1. Chapter 29 Extraoral Radiography and Alternate Imaging Modalities

2. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Objectives Define the key words. Describe the purpose and use of extraoral radiographs. List seven extraoral radiographs that contribute to the treatment of dental patients. Explain the need for proper extraoral film handling.

3. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Objectives Explain the role intensifying screens play in producing a radiographic image. Match blue- and green-light sensitive film with the appropriate intensifying screen. Explain the role of the extraoral film cassette. Describe how extraoral radiographs are labeled.

4. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Objectives Explain the need for proper care and cleaning of cassettes and intensifying screens. Explain the role grids play in extraoral radiography. Explain tomography and describe its role in oral health care. Explain cone beam computed tomography and describe its role in oral health care.

5. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Introduction Extraoral radiographs and alternate imaging modalities such as computed tomography record large areas of the dental arches, supporting facial structures, and skull using image receptors that are positioned outside the mouth.

6. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Introduction Knowing the types of extraoral radiographs and alternate imaging modalities, understanding the conditions that most likely benefit from each; and being able to recognize the different images are valuable skills.

7. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Introduction The dental assistant and/or hygienist may be asked to educate the patient about the procedure or assist with scheduling the patient’s appointment for the referral. Oral radiographers should be able to communicate professionally with other health care professionals.

8. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Figure 29-1 A combination panoramic and cephalometric dental x-ray unit. (Courtesy of Planmeca.)

9. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Purpose and Use of Extraoral Imaging Modalities Examine large areas of the dental arches and skull. Study growth and development of bone and teeth. Detect fractures and evaluate trauma. Detect pathological lesions and diseases of the jaws. Detect and evaluate impacted teeth.

10. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Purpose and Use of Extraoral Imaging Modalities Evaluate temporomandibular disorder (TMD). Plan treatment for dental implants and prosthetic appliances.

11. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Figure 29-2 Cephalometric radiograph produced with a filter placed between the tube and patient to remove some of the x- rays to record outlines of the soft tissue profile.

12. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson TABLE 29-1 Extraoral Radiographs of the Maxillofacial Region

13. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson TABLE 29-1 (continued) Extraoral Radiographs of the Maxillofacial Region

14. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson TABLE 29-1 (continued) Extraoral Radiographs of the Maxillofacial Region

15. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson TABLE 29-1 (continued) Extraoral Radiographs of the Maxillofacial Region

16. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Extraoral Image Receptors Traditional film Intensifying screens Cassettes Film identification Care of cassettes and intensifying screens

17. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Figure 29-3 Loading film into a flexible cassette under safelight conditions.

18. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson PROCEDURE 29-1 Loading an extraoral cassette

19. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Figure 29-4 Loading a rigid cassette.

20. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Figure 29-5 Film is placed between the intensifying screens.

21. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Figure 29-6 Static electricity artifacts. Blank area on a panoramic film showing static electricity artifacts.

22. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Figure 29-7 Cross-section of cassette showing the effect of x-ray and fluorescent light on the film. X-ray A strikes a crystal in the screen behind the film, producing light that then forms latent images in the silver halide crystal of the film. X-ray B strikes a silver halide crystal in the film, forming a latent image. X-ray C strikes a crystal in the screen in front of the film, producing light, which then forms latent images in the silver halide crystals of the film.

23. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Figure 29-8 The back side of three rigid cassettes of various sizes.

24. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Figure 29-9 Film identification printer for imprinting permanent identification information on the radiographic image.

25. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Figure 29-10 Grid used to absorb back scattered radiation is placed between the patient and the film to absorb scattered x-rays to reduce film fog.

26. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Figure 29-11 Serial radiographs produced by tomography of the temporomandibular joint showing the head of the condyle in the glenoid fossa with the mouth closed, in the at-rest position, and with the mouth open. (Courtesy of McCormack Dental X-ray Laboratory.)

27. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Figure 29-12 A combination panoramic and TMJ tomography imaging dental x-ray unit. (Courtesy of Planmeca.)

28. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Figure 29-13 CT scanner.

29. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Figure 29-14 Cone beam volumetric imaging machine. Designed for the oral health care practice, can also produce panoramic radiographs. (Courtesy of Gendex Dental Systems/Imaging Sciences Intl.)

30. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Figure 29-15 Image produced by CBCT and reconstructed software. Note the images produced from different planes and the reconstructed 3D image of the teeth in the arches. (Courtesy of Planmeca.)

31. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Review: Chapter Summary Extraoral radiographs image large areas of the head and facial regions. Extraoral screen film is used with a pair of intensifying screens housed in a light-tight cassette. Grids are devices used to absorb scatter radiation that would fog the film and compromise image contrast.

32. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Review: Chapter Summary Radiographs are produced with a stationary x-ray source an image receptor. The practitioner must be skilled in interpreting images obtained by CBCT.

33. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Recall: Study Questions General Chapter Review

34. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Reflect: Case Study Consider the following patients and conditions. Which of the six extraoral radiographs described in this chapter might be the best recommendation for these cases?

35. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Reflect: Case Study (Note: Radiographs of the skull are difficult to interpret due to the numerous structures that exist in a very small area. These structures often appear superimposed over each other, requiring multiple views to obtain a good diagnosis. Therefore, in some of these cases, while there is usually a best answer, there may be more than one correct answer.)

36. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Reflect: Case Study 1. A 20-year-old patient presents with pain and swelling from an impacted third molar. The patient can open only 10 mm. No panoramic unit is available. What is an alternate extraoral projection type that can be used to assess with diagnosis for this patient?

37. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Reflect: Case Study 2. A 13-year-old patient presents for an orthodontic consultation. Occlusal (teeth) and facial disharmonies (soft tissue relationships) need to be assessed prior to treatment intervention.

38. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Reflect: Case Study 3. A difficult extraction case presents with a severely decayed maxillary molar. During the extraction procedure, the root tip fractures and is possibly lost in the sinus cavity. 4. A medically compromised patient suffered a seizure and fell. A fractured mandibular condyle is suspected.

39. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Reflect: Case Study 5. A 69-year-old patient presents with a history of degenerative joint disease that may be affecting the temporal mandibular joint. An examination for the purpose of diagnosing ankylosis (a stiffening of the TMJ) is planned.

40. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Reflect: Case Study 6. A patient presents for extraction of several badly decayed teeth, following which the prosthodontist will construct a maxillary full denture and a mandibular partial denture.

41. Copyright ©2012 by Pearson Education, Inc. All rights reserved. Essentials of Dental Radiography for Dental Assistants and Hygienists, Ninth Edition Evelyn M. Thomson Orlen N. Johnson Relate: Laboratory Application Proceed to Chapter 29, Laboratory Application, to complete this activity.