intraoral radiographic anatomy

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It’s time for… Intraoral Radiographic Anatomy

Steven R. Singer, [email protected]

“Alas, poor Yorick!”

Radiographic Contrast

The difference in densities between adjacent areas of the imageInfluenced by:! Subject contrast! Film contrast! Beam energy and intensity! Fog and scatter radiation



By adjusting kVp, contrast can be varied! High contrast films can enhance

detection of lesions where subject contrast between the lesion and healthy tissue is low

! Examples include:" Caries" Apical lucencies


By adjusting kVp, contrast can be varied! Low contrast films can enhance

detection of subtle findings.! Examples include:

" Calculus" Soft tissue outlines" Small changes in crestal bone

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Radiographic Density

The overall degree of darkening of the radiographic image. Three factors which determine radiographic density are:! Exposure! Subject thickness! Object density


Exposure! Determines the # of photons that are

absorbed by the emulsion! Four exposure factors

" kVp" ma" Impulses (time)" Source to film distance


Subject thickness


Object Density. The denser the object and higher the atomic #, the better the absorption of photons.


In decreasing order of density:! Metallic restorations! Enamel! Dentin! Bone! Fat/fluid! Air

Subject Contrast

Influenced by:ThicknessDensityAtomic #

Relatively differences in Subject Contrast of oral structures allow the image to be seen

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Subject Contrast Definitions

Radiodensity: The degree to which the subject attenuates the x-ray beamRadiopacity: An area of the image where the beam has been relativelyhighly attenuatedRadiolucency: An area of the image where the beam has been relatively minimally attenuated

Radiolucencies

Marrow spacesForaminaCanals (N.B. the walls of the canal are opaque)Fissures

Fossae MeatiSinusesSuturesDental pulp

Radiopacities

BoneCondylesEminencesProcessesTuberositiesWalls of canalsTuberclesRidgesTrabeculae

TeethEnamelDentinCementum

The Teeth

Enamel 90% mineralizedDentin 75% mineralizedCementum 50% mineralizedPulp Soft tissue

The Teeth

EnamelDentinPulp

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The Teeth

Cervical burnout

The Teeth

Concavities

The Teeth

Fluting of root surfaces

Supporting Structures of the Teeth

Trabecular bone

Bone in the Anterior Maxilla

Trabeculae are thin and numerousSmall marrow spaces

Bone in the Posterior Maxilla

Similar pattern to anterior maxillaSlightly larger marrow spaces

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Bone in the Anterior Mandible

Trabeculae are somewhat thicker than in the maxillaPlates are in a horizontal pattern

Bone in the Posterior Mandible

Horizontal PlatesLarger marrow spaces than anterior mandible



Crestal bone


Lamina duraPeriodontalligament space


The joint between the tooth and the bone is a gomphosis. The periodontal ligament allows for movement around a center of rotation.

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Lamina dura and PDL

Landmarks

Landmarks in the Maxilla

Intermaxillary sutureNasal FossaNoseLateral fossa

e

f

a = nasal septumb = inferior conchac = nasal fossad = anterior nasal spine

e = incisive foramenf = median palatal

suture

ba

d

c

facial view palatal view

e

f


Incisive foramenMedian palatine suturePterygoid plates

Pterodactyl gr. pteron, wing

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Anterior nasal spineZygomatic processPterygoid platesCoronoid process of the mandibleNasolabial fold

Coronoid Process

From the Greek word for “Crow’s Beak”


Latyeral pterygoid platePterygo-maxillary fissureZygomatico-temporal sutureZygomatic process of the maxilla

Maxillary Incisor

a = nasal septumb = inferior conchac = nasal fossad = anterior nasal spinee = incisive foramenf = intermaxillary sutureg = soft tissue of nose

b

a

g

f

edc

Nasal fossa

facial view


Intermaxillary sutureSoft tissue of the noseIncisive foramen

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Soft tissue of the nose


The red arrows point to the soft tissue of the nose. The green arrows identify the lip line.


Foramina of von Ebner


Nasopalatine canal


Incisive foramen


Incisive foramen

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Anterior nasal spine


a = floor of nasal fossa

b = maxillary sinus

c = lateral fossad = soft tissue of the nose

Maxillary Canine

d

c

b

a

Lateral fossa. The radiolucency results from a depression above and posterior to the lateral incisor. To help rule out pathoses, look for an intact lamina dura surrounding the adjacent teeth.

facial view


Lateral fossa


Nasal Fossaa = zygomatic process of maxillab = sinus septumc = sinus recessd = floor of the maxillary sinuse = maxillary sinus

a b c

e

Maxillary Premolar

d

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a = zygomatic process of maxillab = sinus septumc = sinus recessd = floor of the maxillary sinuse = maxillary sinus

a b c

e

Maxillary Premolar

d

a = zygomatic processb = sinus recessc = sinus septumd = floor of the maxillary sinus

b

a c db

dca

facial view


Nasolabial fold

Maxillary Molar

a = maxillary tuberosity

b = coronoid process

c = hamular process

d = pterygoid plates

e = zygoma

f = maxillary sinus

fe

dcb

a


Zygomatic Process and Maxillary Sinus


Zygomatic Process and Maxillary Sinus

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Pneumatization. From the Latin “filled with air” Expansion of sinus wall into surrounding bone, usually in areas where teeth have been lost prematurely. Increases with age.

Mucositis Halo effect


Maxillary tuberosityCoronoid process of the mandibleHamular process

Tuberosity

Hamularprocess

Coronoid Process


Hamular process

Hamularprocess

Tuberosity

Maxillary Tuberosity. The rounded elevation located at the posterior aspect of both sides of the maxilla.

facial view

Landmarks in the Mandible

Mental ridgesMental foramenMental fossa

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a. lingual foramenb. genial tuberclesc. mental ridged. mental fossa

Mandibular Incisor

a b c

d

The ThinkerAuguste Rodin, 1881


Mental foramenInferior alveolar (Mandibular) canal


Mylohyoid (Internal oblique) ridgeSubmandibular gland fossaInferior border of the mandible


External oblique ridgeInferior border of the mandible


Genial tuberclesMental Ridge

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a = Lingual foramenb = Mental ridge

lingual view


a a

b

b = genial tubercles

a = lingual foramen c = mental ridge

d = mental fossa

ab

cd

facial viewlingual viewLingual view 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 pathosis.

facial view Mandibular Canine

ab

a = mental ridgeb = genial tubercles/

lingual foramenc = mental foramen

c

b2

a = mental ridgec = mental foramen b2 = lingual foramen

b1 = genial tubercles

facial view lingual view

dc

da

db1

db2

Lingual foramen/ genial tubercles.

lingual view

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The red arrows identify the mandibular canal and the blue arrow points to the mental foramen.

facial view


Inferior border of the mandible

Mandibular Premolar

a = mylohyoid ridgeb = mandibular canalc = submandibular gland fossad = mental foramen


Submandibular gland fossa


Mental Foramen and Inferior Alveolar Canal

Mandibular Molar

a = external oblique ridgeb = mylohyoid ridgec = mandibular canald = submandibular gland fossa

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facial view

b

a = external oblique ridgec = mandibular canal

b = mylohyoid ridged = submandibular gland

fossa

c

ab

dd


External oblique ridgeInternal oblique ridge (a.k.a mylohyoid ridge)

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.

lingual view

ab

cdd

a = external oblique ridgeb = mylohyoid ridgec = mandibular canal (inferior border)d = submandibular gland fossa

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).

facial view

The mandibular canal (red arrows identify inferior border of canal) usually runs very close to the roots of the molars, especially the third molar.

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Restorations

GoldAmalgamTitaniumStainless SteelGutta PerchaPorcelainCompositesCements and Liners

Restorations

Metallic RestorationsBases and liners

Restorations

Implant restorations

Restorations

Stainless steel postRoot-end amalgam

Restorations

PorcelainGoldGutta perchaStainless steel

Restorations

Composites: Radiolucent and Radiopaque

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Restorations

Posterior composites

Acknowledgement

Thanks to OSU College of Dentistry for the use of some of the slides, diagrams, and radiographs.

Questions

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intraoral radiographic anatomy

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