ORAL & MAXILLOFACIAL RADIOGRAPHY IN TRAUMADr. Tahmasub Faraz TayyabRegistrarOral & Maxillofacial SurgeryUniversity Of LahorePakistan

PLANES USED IN SKULL RADIOGRAPHYThe Median Sagittal plane. A vertical plane dividing the skull into 2

symmetrical right and left halves when viewed from the anterior aspect.

The Anthropological plane This plane splits the skull into upper and

lower halves passing along the anthropological baselines.

The Auricular plane This plane divides the skull into anterior and

posterior compartments along the Auricular lines.

Major body planes used in Skull radiography

Median S agittal Auricular Anthropological

LINES USED IN SKULL RADIOGRAPHYThe Anthropological line The Isometric “Baseline” which runs from the inferior

orbital margin to the upper border of the external auditory meatus (EAM)

The Orbital-Meatal Line The original “Baseline” which runs from the outer

canthus of the eye to the centre of the external auditory meatus

The Interpupillary line The line connects the centres of the orbits and is at

90 degree to the median sagittal plane.

NOTE: there is a difference of 10 to 15 degrees between the Orbital-Meatal line and the anthropological line.

PLAIN FILM RADIOGRAPHY Facial series

Standard occipitomental (0° OM) 30° occipitomental (30° OM) Water’s view (PA view with cephalad angulation) (PA skull) sometimes referred to as occipitofrontal

(OF) Caldwell view (PA view) Submento-vertex (SMV) Jug Handle View Lateral Skull Upper Occlusal

PLAIN FILM RADIOGRAPHY Mandible Series

Lower Occlusal Panoramic Radiograph (OPG) Right & left lateral oblique view of mandible PA view of mandible Reverse Towne’s

STANDARD OCCIPITOMENTAL (0° OM)

This projection shows the facial skeleton and maxillary antra, and avoids superimposition of the dense bones of the base of the skull.

In this projection the petrous bones are projected below the maxillary antra so whole of the lateral maxillary wall is clear.

MAIN INDICATIONS

Detecting the following middle third facial fractures:

LeFortI , Le Fort II & Le Fort III Zygomatic complex Naso-ethmoidal complex Orbital blow-out Coronoid process fractures Investigation of the frontal and ethmoidal sinuses Investigation of the sphenoidal sinus (projection

needs to be taken with the patient's mouth open).

TECHNIQUE AND POSITIONING

The patient is positioned facing the film with the head tipped back so the radiographic baseline is at 45° to the film, the so-called nose-chin position.

The X-ray tube head is positioned with the central ray horizontal (0°) centered through the occiput

30° OCCIPITOMENTAL (30° OM)

This projection also shows the facial skeleton, but from a different angle to 0° OM, enabling certain bony displacements to be detected.

This projection provides a superior view of the malar arches and the anterior aspect of the inferior orbital margins.

MAIN INDICATIONS

Detecting the following middle third facial fractures:

LeFortI Le Fort II Le Fort III Coronoid process fractures.

TECHNIQUE AND POSITIONING

The patient is in exactly the same position as for the 0° OM, i.e. the head tipped back, radiographic baseline at 45° to the film, in the nose-chin position.

The X-ray tube head is aimed downwards from above the head, with the central ray at 30° to the horizontal, centered through the lower border of the orbit

PA SKULL

This projection shows the skull vault, primarily the frontal bones and the jaws.

MAIN INDICATIONS

Fractures of the skull vault Investigation of the frontal sinuses Conditions affecting the cranium,

particularly: Paget's disease multiple myeloma hyperparathyroidism Intracranial calcification.

TECHNIQUE AND POSITIONING

The patient is positioned facing the film with the head tipped forwards so that the forehead and tip of the nose touch the film — the so-called forehead-nose position. The radiographic baseline is horizontal and at right angles to the film.

The X-ray tube head is positioned with the central ray horizontal (0°) centered through the occiput and aimed to exit at nasion .

OCCIPITOFRONTAL 15° -20° (CALDWELL)

The Caldwell view is a caudally angled PA radiograph of the skull, designed to better visualize the paranasal sinuses, especially the frontal sinuses.

OF 0° (PA Skull): Petrous ridges completely superimposed with orbits

OF10°: Petrous ridges appears in the middle of the orbit

OF 30°: Petrous ridges appears just below the orbital margins

TECHNIQUE AND POSITIONING The patient is positioned facing the film with

the head tipped forwards so that the forehead and tip of the nose touch the film — the so-called forehead-nose position. The radiographic baseline is horizontal and at right angles to the film.

The X-ray tube head is positioned with the central ray horizontal (15-20°) centered through the occiput and aimed to exit at nasion .

WATER’S VIEW (PNS) This projection was a modification of OF

projection in order to obtain view of maxillary antra while retaining a view of the frontal and ethmoid sinuses.

The patient is positioned facing the film with the head tipped back so the radiographic baseline is at 37° to the film, the so-called nose-chin position.

The X-ray tube head is aimed perpendicular to the image receptor and centered in the area of maxillary sinuses.

SUBMENTO-VERTEX (SMV)

This projection shows the base of the skull, zygomatic arches, sphenoidal sinuses and facial skeleton from below.

MAIN INDICATIONS

Destructive/expansive lesions affecting the palate, pterygoid region or base of skull

Investigation of the sphenoidal sinus Assessment of the thickness (medio-lateral)

of the posterior part of the mandible before osteotomy

Fracture of the Zygomatic arches — to show these thin bones the SMV is taken with reduced exposure factors.

TECHNIQUE AND POSITIONING

The patient is positioned facing away from the film. The head is tipped backwards as far as is possible, so the vertex of the skull touches the film. In this position, the radiographic baseline, is vertical and parallel to the film.

The X-ray tube head is aimed upwards from below the chin, with the central ray at 5° to the horizontal, centered on an imaginary line joining the lower first molars .

Note: The head positioning required for this projection means it is contraindicated in patients with suspected neck injuries, especially suspected fracture of the odontoid peg.

JUG HANDLE VIEW Same as that in

submentovertex. The exposure time

for the zygomatic arch is reduced to approximately one-third the normal exposure time for a submentovertex projection

TRUE LATERAL SKULL

This projection shows the skull vault and facial skeleton from the lateral aspect. The main difference between the true lateral skull and the true cephalometric lateral skull taken on the cephalostat is that the true lateral skull is not standardized or reproducible. This view is used when a single lateral view of the skull is required but not in orthodontics or growth studies.

MAIN INDICATIONS

Fractures of the cranium and the cranial base Middle third facial fractures, to show possible

downward and backward displacement of the maxillae

Investigation of the frontal, sphenoidal and maxillary sinuses

Conditions affecting the skull vault, particularly: Paget's disease multiple myeloma hyperparathyroidism Conditions affecting the sella turcica, such as:

Tumor of the pituitary gland in acromegaly.

TECHNIQUE AND POSITIONING

The patient is positioned with the head turned through 90°, so the side of the face touches the film. In this position, the sagittal plane of the head is parallel to the film.

The X-ray tube head is positioned with the central ray horizontal (0°) and perpendicular to the sagittal plane and the film, centered through the external auditory meatus .

UPPER OCCLUSAL Occlusal radiography is defined as those

intraoral radiographic techniques taken using a dental X-ray set where the film packet or a small intra

Maxillary occlusal projections Upper standard occlusal (standard occlusal) Upper oblique occlusal (oblique occlusal) Vertex occlusal (vertex occlusal).oral cassette

is placed in the occlusal plane.

UPPER STANDARD OCCLUSAL This projection

shows the anterior part of the maxilla and the upper anterior teeth.

MAIN INDICATIONS Periapical assessment of the upper anterior teeth,

especially in children but also in adults unable to tolerate periapical films

Detecting the presence of unerupted canines, supernumeraries and odontomes

As the midline view, when using the parallax method for determining the bucco/palatal position of unerupted canines

Evaluation of the size and extent of lesions such as cysts or tumors in the anterior maxilla

Assessment of fractures of the anterior teeth and alveolar bone. It is especially useful in children following trauma because film placement is straightforward.

TECHNIQUE AND POSITIONING The patient is seated with the head supported and

with the occlusal plane horizontal and parallel to the floor

The film packet, with the white (pebbly) surface facing uppermost, is placed flat into the mouth on to the occlusal surfaces of the lower teeth. The patient is asked to bite together gently. The film packet is placed centrally in the mouth with its long axis crossways in adults and anteroposteriorly in children.

The X-ray tubehead is positioned above the patient in the midline, aiming downwards through the bridge of the nose at an angle of 65°-70° to the film packet

UPPER OBLIQUE OCCLUSAL This projection

shows the posterior part of the maxilla and the upper posterior teeth on one side.

MAIN INDICATIONS Periapical assessment of the upper posterior

teeth, especially in adults unable to tolerate periapical films

Evaluation of the size and extent of lesions such as cysts, tumors or osteodystrophies affecting the posterior maxilla

Assessment of the condition of the antral floor As an aid to determining the position of roots

displaced inadvertently into the antrum during attempted extraction of upper posterior teeth

Assessment of fractures of the posterior teeth and associated alveolar bone including the tuberosity.

TECHNIQUE AND POSITIONING The patient is seated with the head supported

and with the occlusal plane horizontal and parallel to the floor.

The film packet, with the white (pebbly) surface facing uppermost, is inserted into the mouth on to the occlusal surfaces of the lower teeth, with its long axis anteroposteriorly. It is placed to the side of the mouth under investigation, and the patient is asked to bite together gently.

The X-ray tubehead is positioned to the side of the patient's face, aiming downwards through the cheek at an angle of 65°-70° to the film,centring on the region of interest

VERTEX OCCLUSAL This projection shows a plan view of the

tooth bearing portion of the maxilla from above. To obtain this view the X-ray beam has to pass through a considerable amount of tissue, delivering a large dose of radiation to the patient.

Main indication for this projecton is assessment of the bucco/palatal position of unerupted canines.

TECHNIQUE AND POSITIONING The patient is seated with the head supported

and with the occlusal plane horizontal and parallel to the floor.

Film packet is inserted into the mouth on to the occlusal surfaces of the lower teeth, with its long axis anteroposteriorly and the patient is asked to bite on to it.

The X-ray tube head is positioned above the patient, in the midline, aiming downwards through the vertex of the skull. The main beam is therefore aimed approximately down the long axis of the root canals of the upper incisor teeth.

DISADVANTAGES The primary X-ray beam may be in direct line

with the reproductive organs. A relatively long exposure time is

needed(about 1second) despite the use of intensifying screens.

There is direct radiation to the pituitary gland and the lens of the eye.

If the X-ray beam is positioned too far anteriorly, superimposition of the shadow of the frontal bones may obscure the anterior part of the maxilla.

LOWER OCCLUSAL

Mandibular occlusal projections Lower 90° occlusal (true occlusal) Lower 45 ° occlusal (standard occlusal) Lower oblique occlusal (oblique occlusal)

LOWER 90° OCCLUSAL

This projection shows a plan view of the tooth bearing portion of the mandible and the floor of the mouth.

MAIN INDICATIONS

Detection of the presence and position of radiopaque calculi in the submandibular salivary ducts

Assessment of the bucco-lingual position of unerupted mandibular teeth

Evaluation of the bucco-lingual expansion of the body of the mandible by cysts, tumours or osteodystrophies

Assessment of displacement fractures of the anterior body of the mandible in the horizontal plane.

TECHNIQUE AND POSITIONING

The film packet, with the white (pebbly) surface facing downwards, is placed centrally into the mouth, on to the occlusal surfaces of the lower teeth, with its long axis crossways. The patient is asked to bite together gently.

The patient then leans forwards and then tips the head backwards as far as is comfortable, where it is supported.

The X-ray tubehead is placed below the patient's chin, in the midline, centring on an imaginary line joining the first molars, at an angle of 90° to the film .

Note: The lower 90° occlusal is mounted as if the examiner were looking into the patient's mouth. The radiograph is therefore mounted with the embossed dot pointing away from the examiner.

LOWER 45° OCCLUSAL

T his projection is taken to show the lower anterior teeth and the anterior part of the mandible. The resultant radiograph resembles a large bisected angle technique periapical of this region.

MAIN INDICATIONS

Periapical assessment of the lower incisor teeth, especially useful in adults and children unable to tolerate periapical films

Evaluation of the size and extent of lesions such as cysts or tumours affecting the anterior part of the mandible

Assessment of displacement fractures of the anterior mandible in the vertical plane.

TECHNIQUE AND POSITIONING

The patient is seated with the head supported and with the occlusal plane horizontal and parallel to the floor.

The film packet, with the white (pebbly)surface facing downwards, is placed centrally into the mouth, on to the occlusal surfaces of the lower teeth, with its long axis anteroposteriorly, and the patient is asked to bite gently together.

The X-ray tubehead is positioned in the midline, centring through the chin point, at an angle of 45° to the film

LOWER OBLIQUE OCCLUSAL

This projection is designed to allow the image of the submandibular salivary gland, on the side of interest, to be projected on to the film. However,because the X-ray beam is oblique, all the anatomical tissues shown are distorted.

MAIN INDICATIONS

Detection of radiopaque calculi in a submandibular salivary gland

Assessment of the bucco-lingual position of unerupted lower wisdom teeth

• Evaluation of the extent and expansion of cysts, tumours or osteodystrophies in the posterior part of the body and angle of the mandible.

TECHNIQUE AND POSITIONING

The film packet, with the white (pebbly) surface facing downwards, is inserted into the mouth, on to the occlusal surfaces of the lower teeth, over to the side under investigation, with its long axis anteroposteriorly. The patient is asked to bite together gently.

The patient's head is supported, then rotated away from the side under investigation and the chin is raised. This rotated positioning allows the subsequent positioning of the X-ray tube head.

The X-ray tubehead with circular collimator is aimed upwards and forwards towards the film, from below and behind the angle of the mandible and parallel to the lingual surface of the mandible

PANORAMIC RADIOGRAPH Most Common It is a technique for producing a single

tomographic image of facial structures that includes both maxillary and mandibular arches and their supporting structures

This is curvilinear variant of conventional tomography and is also used on the principle of the reciprocal movement of an x-ray source and an image receptor around a central point or plane called the image layer in which the object of interest is located.

OPG Ortho - straight Panoramic - An obstructed or a complete

view of the object in every direction Tomography – An x-ray technique for making

radiographs of layers of tissue in depth, without the interference of tissue above and below that level

MAIN INDICATIONSEvaluation of- Trauma Location of third molars Extensive dental or osseous disease Known or suspected large lesions Tooth development Retained teeth or root tips TMJ pain Dental anomalies etc.

POSTERO-ANTERIOR OF THE JAWS (PA JAWS/PA MANDIBLE)

This projection shows the posterior parts of the mandible. It is not suitable for showing the facial skeleton because of superimposition of the base of the skull and the nasal bones.

MAIN INDICATIONS

Fractures of the mandible involving the following sites: Posterior third of the body

Angles Rami

Low condylar necks Lesions such as cysts or tumors in the posterior third of the body or rami to note any medio-lateral expansion Mandibular hypoplasia or hyperplasia Maxillofacial deformities.

TECHNIQUE AND POSITIONING

The patient is in exactly the same position as for the PA skull, i.e. the head tipped forward, the radiographic baseline horizontal and perpendicular to the film in the forehead-nose position.

The X-ray tube head is again horizontal (0°), but now the central ray is centered through the cervical spine at the level of the rami of the mandible.

REVERSE TOWNE'S

This projection shows the condylar heads and necks. The original Towne's view (an AP projection) was designed to show the occipital region, but also showed the condyles. However, since all skull views used in dentistry are taken conventionally in the PA direction, the reverse Towne's (a PA projection) is used.

MAIN INDICATIONS

High fractures of the condylar necks Intra capsular fractures of the TMJ Investigation of the quality of the articular Surfaces of the condylar heads in TMJ

disorders Condylar hypoplasia or hyperplasia.

TECHNIQUE AND POSITIONING

The patient is in the PA position, i.e. the head tipped forwards in the forehead-nose position, but in addition the mouth is open. The radiographic baseline is horizontal and at right angles to the film. Opening the mouth takes the condylar heads out of the glenoid fossae so they can be seen.

The X-ray tube head is aimed upwards from below the occiput, with the central ray at 30° to the horizontal, centered through the condyles.

LATERAL OBLIQUE The Film is positioned against the patient's

cheek overlying the ascending ramus and the posterior aspect of the condyle of the mandible under investigation.

The Film is positioned so that its lower border is parallel with the inferior border of the mandible but lies at least 2 cm below it

The mandible is extended as far as possible. The X-Ray tube is centered from the

contralateral side of the mandible at a point 2 cm below the inferior border in the region of the first/second permanent molar with angulation of 10 degrees cephalad or caudal

RADIOLOGICAL INTERPRETATION OF FACIAL TRAUMA

You see what you look for…!!!!

CAMPBELL’S AND TRAPNELL’S LINES

Occipitomental projection

Fractures & other signs are commonly found.

CAMPBELL’S AND TRAPNELL’S LINES

1st Line: Acrossthe zygomaticofrontal, the superior margin of orbit and the frontal sinus.

2nd Line: Across the zygomatic arch, zygomatic body, inferior orbital margin and nasal bone.

3rd Line: Across the condyles, coronoid and maxillary sinus.

4th Line: Across the mandibular ramus and the occlusal Plane

5th line: (Trapnell’s Line) Across the inferior border of mandible and from angle to angle.

DOLAN & JACOBY’S LINE(A) Orbital line. It extends along the inner margins of the

lateral, inferior and medial walls of the orbit, passing over the nasal arch to follow the same structures on the opposite side

B) Zygomatic line.

It extends along the superior margin of the arch and body of the zygoma, passing along the lateral margin of the frontal process of zygoma to the zygomaticofrontal suture

DOLAN & JACOBY’S LINE Maxillary Line

It extends along the inferior margin of the zygomatic arch, the inferior margin of the body and buttress of the zygoma and the lateral wall of the maxillary sinus.

4 ‘S’ BY DELBALSO ET AL Symmetry.

Sharpness – Bright sign, Trapdoor sign.

Sinus.

Soft tissues. Swelling, foreign bodies, emphysema.

HOT SITES OF FRACTURE ON FACE

HOT SITES OF FRACTURE ON FACE Three fracture pattrens following lefort’s three line

s of weekness were recongnized i.e. Lefoet-1, Lefort-2 & Le-fort-3.

If these lines of weakness are mapped out onto the image of an occipitomental 10 degree or modified caldwell projection, than a pattren emerges and certain sites provide likely hunting ground for recognizing injury (hot sites).

These are the areas where fractures are easily manifested to the observer Particular attention should therefore be paid to these areas.

These lines of weakness are not precise and vary from individual to individual. It doesn’t obeviate the need for a complete study of the radiograph.

RADIOGRAPHIC SIGNS OF FRACTURE Direct Signs Separation sign. Sutural diastasis. Overlap sign. Abnormal linear density Disappearing fragment

sign. Abnormal angulation. Step deformity Displaced Bone Widening of PDL

Ligament

RADIOGRAPHIC SIGNS OF FRACTUREIndirect signs

Soft tissue swelling. localized attention to that part Paranasal sinus opacification. Air in the soft tissues. Changes in occlusal plane

CHECKLIST Can be obtained to screen for facial injury if

CT is not Immediately available Multiple plain film projections are relative to

‘canthomeatal line’ Proper positioning (of patient’s head),

alignment of xray beam is critical for evaluation because facial skeletal anatomy is complex

Remember: plain film is a 2D image of a 3D object, Golden rule of Thumb is to Obtain two radiographs at right angleto each other in order to visualize a 3D object in a 2D radiograph

CHECKLIST Rule of symmetry: two sides of the face are

quite symmetrical, Symmetry is usual, and asymmetry is suspect

Multiplicity: fractures of facial bones are frequently multiple.

Do not stop looking for others when see one