Dental extra-oral radiography ppt final.pptx

Dental extraoral radiography

1. EXTRA ORAL RADIOGRAPHY

2. STANDARD OCCIPITOMENTAL/ PNS/WATERS VIEW Indications: Investigations of the maxillary antrum Detecting middle third facial factures: Le Fort I, II, & III Zygomatic complex Naso ethmoidal complex Orbital blow out Coronoid process fractures Investigation of frontal and ethmoidal sinuses. Investigation of sphenoidal sinus

3. Technique and positioning 1. The patient is positioned facing the film with the head tipped back so that the nose tip and chin are touching the cassette 2. The X- ray beam is positioned with the central ray horizontal centered through the occiput.

4. PA SKULL (postero – anterior of the skull) Indications: Fractures of the skull vault Investigations of the frontal sinus Conditions affecting the cranium , particularly: Pagets disease Multiple myeloma Hyperparathyroidism Intra cranial calcification

5. Technique and positioning The patient is positioned facing the film with the head tipped forwards so that the tip of the nose and the forehead touch the film. The X- ray beam is positioned with the central ray horizontal centered through the occiput

6. REVERSE TOWNE`S Indications: High fractures of the condylar necks Intracapsular fractures of the TMJ Evaluation of the articular surfaces of the condyle head Condylar hypo or hyperplasia.

7. Technique and positioning 1. The patient is positioned facing the film with the head tipped forwards so that the tip of the nose and the forehead touch the film, but in addition the mouth is kept wide open 2. The X- ray beam is positioned with the central ray pointed upward 30 , from below the occiput centered through the condyles.

8. SUBMENTO VERTEX (SMV) Indications: Destructive/ expansile lesions affecting the palate, pterygoid region or base of the skull. Fractures of the zygomatic arches; to show these thin bones the SMV is taken with reduced exposure factors. (Jug handle view)

9. Technique and positioning The patient is positioned facing away from the film. The head is tipped backwards as far as possible, so that the vertex of the skull touches 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. IMPORTANT: this position is contraindicated in patients with neck injuries

10. JUG HANDLE VIEW

11. LATERAL SKULL / LATERAL CEPHALOGRAM Indications: Fractures of the cranium and the cranial base. Middle third fractures, to show possible downward displacement. Investigations of the frontal, sphenoidal and maxillary sinuses. Conditions affecting the skull particularly; Pagets disease Multiple Myeloma Hyperparathyroidism Conditions affecting the sella turcica, such as tumour of pituitary glands.

12. Technique and positioning The patient is positioned such that the sagittal plane of the head is parallel to the film The X ray tube head is positioned such that the central ray is horizontal and perpendicular to the sagittal plane and centered through the external auditory meatus.

13. LATERAL OBLIQUE MANDIBLE Body projection Ramus projection Indications Pathologies in ramus & body of mandible Salivary calculi Trauma evaluation

14. Positioning & Technique Extend patients neck and tilt to side of interest Rest the side of face on extra oral cassette For body projection central beam is projected through angle of mandible on opposite side For ramus projection central beam is projected below first molar on opposite side

15. OPG Indications Fracture of mandible Cyst & Tumors Impacted teeth In patients with Trismus where IOPA is not possible Evaluate eruption pattern /status Periodontal assessment

16. RADIOGRAPHY OF THE TEMPOROMANDIBULAR JOINTS : Transcranial: Indications : Useful in detecting arthritic changes on the articular surface. To evaluate the joint’s bony relationship. Central ray : A.Postauricular or Lindblom technique : Point of entry of the central ray is ½” behind and 2” above the auditory meatus B.Grewcock approach : Central ray enters through a point 2” above the external auditory meatus

17. 2 . Transpharyngeal (Infracranial or McQueen Dell technique: Indication: To evaluate the temporomandibular joint as in this view it is projected into the shadow of air containing spaces of the nasopharynx,which helps to increase the contrast of various parts of the joint. Central ray: It is directed through the mandibular notch from the opposite side cranially,at an angle of -5 to -10 degree posteriorly .

18. 3.Transorbital (Zimmer Projection ): Indication: To evaluate the articular surface and the articular eminence. Central ray : It is directed to the joint of interest,at an angle of +20 degree to strike the cassette at right angles. The point of entry may be taken at: A. Pupil of the same eye B. Medial canthus of the same eye C. Medial canthus of the opposite eye .