal spine
palatal view
Incisive foramen
palatal view
Median palatal suture
Soft tissue of the nose
a
a
b b
d
e
Red arrow points to Red arrows = lip line
periapical lesion
(post-endo).
The red arrows point to the soft tissue of the nose.
The green arrows identify the lip line.
Maxillary Cuspid
a
a =lateral wall of nasal fossa
b
b = anterior wall of
c maxillary sinus
c = lateral fossa
d = nose
d
facial view
a a
c c
b
b
a = floor of nasal fossa
b = maxillary sinus
c = lateral fossa
(a & b form inverted Y)
facial view
Floor of nasal fossa (red arrows) and
anterior border of maxillary sinus (blue
arrows), forming the inverted (upside
facial view
Lateral fossa. The radiolucency results from a
depression above and posterior to the lateral
incisor. To help rule out pathology, look for an
intact lamina dura surrounding the adjacent teeth.
Soft tissue of the nose
Red arrows point to nasolabial fold.
Also note the inverted Y.
The maxillary sinus The white arrows indicate the
surrounds the root of the floor of the nasal fossa. The
canine, which may be maxillary sinus (red arrows)
misinterpreted as has pneumatized between the
pathology. 2nd premolar and first molar
Nasolacrimal canal
Maxillary Premolar
a b
a = malar process
b = sinus septum
c = maxillary sinus
c
facial view
c
a c a c c
a = malar process
c = sinus septum
c = maxillary sinus
facial view
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
Sinus septum. This septum is composed
of folds of cortical bone that arise from the
floor and walls of the maxillary sinus,
extending several millimeters into the
sinus. In rare cases, the septum
completely divides the sinus into separate
compartments.
facial view
Maxillary Sinus. An air-filled cavity lined with
mucous membrane. Communicates with nasal
cavity through 3-6 mm opening below middle
concha.
The red arrows point to
the nasolabial fold. The
thicker cheek tissue
makes the area more
radiopaque posterior to
the line.
Pneumatization. Expansion of sinus wall into
surrounding bone, usually in areas where
teeth have been lost prematurely. Increases
with age.
Maxillary Molar
a = maxillary tuberosity d e
b = coronoid process
c = hamular process
d = zygoma c
e = maxillary sinus b
a
facial view
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. 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 (white arrows)
facial view
Zygomatic (malar) bone/process/arch. The
zygomatic bone (white/black arrows) starts
in the anterior aspect with the zygomatic
process (blue arrow), which has a U-shape.
The zygomatic bone extends posteriorly
into the zygomatic arch (green arrow).
facial view
Maxillary sinus. As seen in the above film, the floor of the
maxillary sinus flows around the roots of the maxillary molars
and premolars. The walls of the sinus may become very thin.
As a result, sinusitis may put pressure on the superior
alveolar nerves resulting in apparent tooth pain, even though
the tooth is perfectly healthy. Note coronoid process (green
arrow), zygomatic bone (blue arrow), sinus septum (yellow
arrow).
The zygomatic process (green arrows) is a
prominent U-shaped radiopacity. 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.
This film shows the expansion of the borders of the
maxillary sinus through pneumatization (red arrows).
This expansion increases with age and it may be
accelerated as a result of chronic sinus infections. It
is most commonly seen when the first molar is
extracted prematurely, as in the film at right (the
second and third molars have migrated anteriorly to
close the space). The coronoid process is seen in the
lower left-hand corner of each film. Note the two
distomolars in film at right (blue arrows).
Hard palate
Zygomatic process of
maxilla
Mandibular Incisor
a. lingual foramen
b. genial tubercles
c. mental ridge
d. mental fossa
a b c
lingual view
Lingual foramen. Radiolucent “hole” in center of
genial tubercles. Lingual nutrient vessels pass
through this foramen.
facial view
Mental ridge. These represent the raised portions of the
mental protuberance on either side of the midline. More
commonly seen when using the bisecting angle technique,
when the x-ray beam is directed at an upward angle
through the ridges.
facial 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.
The radiolucent area above corresponds to The orange arrows above identify
the location of the mental fossa. However, nutrient canals. They are most often
this slide represents chronic periapical seen in older persons with thin bone,
periodontitis; these teeth are non-vital, due
and in those with high blood pressure
to trauma.
or advanced periodontitis.
Nutrient canals
Mandibular Canine
a = mental ridge
c b = genial tubercles/
lingual foramen
c = mental foramen
b
a
facial view lingual view
db22
b
d
a
d
c
b1
d
a = mental ridge b1 = genial tubercles
c = mental foramen b2 = lingual foramen
facial view
Mental ridge. The raised portions of the mental protuberance,
sloping downward and backward from the midline.
lingual view
Lingual foramen/genial tubercles. (See
description under mandibular incisor
above).
facial view
The red arrows identify the mandibular canal and
the blue arrow points to the mental foramen.
Mandibular Premolar
a = mylohyoid ridge
b = mandibular canal
c = submandibular gland fossa
d = mental foramen
facial view lingual view
b a
d
b = mandibular canal a = mylohyoid ridge
d = mental foramen (internal oblique)
c = submandibular gland
fossa
lingual view
Mylohyoid (internal oblique) ridge. This radiopaque
ridge is the attachment for the mylohyoid muscle.
The ridge runs downward and forward from the
third molar region to the area of the premolars.
facial view
Mandibular canal. (Inferior alveolar canal). Runs
downward from the mandibular foramen to the
mental foramen, passing close to the roots of the
molars. More easily seen in the molar periapical.
lingual view
Submandibular gland fossa. The depression below
the mylohyoid ridge where the submandibular gland
is located. More obvious in the molar periapical film.
facial view
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.
To differentiate mental foramen from periapical lesion:
1. Lamina durra; if it intact……mental foramen, if not intact go
to
2. Shift technique; lesion remains attached to the root while
normal anatomy location changes with changing
radiographic angle.
Mandibular Molar
a = external oblique ridge
b = mylohyoid ridge
c = mandibular canal
d = submandibular gland fossa
facial view lingual view
a
b
c d
a = external oblique ridge b = mylohyoid ridge
c = mandibular canal d = submandibular gland
fossa
b a
d
c
a = external oblique ridge
b = mylohyoid ridge
c = mandibular canal
d = submandibular gland fossa
facial view
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 distinct
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).
lingual view
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
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 trabecular
pattern of the bone is very sparse and results in
the area being very radiolucent. The fact that it
occurs bilaterally helps to differentiate it from
pathology.
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, especially the third molar. This can be a problem
when extracting these teeth. Note the extreme
dilaceration (curving) of the roots of the third molar (green
arrow) in the film at left. The film at right shows “kissing”
impactions located at the superior border of the canal.
Nutrient canals (arrows), demonstrated by radiopaque
cortical borders, descend from the mandibular first
molar. Nutrient canals at this location are a common
finding
The alveolar crests (arrows) are seen as
cortical borders of the alveolar bone. The
alveolar crest is continuous with the lamina
dura.
Teeth are composed of pulp (arrow on the second
molar), enamel (arrow on the first molar), dentin (arrow
on the second premolar), and cementum(usually
not visible radiographically).
The lamina dura (arrows) appear as a thin opaque layer of
bone around teeth (A) and around a recent extraction socket
(B) persists after extraction up to 6 months.
•Blue arrows pointing at dental papilla
Green arrow: Tooth crypt of developing
second premolar
Blue arrow: Dental papilla (funnel shape
opening of the incomplete root).
Upper vs. Lower radiographs
Normal teeth morphology
Normal anatomical landmarks
Bone anatomy maxilla vs. mandible
Identify the anatomical structures
on the following eight slides. The
answers are on the last slide.
Slide # 1
A. The red arrows identify the ?
Slide # 2
A. The red arrow points to the ?
B. The white arrows identify the ?
C. The blue arrow points to the ?
D. The yellow arrow identifies the ?
Slide # 3
A. The small radioluceny identified by
the green arrow is the ?
Slide # 4
A. The radiopacity identified by the
blue arrows is the ?
B. The orange arrow identifies the ?
Slide # 5
A. The yellow arrows point to the ?
B. The red arrows identify the ?
Slide # 6
A. The red arrow points to the ?
B. The orange arrow points to the ?
C. The blue arrows point to the
radiolucent line known as the ?
Slide # 7
A. The red arrows point to the ?
Slide # 8
A. The red arrows identify the ?
B. What is the name of the radiolucent
area surrounding the canal?
