1. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. Chapter 18 Bisecting Technique

2. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 2 Dental Radiography  Questions  What are the basic principles of the bisecting technique?  What film holders may be used with the bisecting technique?  What are the advantages and disadvantages of the bisecting technique?

3. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 3 Dental Radiography  Chapter 18 Reading:  Iannucci & Howerton (pp. 180-209)

4. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 4 Dental Radiography  Chapter 18 Outline  Bisecting Technique  Basic Concepts  Step-by-Step Procedures  Advantages and Disadvantages

5. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 5 Introduction  Iannucci & Howerton (pp. 180-181)  Purpose  To present basic concepts  To describe patient preparation, equipment preparation, and receptor placement procedures used in the bisecting technique  To describe the advantages and disadvantages of the bisecting technique and review helpful hints

6. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 6 Basic Concepts  Iannucci & Howerton (p. 181)  Bisecting technique  Another method that can be used to expose periapical images

7. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 7 Terminology  Iannucci & Howerton (p. 181) (Fig. 18-1)  Angle  Bisect  Triangle  Triangle, equilateral  Triangle, right

8. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 8 Terminology  Iannucci & Howerton (p. 181) (Figs. 18-1, 18-2)  Triangles, congruent  Hypotenuse  Isometry  Long axis of the tooth  Central ray

9. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 9 Principles of Bisecting Technique  Iannucci & Howerton (pp. 181-182) (Figs. 18-3, 18-4)  Rule of isometry  Two triangles are equal if they have two equal angles and share a common side.

10. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 10 Bisecting Technique  Iannucci & Howerton (pp. 181-182) (Fig. 18-5)  The receptor must be placed along the lingual surface of the tooth.  The plane of the receptor and the long axis of the tooth form an angle at the point where the film contacts the tooth.  Imaginary bisector bisects the angle formed by the receptor and the long axis of the tooth.  The central ray is directed perpendicular to the imaginary bisector.  The two imaginary triangles that result are right triangles and congruent.

11. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 11 Film Stabilization  Iannucci & Howerton (pp. 182-183) (Fig. 18-6)  Beam Alignment Devices  Devices used to position an intraoral receptor  Recommended because they eliminate the need for the patient to stabilize the receptor

12. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 12 Receptors Used in Bisecting Technique  Iannucci & Howerton (p. 183)  Size 2 receptor used traditionally  Anterior Long portion in a vertical direction Long portion in a vertical direction  Posterior Long portion in a horizontal direction Long portion in a horizontal direction

13. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 13 Position-Indicating Device Angulation  Iannucci & Howerton (pp. 183) (Figs. 18-7, 18-8)  Angulation  The alignment of the central ray of the x-ray beam in the horizontal and vertical planes

14. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 14 Horizontal Angulation  Iannucci & Howerton (pp. 183-184) (Figs. 18-9, 18-10)  The positioning of the tubehead and direction of the central ray in a horizontal or side-to- side plane  Correct horizontal angulation The central ray is directed perpendicular to the curvature of the arch and through the contact areas of the teeth. The central ray is directed perpendicular to the curvature of the arch and through the contact areas of the teeth.  Incorrect horizontal angulation Overlapped contact areas Overlapped contact areas

15. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 15 Vertical Angulation  Iannucci & Howerton (pp. 183-185) (Fig. 18-11) (Table 18-1)  The positioning of the PID in a vertical or up- and-down plane  Correct vertical angulation Results in a radiographic image that is the same length as the tooth Results in a radiographic image that is the same length as the tooth  Incorrect vertical angulation Results in a radiographic image that is not the same length as the tooth Results in a radiographic image that is not the same length as the tooth

16. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 16 Vertical Angulation  Iannucci & Howerton (pp. 184-185) (Figs. 18-12, 18-13)  Foreshortened Images  Results from excessive vertical angulation  Elongated images  Results from insufficient vertical angulation

17. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 17 Rules for Bisecting Technique  Iannucci & Howerton (pp. 185-188) (Figs. 18-14, 18-15)  Receptor placement  Receptor position  Vertical angulation  Horizontal angulation

18. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 18 Step-by-Step Procedures  Patient Preparation  Equipment Preparation  Exposure Sequence for Receptor Placements  Receptor Placement for Bisecting Technique

19. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 19 Patient Preparation  Iannucci & Howerton (p. 186)  Infection control procedures  Preparation of treatment area and supplies  Patient is seated  Patient is prepared

20. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 20 Patient Preparation for Bisecting Technique  Iannucci & Howerton (p. 186) (Procedure 18-1)  Explain the radiographic procedure.  Position the patient in the chair.  Adjust the headrest.  Place and secure the lead apron with thyroid collar.  Remove all objects from the patient’s mouth.

21. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 21 Equipment Preparation  Iannucci & Howerton (pp. 186-187) (Procedure 18-2)  Set the exposure factors.  Open the sterilized package containing the beam alignment device if beam alignment devices are used.

22. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 22 Exposure Sequence for Receptor Placements  Iannucci & Howerton (p. 187) (Table 18-2)  Anterior exposure sequence  Begin with the maxillary right canine tooth. Expose all of the maxillary anterior teeth. Expose all of the maxillary anterior teeth. End with the maxillary left canine. End with the maxillary left canine.  Move to the mandibular arch. Begin with the mandibular left canine. Begin with the mandibular left canine. Expose all of the mandibular anterior teeth. Expose all of the mandibular anterior teeth. Finish with the mandibular right canine. Finish with the mandibular right canine.

23. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 23 Exposure Sequence for Receptor Placements  Iannucci & Howerton (pp. 187-188) (Table 18-3)  Posterior exposure sequence  Begin with the maxillary right quadrant.  Move to the mandibular right quadrant.  Move to the maxillary left quadrant.  Finish with the mandibular left quadrant. In each quadrant expose the premolar receptor first and then the molar receptor. In each quadrant expose the premolar receptor first and then the molar receptor.

24. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 24 Receptor Placement for Bisecting Technique  Iannucci & Howerton (pp. 188-189) (Figs. 18-15, 18-16) (Box 18-1, 18-2)  The specific area where the receptor must be positioned before exposure  Dictated by the teeth and surrounding structures that must be included on the resultant radiograph

25. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 25 Receptor Placement for Bisecting Technique  Iannucci & Howerton (pp. 190-197) (Procedures 18-3 through 18-6)  Anterior placement  Maxillary canine exposure  Maxillary incisor exposure  Mandibular canine exposure  Mandibular incisor exposure

26. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 26 Receptor Placement for Bisecting Technique  Iannucci & Howerton (pp. 198-205)  (Procedures 18-7 through 18-10)  Posterior placement  Maxillary premolar exposure  Maxillary molar exposure  Mandibular premolar exposure  Mandibular molar exposure

27. Copyright © 2012, 2006, 2000, 1996 by Saunders, an imprint of Elsevier Inc. 27 Advantages and Disadvantages  Iannucci & Howerton (pp. 189, 206)  Bisecting technique  Advantages Can be used without a beam alignment device Can be used without a beam alignment device  Disadvantages Image distortion Image distortion Angulation problems Angulation problems