ch 23 exam 3 extraoral radiography

  1. the most common extraoral film is the
    panoramic radiograph
  2. used to image large areas of the skull or jaws
    extraoral radiography
  3. The extraoral film is typically used for the following purposes (7)
    • Evaluate large areas of the skull and jaws
    • evaluate growth and development
    • evaluate impacted teeth
    • detect diseases, lesions, and conditions of the jaws
    • examine the extent of large lesions
    • evaluate trauma
    • evaluate teh temporomandibular joint area
  4. Equipment for extraoral radiographs (5)
    • x-ray unit
    • film
    • intensifying screens
    • cassette
    • grid
  5. special extention arm used in conjunction with teh x-ray tube head
    cephalostat (craniostat)
  6. includes a film holderand head positioner that allow the dental radiographer to position both film and patient easily
  7. Where is most extaoral film placed?
    in cassettes with intensifying screens
  8. sensitive to the light emitted from intensifying screens
    screen film
  9. sizes of film most often used in extraoral film?
    5x7 8x10
  10. a nonscreen film that does not require the use of screens for exposure
    occlusal film
  11. film that requires more exposure
    nonscreen film
  12. device that converts x-ray energy into visible light; the light then exposes the screen film
    intensifying screens
  13. calcium tungstate screens emit what color light
    rare earth screens emit what color light
    • blue
    • green
  14. which screens require less exposure
    rare earth screens
  15. holds the film in tight contact with the intensifying screen and protects the film from exposure to light
  16. rigid, constructed of plastic on the front and metal on the back; permits the passage of the x-ray beam through the front side (tube side)
  17. a device used to reduce the amount of scatter radiation that reaches an extraoral film during exposure
  18. what are the effects of scatter radiation
    • cause film fog
    • reduce film contrast
  19. can be used to decrease film fog and increase the contrast of the radiographic image
  20. to compensate for the lead strips found in the grid, what happens to the exposure time
  21. patient preparation for extraoral radiography(3)
    • explain the procedure to the patient
    • place a lead apron WITHOUT a thyroid collar over tha patient and secure it
    • romve all objects form the head and neck region that may interfere with film exposure
  22. used to examine the posterior region of the mandible and is valuable for use in children, in patients wiht limited jaw opening dut to fracure or swelling, and in patients who have difficulty stabalizing or tolerating intraoral film placement
    lateral jaw radiography
  23. which is preferred, panoramic radiograph or lateral jaw radiograph? why?
    panoramic, bc more diagnostic info can be obtained
  24. does lateral jaw rediography require the use of a special x-ray unit?
    no, a standard intraoral x-ray machine may be used
  25. 2 techniques used with lateral jaw projection
    • body of mandible
    • ramus of mandible
  26. purpose of the lateral jaw projection-body of the mandible is to evalute (3)
    • impacted teeth,
    • fracures, and
    • lesions located in the body of the mandible
  27. Film placment, head position and x-ray beam point of entry for lateral jaw, body of the mandible and ramus of the mandible
    • film placement:
    • flat against cheek
    • centered over body of the mandible (for body of the mandible)
    • centered over ramus of the madible (for ramus of the mandible)

    • Head postition:
    • tipped 15 degrees toward side being imaged
    • chin extended and elevated

    • x-ray beam point of entry for body of the mandible:
    • below inferior border of mandible
    • verticle angulation -15 to -20 degrees
    • perpendicular to horizontal plane of cassette

    • x-ray beam point of entry for ramus of the mandible:
    • posterior to third molar area
    • vertical angulation -15 to-20 degrees
    • perpendicular to horizontal plane of cassette
  28. used to examine the bones of the face and skull and is most often used in oral surgery and orthodontics
    skull radiography
  29. the most common skull radiographs used in dentistry include the following (5)
    • lateral cephalometric
    • posteroanterior projection
    • waters projection
    • submentovertex projection
    • reverse towne projection
  30. Film placement of all five skull radiographs
    • cassette perpendicular to floor
    • long axis horizontal
  31. X-ray beam point of entry for all five skull radiographs
    center cassette perpendicular to cassette
  32. head position for lateral cephalometric
    • left side near cassette
    • MSP perpendicular to floor
    • FP // to floor
  33. head postion for posteroanterior
    • forehead and nose tough cassette
    • MSP perpendicular to floor
    • FP // to floor
  34. head position for waters
    • chin touches cassette
    • tip of nose 1-2 inches from cassette
    • MSP perpendicular to floor
  35. head postion for submentovertex
    • head tipped back
    • top of head touches cassette
    • MSP and FP perpendicular to floor
  36. head position for reverse towne
    • Head tipped down
    • Mough open
    • top of forehead touches cassette
    • MSP perpendicular to floor
  37. purpose is to evaluate facial growth and development, trauma, and disease and developmental abnormalities
    lateral cephalometric projection
  38. This projection demonstrates the bones of the face and skull as well as the soft tissure profile of the face
    lateral cephalometric projection
  39. the soft tissure outline of the face is more readily seen on the resulting radiograph whe what is used
    a fliter
  40. where does the filter go
    • ath the x-ray source, or
    • between the patient and the film
  41. what is the purpose of the filter
    • to remove some of the patient x-rays
    • enhance the image of the soft tissue profile
  42. a line extending from the top of the ear canal to the bottom of the eye socket
    Frankfort plane (FP)
  43. purpose is to evaluate facial groth and development, trauma and disease and developmental abnormalities
    posteroanterior projection
  44. these projections demonstrates the forntal and ethmoid sinuses, the orbits and the nasl cavity
    • Posteroanterior projection
    • waters projection
  45. MSP
    Midsagital plane
  46. Purpose is to evaluate the maxillary sinus area
    waters projection
  47. Purpose is to identify the position of the condyles, semonstrate the base of the skull, adn evaluate fractures of the zygomatic arch
    submentovertex projection
  48. this projection demonstrates the sphenoid and ethmoid sinuses and teh lateral wall of the maxillary sinus
    submentovertex projection
  49. purpose is to idnetify fractures of teh condylar neck and ramus area
    reverse towne projection
  50. What makes up the TMJ
    • temporal bone
    • condyle of the mandible
    • glenoid fossa
    • articular eminence of the temporal bone
    • articular disk
Card Set
ch 23 exam 3 extraoral radiography
extraoral radiography