3 radio. anatomy.&interpert i

05/02/2305/02/23 OelshallOelshall 11

Dental RadiographicDental Radiographic anatomy & interpretation

Part I

Dr. Ossama EL-ShallProfessor & Chairman, Faculty of Professor & Chairman, Faculty of

Dental Medicine for girls, Al-Azhar Dental Medicine for girls, Al-Azhar University, Cairo Egypt.University, Cairo Egypt.

E.mail address: [email protected] address: [email protected]


Dental radiographic interpretation


Dental 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 completely The 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 be All 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 normal Knowing and familiarity with all normal anatomical landmarks as well as all various anatomical landmarks as well as all various pathological conditions that may affect the area of pathological conditions that may affect the area of interest.interest.


Principles of radiographic Principles of radiographic interpretationinterpretation

Interpretation of a radiograph is not a Interpretation of a radiograph is not a diagnosis by itself, but it is an diagnostic aid diagnosis 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 by Final diagnosis can be reached by performing a full case history, clinical performing a full case history, clinical examination, special investigations and examination, 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 recognition It is the identification and recognition of the area which the view shows, for of the area which the view shows, for example: Upper anterior area, TMJ example: Upper anterior area, TMJ area, Lower molar area……………….. area, Lower molar area………………..


ObservationObservation

All shadows, other than the localized All shadows, other than the localized shadows of the normal landmarks must shadows of the normal landmarks must be observed.be observed.

For example: shadows in crowns, For example: shadows in crowns, cervical area, roots, restorations, size of cervical area, roots, restorations, size of root canals, periodontal membrane root canals, periodontal membrane space, periapical area, alveolar crest, space, periapical area, alveolar crest, foreign bodies, integrity of bone …………foreign bodies, integrity of bone …………


General considerationGeneral considerationA radiograph shows only 2 dimensions of a 3 A radiograph shows only 2 dimensions of a 3 dimensional object (width and height but not dimensional object (width and height but not the depth)the depth)

Cervical burnout: usually appears as cervical Cervical burnout: usually appears as cervical RL and misinterpreted by caries; this occurs RL and misinterpreted by caries; this occurs due to less density and more penetration of due to less density and more penetration of rays.rays.

Pulp exposure never to be determined from Pulp exposure never to be determined from radiograph but only the proximity to the radiograph but only the proximity to the pulp. pulp.


InterpretationInterpretationStudying the features of Studying the features of teethteeth and and

bonebone

TeethTeeth Study the whole tooth, (crown, root Study the whole tooth, (crown, root

enamel, pulp….), number of teeth enamel, pulp….), number of teeth and finally supporting structures, and finally supporting structures, (Periodontal membrane space, (Periodontal membrane space, lamina dura, alveolar crest) lamina 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 margin3- 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 1- Well-defined margin with or without sclerotic border denoting a without sclerotic border denoting a slowly growing or chronic condition slowly growing or chronic condition such as cyst and granuloma.such as cyst and granuloma.

2- ill-defined margin, denoting acute 2- ill-defined margin, denoting acute active condition destroying bone in active condition destroying bone in all directions, such as abscess, or all directions, 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 4-Effects on surrounding tissues.tissues.

1-May cause expansion, 1-May cause expansion, resorption, destruction or resorption, destruction or thinning of bone.thinning of bone.

2-Compressed adjacent tissues as 2-Compressed adjacent tissues as max. sinus or nasal cavity max. sinus or nasal cavity

3-Displacement of teeth, 3-Displacement of teeth, divergence or resorption.divergence or resorption.

4-Affection of lamina dura. 4-Affection of lamina dura.


5- Changes in structure5- Changes in structure

1-Ground glass appearance; fine 1-Ground glass appearance; fine granules of bony trabeculation.granules of bony trabeculation.

2-Cotton wool appearance; irregular 2-Cotton wool appearance; irregular ill-defined RO areas within area of ill-defined RO areas within area of more RLmore RL

3-Honeycomb; multilocular lesion 3-Honeycomb; multilocular lesion with small compartments.with small compartments.

4-Granular appearance: homogenous 4-Granular appearance: homogenous due to loss of contrast between RL due to loss of contrast between RL & RO & RO


CorrelationCorrelationThe final step is to correlate all of The final step is to correlate all of the radiographic features to reach a the radiographic features to reach a radiographic differential diagnosis.radiographic differential diagnosis.

Then to draw a final diagnosis, we Then to draw a final diagnosis, we have to correlate other data as case have to correlate other data as case history, clinical examination, and history, clinical examination, and other diagnostic aids with the other 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 foramenGenial 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 regionNasal 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 Median palatine suturesuture


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 septumb = inferior chonchac = nasal fossad = anterior nasal spine

e = incisive foramenf = median palatal suture

ad

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 fossab = maxillary sinusc = lateral fossa

(a & b form inverted Y)

a

cb

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 processc = sinus septumd = maxillary sinus

a c d dca

facial view


5-Maxillary sinus:5-Maxillary sinus: The maxillary sinus with The maxillary sinus with

its thin bony walls, its its thin bony walls, its thin mucosa, and its vast thin mucosa, and its vast air space, produce an air space, produce an extremely dark image extremely dark image (10)(10) deep to the maxillary deep to the maxillary teeth. teeth.

Its outlines, particularly its Its outlines, particularly its floor, are clearly floor, are clearly delineated by delicate delineated by delicate radiopaque lines radiopaque lines (11).(11).


1-Body of zygoma1-Body of zygoma6-Apices of roots6-Apices of roots7-floor of the sinus7-floor of the sinus8-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 the In general the floor of the sinus is approximately sinus is approximately

coincidental with the coincidental with the location of the apices of location of the apices of

the roots of the upper the roots of the upper teeth,(bicuspids and first teeth,(bicuspids and first

two molars). two molars).

But there is often as much But there is often as much as 2 or even 3 millimeters as 2 or even 3 millimeters

of maxillary bone of maxillary bone between the root ends and between the root ends and

sinus floor.sinus floor.


In other cases the sinus floor dips so deeply In other cases the sinus floor dips so deeply between the roots of the maxillary teeth that between the roots of the maxillary teeth that

the latter appear to project into it for as much the 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 sinusc = hamular process g = sinus recessd = pterygoid plates* image of impacted third molar superimposed

c

facial view

d

ba

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 foramenGenial 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 labial It is a bony prominence found on the labial aspect of the mandible near its inferior border and extended aspect of the mandible near its inferior border and extended from the premolar region to the symphysis area on which it from the premolar region to the symphysis area on which it takes an upward turn as it approach it. It appears as a takes 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 depression It is a slight depression

in the bone one the in the bone one the labial aspect of the labial aspect of the mandible. It appears mandible. It appears as a faint radiolucent as a faint radiolucent structure related to structure related to anterior area.anterior area. Notice: 7 is cervical burnout


b = genial tuberclesa = lingual foramen c = mental ridge

d = mental fossa

ab

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 ridgeb = mandibular canalc = submandibular gland fossad = mental foramen


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


c

b = mandibular canald = mental foramen

a = mylohyoid ridge (internal oblique)c = submandibular gland fossa

facial view lingual view

c

add 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 ridgeb = mylohyoid ridgec = mandibular canald = submandibular gland fossa


facial view lingual view

b

c

ab

a = external oblique ridgec = mandibular canal

b = mylohyoid ridged = 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

cdd

a = external oblique ridgeb = mylohyoid ridgec = mandibular canald = 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.


Normal anatomical Normal anatomical landmarks as seen in landmarks as seen in

occlusal filmsocclusal 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.


Normal anatomical Normal anatomical landmarks as seen in landmarks as seen in

panoramic viewspanoramic views


Misinterpretation of normal Misinterpretation of normal radiographic anatomical radiographic anatomical

landmarks with pathological landmarks 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 foramenBoth can be misinterpreted for a periapical Both can be misinterpreted for a periapical granuloma or any other periapical pathosis.granuloma or any other periapical pathosis.


To differentiate1- 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 cystTo differentiate:To differentiate:Check the normal radiographic appearance Check the normal radiographic appearance of the sinus with its septae.of the sinus with its septae.Take a radiograph of the other sinus to Take a radiograph of the other sinus to compare.compare.The radiolucency of the sinus (air filled) is The 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. sinuscyst

cyst

sinus

sinus


The Coronoid processThe Coronoid process

When it superimposed on the maxillary When it superimposed on the maxillary tubrosity, it can misinterpreted as impacted tubrosity, it can misinterpreted as impacted tooth.tooth.To differentiate: shifting tech.To differentiate: shifting tech.


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

The mental fossaThe mental fossa

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