1. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. Chapter 23 Extraoral Imaging

2. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 2 Dental Radiography  Questions  What equipment is used in extraoral imaging?  What is the purpose of each of the projections that is used for skull imaging?

3. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 3 Dental Radiography  Chapter 23 Reading  Iannucci & Howerton (pp. 274-289)

4. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 4 Dental Radiography  Chapter 23 Outline  Extraoral Imaging  Basic concepts  Step-by-step procedures  Extraoral projection techniques

5. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 5 Introduction  Iannucci & Howerton (p. 274)  Purpose  To present the basic concepts of extraoral imaging and describe the necessary patient and equipment preparations  To introduce a number of extraoral projection techniques and describe the receptor placement, patient positioning, and beam alignment for such projections

6. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 6 Basic Concepts  Iannucci & Howerton (pp. 274-275)  Extraoral radiograph  An image that is placed outside the mouth during x-ray exposure  Used to image large areas of the skull or jaws

7. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 7 Purpose and Use  Iannucci & Howerton (p. 275)  To evaluate large areas of the skull or jaws  To evaluate growth and development  To evaluate impacted teeth  To detect diseases, lesions, and conditions of the jaws  To examine the extent of large lesions  To evaluate trauma  To evaluate the temporomandibular joint area

8. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 8 Equipment  Iannucci & Howerton (p. 275)  X-ray unit  Film  Intensifying screens  Cassette  Grid

9. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 9 X-ray Unit  Iannucci & Howerton (p. 275) (Figs. 23-1, 23-2)  A standard intraoral x-ray machine may be used for a variety of extraoral projections.  Special head positioning and beam alignment devices can be added.  Some panoramic x-ray units can be used for extraoral projections.  The panoramic tubehead is used in conjunction with a special extension arm and a device known as a cephalostat or craniostat.

10. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 10 Film  Iannucci & Howerton (pp. 275-276)  Most extraoral exposures are made with screen film placed in a cassette with intensifying screens.  Screen film is sensitive to the light emitted from intensifying screens.  An occlusal film is a nonscreen film that may be used for some extraoral radiographs.

11. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 11 Intensifying Screens  Iannucci & Howerton (p. 276)  A device that converts x-ray energy into visible light; the light, in turn, exposes the screen film  The screen film must be compatible with the light emitted from the screen.

12. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 12 Cassette  Iannucci & Howerton (p. 276)  Purpose is to hold the receptor in tight contact with the intensifying screen and to protect the film from exposure to light.  Must be labeled to orient the finished image.  The front side is typically constructed of plastic, back side is made of metal.

13. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 13 Grid  Iannucci & Howerton (p. 276) (Fig. 23-3)  A device used to reduce the amount of scatter radiation that reached an extraoral film during exposure  A series of thin lead strips embedded in a material that permits passage of the x-ray beam  The grid is placed between the patient’s head and the film.  During exposure, the grid permits passage of the x-ray beam between the lead strips.  Scatter radiation is absorbed by the lead strips and does not reach the surface of the film.

14. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 14 Step-by-Step Procedures  Equipment Preparation  Patient Preparation  Patient Positioning

15. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 15 Step-by-step Procedures  Infection control procedures must be complete before exposing an extraoral receptor.  If an extraoral unit with cephalostat is used, the ear rods must be wiped with disinfectant between patients.

16. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 16 Equipment Preparation  Iannucci & Howerton (p. 276) (Procedure 23-1)  Load the extraoral cassette in the darkroom under safelight conditions.  Set the exposure factors according to the manufacturer’s recommendations.

17. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 17 Patient Preparation  Iannucci & Howerton (pp. 276-277) (Procedure 23-2)  Explain the radiographic procedure to the patient.  Place a lead apron without a thyroid collar over the patient and secure it.  Remove all objects from the head and neck region that may interfere with exposure.

18. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 18 Patient Positioning  Varies with each extraoral radiographic projection  Discussed in section on specific extraoral projection techniques

19. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 19 Extraoral Projection Techniques  Iannucci & Howerton (pp. 277-278) (Table 23-1)  Lateral Jaw Imaging  Skull Imaging  Temporomandibular Joint Imaging

20. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 20 Lateral Jaw Radiography  Iannucci & Howerton (pp. 277)  Used to examine the posterior region of the mandible  Includes Body of the mandible projection Body of the mandible projection Ramus of the mandible projection Ramus of the mandible projection

21. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 21 Body of the Mandible  Iannucci & Howerton (pp. 277, 279) (Fig. 23-4)  Purpose  To evaluate impacted teeth, fractures, and lesions located in the body of the mandible  Receptor placement  Flat against cheek  Centered over body of mandible  Head position  Tipped 15 degrees toward side being imaged  Chin extended and elevated

22. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 22 Body of the Mandible  Beam alignment  Below inferior border of mandible, vertical angulation -15 to -20 degrees  Perpendicular to horizontal plane of cassette  Exposure factors  Vary with the receptor, intensifying screens, and equipment used

23. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 23 Ramus of the Mandible  Iannucci & Howerton (pp. 277, 280) (Fig. 23-5)  Purpose  To evaluate impacted third molars, large lesions, and fractures that extend into the ramus of the mandible  Receptor placement  Flat against cheek, centered over ramus of mandible  Head position  Tipped 15 degrees toward side being imaged  Chin extended and elevated

24. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 24 Ramus of the Mandible  Beam alignment  Posterior to third molar area  Vertical angulation -15 to -20 degrees  Exposure factors  Vary with the receptor, intensifying screens, and equipment used

25. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 25 Skull Imaging  Iannucci & Howerton (pp. 277-278)  Used to examine the bones of the face and skull  Used most often in oral surgery and orthodontics  Includes: Lateral cephalometric projection Lateral cephalometric projection Posteroanterior projection Posteroanterior projection Waters projection Waters projection Submentovertex projection Submentovertex projection Reverse Towne projection Reverse Towne projection

26. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 26 Lateral Cephalometric Projection  Iannucci & Howerton (pp. 278, 281) (Fig. 23-6)  Purpose  To evaluate facial growth and development, trauma, and disease and developmental abnormalities  Receptor placement  Cassette perpendicular to the floor  Long axis of cassette horizontal

27. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 27 Lateral Cephalometric Projection  Head position  Left side of patient’s head near cassette  Midsagittal plane perpendicular to the floor  Frankfort plane parallel to the floor  Beam alignment  Central ray perpendicular to the cassette  Exposure factors  Vary with the receptor, intensifying screens, and equipment used

28. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 28 Posteroanterior Projection  Iannucci & Howerton (pp. 282-283) (Fig. 23-7)  Purpose  To evaluate facial growth and development, trauma, and disease and developmental abnormalities  Receptor placement  Cassette perpendicular to the floor  Long axis of cassette horizontal

29. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 29 Posteroanterior Projection  Head position  Forehead and nose touch cassette  Midsagittal plane perpendicular to the floor  Frankfort plane parallel to the floor  Beam alignment  Central ray perpendicular to the cassette  Exposure factors  Vary with the receptor, intensifying screens, and equipment used

30. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 30 Waters Projection  Iannucci & Howerton (pp. 282,284) (Fig. 23-8)  Purpose  To evaluate the maxillary sinus area  Receptor placement  Cassette perpendicular to the floor  Long axis of the cassette is vertical  Head position  Chin touches cassette  Tip of nose ½ -1 inch from cassette  Midsagittal plane perpendicular to the floor

31. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 31 Waters Projection  Beam alignment  Central ray through center of the head and perpendicular to the cassette  Exposure factors  Vary with the receptor, intensifying screens, and equipment used

32. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 32 Submentovertex Projection  Iannucci & Howerton (pp. 282, 285) (Fig. 23-9)  Purpose  To identify the position of the condyles, demonstrate the base of the skull, and evaluate fractures of the zygomatic arch  Receptor placement  Cassette perpendicular to the floor  Long axis of the cassette is vertical

33. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 33 Submentovertex Projection  Head position  Head tipped back  Top of head touches cassette  Midsagittal plane and Frankfort plane perpendicular to the floor  Beam alignment  Central ray through center of the head and perpendicular to the cassette  Exposure factors  Vary with the receptor, intensifying screens, and equipment used

34. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 34 Reverse Towne Projection  Iannucci & Howerton (pp. 282, 286) (Fig. 23-10)  Purpose  To identify fractures of the condylar neck and ramus area  Receptor placement  Cassette perpendicular to the floor  Long axis of the cassette is vertical

35. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 35 Reverse Towne Projection  Head position  Head tipped down  Mouth open wide as possible  Top of forehead touches cassette  Midsagittal plane perpendicular to the floor  Beam alignment  Central ray through center of the head and perpendicular to the cassette  Exposure factors  Vary with the receptor, intensifying screens, and equipment used

36. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 36 Temporomandibular Joint Imaging  Iannucci & Howerton (p. 282)  The joint includes the temporal bone and the mandible.  The glenoid fossa and articular eminence of the temporal bone, the condyle of the mandible, and the articular disk between the bones comprise the TMJ.  Includes Transcranial projection Transcranial projection Temporomandibular joint tomography Temporomandibular joint tomography

37. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 37 Transcranial Projection (Lindblom Technique)  Iannucci & Howerton (pp. 282, 287) (Fig. 23-11)  Purpose  To evaluate the superior surface of the condyle and the articular eminence  Receptor placement  Flat against patient’s ear  Centered over TMJ

38. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 38 Transcranial Projection  Head position  Midsagittal plane perpendicular to the floor and parallel with the cassette  Beam alignment  2 inches above and 0.5 inch behind the ear canal opening  Vertical angulation +25 degrees, horizontal angulation forward 20 degrees  Exposure factors  Vary with the receptor, intensifying screens, and equipment used

39. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 39 Temporomandibular Joint Tomography  Iannucci & Howerton (pp. 287-288) (Fig. 23-12)  Used to examine the temporomandibular joint  The location of the rotational point determines what plane of the head of the TM joint will be imaged.