Chapter 21

1. Chapter 21 Occlusal and Localization Techniques

2. Dental Radiography • Questions • What are the purposes and uses of an occlusal examination? • What are the correct vertical angulations for maxillary and mandibular occlusal projections? • What is the buccal object rule?

3. Dental Radiography • Chapter 21 Reading • Iannucci & Howerton (pp. 239-255)

4. Dental Radiography • Chapter 21 Outline • Occlusal and Localization Techniques • Occlusal technique • Localization techniques

5. Introduction • Iannucci & Howerton (p. 239) • Purpose • To present basic concepts • To describe patient preparation, equipment preparation, and film placement procedures for both the occlusal and localization techniques

6. Occlusal Technique • Basic Concepts • Terminology • Purpose and use • Principles • Step-by-Step Procedures

7. Occlusal Technique • Used to examine large areas of the upper or lower jaw

8. Terminology • Iannucci & Howerton (pp. 239-240) • Occlusal surfaces • Occlusal examination • Occlusal technique • Occlusal film

9. Purpose and Use • Iannucci & Howerton (p. 240) • A supplementary radiographic technique used in conjunction with periapical or bite-wing images • Used when large areas of the maxilla or mandible must be visualized • Preferred when area of interest is larger than a periapical receptor or when placement of periapical receptors is too difficult for the patient

10. Principles • Iannucci & Howerton (p. 240) • The film is placed with the white side facing the arch to be exposed. • The receptor is placed in the mouth between the occlusal surfaces of the maxillary and mandibular teeth. • The receptor is stabilized when the patient bites on the film.

11. Step-by-Step Procedures • Iannucci & Howerton (pp. 240, 242) • Patient preparation • Equipment preparation • Maxillary occlusal projections • Mandibularocclusal projections • Vertical angulations

12. Patient Preparation • Iannucci & Howerton (p. 240) (Procedure 21-1) • Explain the radiographic procedure to the patient. • Position the patient upright in the chair. • Adjust the headrest to support and position the patient’s head. • Place the lead apron with thyroid collar on the patient and secure it. • Remove all objects from the mouth.

13. Equipment Preparation • Iannucci & Howerton (p. 240) (Procedure 21-2) • Set the exposure factors on the x-ray unit according to the recommendations of the receptor manufacturer. • Either a short (8-inch) or a long (16-inch) position-indicating device (PID) may be used with the occlusal technique.

14. Maxillary Occlusal Projections • Iannucci & Howerton (pp. 240-244) (Figs. 21-1, 21-2, 21-3) (Procedures 21-3, 21-4, 21-5) • Topographic projection • Used to examine the palate and the anterior teeth of the maxilla • Lateral (left or right) projection • Used to examine the palatal roots of the molar teeth • Pediatric projection • Used to examine the anterior teeth of the maxilla, recommended for use in children 5 years old or younger

15. Mandibular Occlusal Projections • Iannucci & Howerton (pp. 242, 245-247) (Figs. 21-4, 21-5, 21-6) (Procedures 21-6, 21-7, 21-8) • Topographic projection • Used to examine the anterior teeth of the mandible • Cross-sectional projection • Used to examine the buccal and lingual aspects of the mandible • Pediatric projection • Used to examine the anterior teeth of the mandible, recommended for use in children 5 years old or younger

16. Vertical Angulations • Iannucci & Howerton (p. 242) (Table 21-1) • Occlusal projection Vertical angulation • Maxillary topographic +65 • Maxillary lateral (rt or lt) +60 • Maxillary pediatric +60 • Mandibular topographic -55 • Mandibular cross-sectional 90 • Mandibular pediatric -55

17. Localization Techniques • Basic Concepts • Purpose and use • Types • Buccal object rule • Right-angle technique • Step-by-Step Procedures

18. Localization Techniques • A method used to locate the position of a tooth or object in the jaws • A thorough understanding of basic concepts is necessary. • A knowledge of step-by-step procedures is required.

19. Purpose and Use • Iannucci & Howerton (p. 242) • The dental radiograph is a two-dimensional picture of a three-dimensional object. • It does not depict the depth of the object. • Localization techniques can be used to locate the object.

20. Buccal Object Rule • Iannucci & Howerton (p. 242) • Governs the orientation of structures portrayed in two radiographs exposed at different angulations • One periapical or bite-wing receptor is exposed using proper technique and angulation. • A second periapical or bite-wing receptor is exposed after changing the direction of the x-ray beam.

21. Buccal Object Rule • Iannucci & Howerton (p. 242, 248) (Figs. 21-7, 21-8) • When the dental structure or object seen in the second radiograph appears to have moved in the same direction as the shift of the PID, the structure or object in question is positioned to the lingual. • When the dental structure or object seen in the second radiograph appears to have moved in the opposite direction as the shift of the PID, the structure or object in question is positioned to the buccal.

22. Buccal Object Rule • A mnemonic - SLOB • S = same • L = lingual • O = opposite • B = buccal

23. Right-Angle Technique • Iannucci & Howerton (pp.248-249) (Fig. 21-9) • Another rule for the orientation of structures seen on images • One periapical receptor is exposed using the proper technique and angulation to show the position of an object in the superior-inferior and anterior-posterior relationship. • An occlusal receptor is exposed directing the central ray perpendicular to the film. • The images are compared to locate the object in three dimensions.

24. Step-by-Step Procedures • Iannucci & Howerton (pp. 248-252) (Figs. 21-10, 21-11, 21-12, 21-13) • Patient and equipment preparations • Receptor placements and comparisons • Buccal object rule • Right-angle technique