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(BQ) Part 1 book “Essentials of dental radiography for dental assistants and hygienists” has contents: Historical perspective and radiation basics, biological effects of radiation and radiation protection, dental x-ray image receptors and film processing techniques, dental radiographer fundamentals, intraoral techniques.
This page intentionally left blank Essentials of Dental Radiography for Dental Assistants and Hygienists This page intentionally left blank Essentials of Dental Radiography for Dental Assistants and Hygienists N I N T H E D I T I O N Evelyn M Thomson, BSDH, MS Adjunct Assistant Professor Gene W Hirschfeld School of Dental Hygiene Old Dominion University Norfolk, Virginia Orlen N Johnson, BS, DDS, MS College of Dentistry University of Nebraska Medical Center Lincoln, Nebraska Pearson Boston Columbus Indianapolis New York San Francisco Upper Saddle River Amsterdam Cape Town Dubai London Madrid Milan Munich Paris Montreal Toronto Delhi Mexico City Sao Paulo Sydney Hong Kong Seoul Singapore Taipei Tokyo Library of Congress Cataloging-in-Publication Data Cataloging-in-Publication data on file with the Library of Congress Notice: The authors and the publisher of this volume have taken care that the information and technical recommendations contained herein are based on research and expert consultation and are accurate and compatible with the standards generally accepted at the time of publication Nevertheless, as new information becomes available, changes in clinical and technical practices become necessary The reader is advised to carefully consult manufacturers’ instructions and information material for all supplies and equipment before use and to consult with a health care professional as necessary This advice is especially important when using new supplies or equipment for clinical purposes The authors and publisher disclaim all responsibility for any liability, loss, injury, or damage incurred as a consequence, directly or indirectly, of the use and application of any of the contents of this volume Publisher: Julie Levin Alexander Assistant to Publisher: Regina Bruno Editor-in-Chief: Mark Cohen Executive Editor: John Goucher Development Editor: Melissa Kerian Assistant Editor: Nicole Ragonese Editorial Assistant: Rosalie Hawley Media Editor: Amy Peltier Media Product Manager: Lorena Cerisano Managing Production Editor: Patrick Walsh Production Liaison: Christina Zingone Production Editor: Sunitha Arun Bhaskar, Laserwords Manufacturing Manager: Alan Fischer Design Director: Jayne Conte Cover Designer: Suzanne Behnke Director of Marketing: David Gesell Executive Marketing Manager: Katrin Beacom Marketing Specialist: Michael Sirinides Composition: Laserwords Printer/Binder: Edwards Brothers Cover Printer: Lehigh-Phoenix Color/Hagerstown Cover Image: Dental X-Rays, Ocean Photography/Veer Copyright © 2012, 2007, 2003 Pearson Education, Inc., Lake Street, Upper Saddle River, New Jersey 07458 Publishing as Pearson All rights reserved Manufactured in the United States of America This publication is protected by Copyright, and permission should be obtained from the publisher prior to any prohibited reproduction, storage in a retrieval system, or transmission in any form or by any means, electronic, mechanical, photocopying, recording, or likewise To obtain permission(s) to use material from this work, please submit a written request to Pearson Education, Inc., Permissions Department, Lake Street, Upper Saddle River, New Jersey 07458 10 www.pearsonhighered.com ISBN-13: 978-0-13-801939-6 ISBN-10: 0-13-801939-8 To my husband, Hu Odom, once again your loving patience, support, and encouragement gets me through —Evie This page intentionally left blank Contents Preface ix Acknowledgments Reviewers xi xii PART I: Historical Perspective and Radiation Basics Chapter History of Dental Radiography Chapter Characteristics and Measurement of Radiation Chapter The Dental X-ray Machine: Components and Functions 20 Chapter Producing Quality Radiographs 1 32 PART II: Biological Effects of Radiation and Radiation Protection Chapter Effects of Radiation Exposure Chapter Radiation Protection 47 47 57 PART III: Dental X-ray Image Receptors and Film Processing Techniques 74 Chapter Dental X-ray Film 74 Chapter Dental X-ray Film Processing Chapter Digital Radiography 83 97 PART IV: Dental Radiographer Fundamentals Chapter 10 Infection Control Chapter 11 Legal and Ethical Responsibilities Chapter 12 Patient Relations and Education PART V: Intraoral Techniques 114 114 131 138 147 Chapter 13 Intraoral Radiographic Procedures 147 Chapter 14 The Periapical Examination—Paralleling Technique Chapter 15 The Periapical Examination—Bisecting Technique Chapter 16 The Bitewing Examination Chapter 17 The Occlusal Examination 161 179 196 215 vii viii CONTENTS PART VI: Radiographic Errors and Quality Assurance 227 Chapter 18 Identifying and Correcting Undiagnostic Radiographs Chapter 19 Quality Assurance in Dental Radiography Chapter 20 Safety and Environmental Responsibilities in Dental Radiography 251 241 PART VII: Mounting and Viewing Dental Radiographs 264 Chapter 21 Mounting and Introduction to Interpretation Chapter 22 Recognizing Normal Radiographic Anatomy Chapter 23 Recognizing Deviations from Normal Radiographic Anatomy 289 Chapter 24 The Use of Radiographs in the Detection of Dental Caries 303 Chapter 25 The Use of Radiographs in the Evaluation of Periodontal Diseases 314 264 273 PART VIII: Patient Management and Supplemental Techniques Chapter 26 Radiographic Techniques for Children Chapter 27 Managing Patients with Special Needs Chapter 28 Supplemental Radiographic Techniques PART IX: Extraoral Techniques 325 340 350 364 Chapter 29 Extraoral Radiography and Alternate Imaging Modalities 364 Chapter 30 Panoramic Radiography Answers to Study Questions Glossary Index 407 423 403 377 227 325 212 INTRAORAL TECHNIQUES REVIEW—Chapter summary Bitewing radiographs image the coronal portion of both maxillary and mandibular teeth on one image receptor Bitewing radiographs supplement and complete the full mouth survey because of their improved ability to image incipient caries in the tooth contact areas and early resorptive changes in the alveolar bony crest The size and number of images to expose depend on the type of survey required and the size and shape of the patient’s oral cavity The image receptor may be positioned with the long dimension horizontally or vertically Traditionally posterior bitewing radiographs have been positioned horizontally Anterior bitewing radiographs are positioned vertically Vertical positioning in the posterior regions image more periodontal bone The patient’s occlusal relationship should be used to determine which arch the radiographer should focus on during placement of the image receptor Positioning the image receptor a slight distance away from the lingual surfaces of the maxillary teeth of interest will help avoid contact with the curvature of the palate and avoid producing a sloping or slanted image that may result in a retake Using a systemic order of sequence in exposing bitewing radiographs will help avoid errors Image receptor holders/positioners include stick-on or loop bitetabs and instruments with external aiming devices that assist with determining the correct horizontal and vertical angulations and the points of entry If a holder without an external aiming device is used, the horizontal angulation is determined by directing the central ray of the x-beam perpendicular to the recording plane of the image receptor through the mean tangent of the embrasures between the teeth of interest, and the vertical angulation for all bitewing radiographs is +10 degrees When the horizontal angulation is directed obliquely from the mesial, overlapping will be more severe in the distal or posterior region of the image; when the horizontal angulation is directed obliquely from the distal, overlapping will be more severe in the mesial or anterior region of the image When the vertical angulation is excessive (greater than +10°), more maxillary teeth and bone are imaged, cutting off a portion of the mandibular structures When the vertical angulation is inadequate (less than +10°) more mandibular teeth and bone are imaged, cutting off a portion of the maxillary structures Directing the central ray of the x-ray beam at the level of the incisal/occlusal plane (at the lip line) will assist with directing the central ray of the x-ray beam to the center of the image receptor to avoid conecut error The four basic steps to exposing a bitewing radiograph are placement, vertical angulation, horizontal angulation, and point of entry Step-by-step illustrated instructions for exposing anterior and posterior bitewing radiographs are presented RECALL—Study questions Which of these conditions would NOT be visible on a bitewing radiograph? a Proximal surface caries b Overhanging restoration c Apical abscess d Alveolar crest resorption How many standard-sized #2 image receptors are recommended for a posterior horizontal bitewing survey of an adult patient? a b c d In which of the following situations would using a size #3 image receptor be acceptable? a Horizontal bitewings on a child patient who presented a need for them b Horizontal bitewings on an adult patient for caries detection c Horizontal bitewings on an adult patient with periodontal disease d Vertical bitewings on any patient who presented with a need for them In which of the following conditions would vertical bitewing radiographs be recommended over horizontal bitewing radiographs? a Child with rampant caries b Adolescent with suspected third molar impactions c Adult with malaligned teeth d Adult with periodontal disease Which size image receptor is used, and how is it positioned for exposure of an anterior bitewing radiograph of a small and narrow adult arch? a Size #3 placed vertically b Size #2 placed horizontally c Size #1 placed vertically d Size #0 placed horizontally When taking a premolar horizontal bitewing radiograph, the anterior edge of the image receptor should be positioned behind the distal edge of the maxillary canine when presented with which occlusal relationship? a Class I b Class II c Class III When taking a set of eight vertical bitewing radiographs, which of the following should be exposed first? a Left molar bitewing b Left premolar bitewing c Right canine bitewing d Right premolar bitewing Which of the following best fits this description: “Disposable, may be used for placing both horizontal and vertical bitewings, and provides increased imaging of the alveolar bone”? a Stick-on bitetabs b Manufacturer preattached bitetabs c Bite loops d Holder with external aiming device CHAPTER 16 • THE BITEWING EXAMINATION An error in which of these results in overlapping? a Placement of image receptor b Point of entry c Vertical angulation d Horizontal angulation 10 What is the approximate vertical angulation for adult bitewing radiographs? a -10 degrees b degrees c +10 degrees d +20 degrees 11 An error in vertical angulation will result in a unequal distribution of the arches b overlapping c overexposure to the patient d conecut 12 The image receptor placement for an adult horizontal molar bitewing is to align the receptor so that the a central and lateral incisors are centered b canine is centered c anterior portion of the receptor lines up behind the distal half of the canine d anterior portion of the receptor lines up behind the distal half of the second premolar 13 The image receptor placement for an adult vertical premolar bitewing is to align the receptor so that the a central and lateral incisors are centered b canine is centered c anterior portion of the receptor lines up behind the distal half of the canine d anterior portion of the receptor lines up behind the distal half of the second premolar Case: Age/Gender: Medical History: Dental History: New patient to your practice 40-year-old male Hypertension Has had extensive dental treatment in the past as evidenced by several extractions and restored teeth 14 Through which interproximal space should the central ray of the x-ray beam be perpendicularly directed when exposing a molar bitewing on a child with primary teeth? a Between the central and lateral incisors b Between the lateral incisor and canine c Between the canine and first molar d Between the first and second molars 15 Through which interproximal space should the central ray of the x-ray beam be perpendicularly directed when exposing a premolar bitewing on an adolescent with permanent teeth? a Between the central and lateral incisors b Between the lateral incisor and canine c Between the canine and first premolar d Between the first and second premolars REFLECT—Case study Study the dental chart and patient record that follows Note the dentist’s written prescription for a radiographic examination Decide the following: What type of bitewings will most likely be exposed? What size image receptor will best fit this patient? How many image receptors will be required to complete the exam? Write out a detailed procedure for exposing each of the required radiographs Include: a Specific image receptor placements b The vertical angulation required c How the horizontal angulation will be determined d What the point of entry will be Social History: Chief Complaint: Current Oral Hygiene Status: Initial Treatment: Appears nervous of dental treatment Thinks he has “gum disease.” Generalized 4–6 mm pockets; Generalized moderate gingivitis Take a set of bitewing radiographs Probe R Clinically visible restoration Probe Probe Clinically visible carious lesion R Clinically missing tooth Probe 213 214 INTRAORAL TECHNIQUES RELATE—Laboratory application For a comprehensive laboratory practice exercise on this topic, see Thomson, E M (2012) Exercises in oral radiography techniques: A laboratory manual (3rd ed.) Upper Saddle River, NJ: Pearson Chapter 2, “Bitewing radiographic technique.” REFERENCES Eastman Kodak Company (2002) Successful intraoral radiography Rochester, NY: Author Rinn Corporation (1989) Intraoral radiography with Rinn XCP/BAI instruments Elgin, IL: Dentsply/Rinn Corporation White, S C., & Pharoah, M J (2008) Oral radiology: Principles and interpretation (6th ed.) St Louis, MO: Elsevier Wilkins, E M (2010) Clinical practice of the dental hygienist (10th ed.) Philadelphia: Lippincott Williams & Wilkins CHAPTER The Occlusal Examination OBJECTIVES Following successful completion of this chapter, you should be able to: 17 CHAPTER OUTLINE Define the key words State the purpose of the occlusal examination List the indications for occlusal radiographs Match the topographical and cross-sectional techniques with the condition to be imaged Compare the patient head positions for the topographical and the cross-sectional techniques Demonstrate the steps for the maxillary and mandibular topographical surveys Demonstrate the steps for the mandibular cross-sectional survey KEY WORDS Cross-sectional technique Occlusal radiograph Topographical technique ᭤ Objectives ᭤ Key Words ᭤ Introduction ᭤ Types of Occlusal Examinations ᭤ Fundamentals of Occlusal Radiographs ᭤ Horizontal and Vertical Angulation Procedures ᭤ Points of Entry ᭤ The Occlusal Examination ᭤ Review, Recall, Reflect, Relate ᭤ References 215 215 216 216 216 217 218 219 225 226 216 INTRAORAL TECHNIQUES Cross-sectional Technique Introduction The purpose of the occlusal examination is to view large areas of the maxilla (upper jaw) or the mandible (lower jaw) on one radiograph The image receptor is placed in the mouth between the occlusal surfaces of the maxillary and mandibular teeth The patient occludes (bites) lightly on the image receptor to stabilize it The purpose of this chapter is to discuss the use and explain the procedures for the occlusal examination The cross-sectional technique produces an image much like its name implies (Figure 17-1) The circular or elliptical appearance of the teeth on the radiograph and the increased coverage of the sublingual area (under the tongue) allow the cross-sectional occlusal radiograph to yield more information about the location of tori and impacted or malpositioned teeth and calcifications of soft tissues Fundamentals of Occlusal Radiographs Types of Occlusal Examinations Occlusal radiographs are either topographical or cross-sectional Topographical Technique The topographical technique produces an image that looks like a large periapical radiograph (Figure 17-1) The topographical occlusal technique is similar to the bisecting technique used to produce periapical radiographs (see Chapter 15) Topographical occlusal radiographs may be exposed in any area of the oral cavity, the anterior and posterior regions of both the maxilla and the mandible Topographical occlusal radiographs are best used to image conditions of the teeth and supporting structures when a larger area than that imaged by a periapical radiograph is required Topographical occlusal surveys generally yield a greater amount of information in the alveolar crest and apical areas than periapical radiographs A The occlusal examination may be made alone or to supplement periapical or bitewing radiographs The large size #4 occlusal image receptor is useful for recording information that cannot be adequately recorded on the smaller periapical image receptors Occlusal radiographs are used to: • Locate supernumerary, unerupted, or impacted teeth (especially impacted canines and third molars) • Locate retained roots of extracted teeth • Detect the presence, locate, and evaluate the extent of disease and lesions (cysts, tumors, etc.) • Locate foreign bodies in the jaws • Reveal the presence of salivary stones (sialoliths) in the ducts of the sublingual and submandibular glands • Aid in evaluating fractures of the maxilla or mandible • Show the size and shape of mandibular tori B FIGURE 17-1 A comparison of topographical and cross-sectional occlusal radiographs (A) The topographical occlusal radiograph of the anterior mandible closely resembles a periapical radiograph Note how the large occlusal film images a larger portion of the region (B) The cross-sectional occlusal radiograph of the mandibular anterior region reveals more information about the sublingual area (under the tongue) and conditions of the soft tissue than about the teeth and the supporting bone CHAPTER 17 • THE OCCLUSAL EXAMINATION • Aid in examining patients with trismus who can open their mouths only a few millimeters • Evaluate the borders of the maxillary sinus • Examine cleft palate patients • Substitute for a periapical examination on young children who may not be able to tolerate periapical image receptor placement (see Chapter 26) Occlusal radiographs may be taken in any region of the oral cavity This chapter focuses on five of the most common standard placements: Maxillary topographical (anterior) Maxillary topographical (posterior) Mandibular topographical (anterior) Mandibular topographical (posterior) Mandibular cross-sectional Image Receptor Requirements The large * 1/4 in 17.7 * 5.8 cm2 #4 film or phosphor plate is used for occlusal radiographs on most adult patients Currently this larger size #4 is not available as a digital sensor Smaller size #2 intraoral image receptors may also be used, depending on the area to be examined The standard #2 periapical film or sensor is frequently used with children, either to image labiolingual or buccolingual unerupted tooth positions or in place of periapical radiographs when needed Orientation of the Image Receptor An image receptor holder is not used for occlusal radiographs The image receptor is held in place during the exposure by slight pressure of the teeth of the opposite jaw When using a size #4 film, the packet is positioned with the white unprinted side (front side) against the arch of interest When using a phosphor plate, the plain side is positioned against the arch of interest When imaging the mandibular arch, the white, unprinted side of the image receptor will face the mandible When imaging the maxillary arch, the white, unprinted side of the image receptor will face the maxilla The image receptor may be placed into the mouth with the long dimension positioned horizontally or vertically, centered over one small region of interest or over the entire right or left sides of the dental arches The position used will depend on the type of occlusal radiograph needed and the area to be imaged In the correct position, the image receptor should be placed well back into the mouth, but with at least 1/4 in (1/2 cm) protruding outside the mouth to avoid cutting off part of the image Because the embossed identification dot (on the film packet) should be positioned away from the area of interest, positioning it toward the anterior should leave it outside the mouth and therefore prevent it from interfering with the image Patient Positioning Because predetermined vertical angulations and points of entry are utilized in taking occlusal radiographs (just as 217 they are for periapical radiographs using the bisecting technique), it is very important that the patient be seated with the head in the correct position for the area to be imaged For occlusal radiographs taken on the maxilla, the patient should be seated with the occlusal plane parallel to the plane of the floor and the midsagittal plane perpendicular to the plane of the floor (see Figure 13-14) The head position for the mandibular exposures will depend on the type of occlusal radiograph to be produced Topographical occlusal radiographs of the mandible may be taken with the head positioned the same as for maxillary exposures, with the occlusal plane parallel to the floor and the midsagittal plane perpendicular to the floor Mandibular cross-sectional occlusal radiographs are taken with the patient reclined in the chair so that the head is tipped back, positioning the occlusal plane perpendicular to the plane of the floor (Figure 17-2) Exposure Factors The exposure factors (kVp, mA, and time) used for occlusal radiographs are usually the same as those settings used for periapical and bitewing radiographs of the same region Horizontal and Vertical Angulation Procedures Horizontal Angulation The correct horizontal angulation for topographical occlusal radiographs is determined in the same manner as for periapical and bitewing radiographs; by directing the central rays at the image receptor perpendicularly through the teeth embrasures (spaces) When exposing anterior topographical occlusal radiographs, direct the central rays of the x-ray beam perpendicular to the image receptor through the interproximal embrasures of the anterior teeth When exposing posterior topographical occlusal radiographs, direct the central rays of the x-ray beam perpendicular to the image receptor through Image receptor X-ray unit Floor FIGURE 17-2 Patient positioning for mandibular crosssectional occlusal radiographs Patient reclined in the chair so that the head is tipped back, positioning the occlusal plane perpendicular to the plane of the floor The central rays of the x-ray beam are directed toward the image receptor perpendicularly INTRAORAL TECHNIQUES Vertical Angulation If the patient’s head is in the correct position, predetermined points of entry may be used (Table 17-2) Essentially, the central rays of the x-ray beam should strike the middle of the image receptor The open end of the PID must be aligned as close as possible to the patient’s skin at the correct point of entry Although occlusal radiographs can be made with any length position indicating device (PID), the shorter 8-in (20.5-cm) length may be easier to position into the increased vertical angulation positions required for this technique In addition, because of the angular relationship between the object (teeth) and the central ray of the x-ray beam, a longer PID length (16-in./41-cm) will likely add to the dimensional distortion of the image y al 90° Image receptor r cto le 90° e s Bi ang of y Points of Entry Bi of sec an tor gle al ntr Ce The vertical angulation for topographical occlusal radiographs follows the rules of the bisecting technique used for periapical radiographs, where the central rays of the x-ray beam are directed through the apices of the teeth perpendicularly toward the bisector (Figure 17-3) To determine the correct vertical angulation when taking a topographical occlusal radiograph, the radiographer must observe the plane of the image receptor, locate the long axes of the teeth of interest, and estimate the imaginary bisector of these two planes If the patient’s head is in the correct position, the radiographer can use predetermined vertical angulation settings (Table 17-1) The vertical angulation for the mandibular cross-sectional occlusal radiograph of the mandible is such that the central rays of the x-ray beam are directed toward the image receptor perpendicularly (Figure 17-2) To achieve a perpendicular relationship between the plane of the image receptor and the central rays of the x-ray beam, the patient’s head position must be such that the occlusal plane is perpendicular to the plane of the floor In other words, the patient should be reclined and the chin tipped upward In this position, the vertical angulation will most likely be set at 0º, allowing the x-rays to strike the image receptor perpendicularly Cross-sectional occlusal radiographs of the maxilla are sometimes needed to assess the maxillary sinus, edentulous ridges, or other specific needs However, the significant amount of bony structures located here make cross-sectional occlusal radiographs of the maxilla difficult to image with clarity Therefore maxillary cross-sectional occlusal radiographs are exposed less frequently A n tr the interproximal spaces or embrasures of the posterior teeth The horizontal angulation for the mandibular cross-sectional is also such that the central rays will intersect the image receptor perpendicularly This alignment is best determined by positioning the open end of the PID parallel to the image receptor Ce 218 B FIGURE 17-3 Angulation theory of topographical occlusal radiographs The image receptor placement for occlusal radiographs is not parallel to the long axes of the teeth being imaged Based on the bisecting technique, vertical angulation for (A) maxillary and (B) mandibular topographical radiographs is determined by directing the central rays of the x-ray beam perpendicular to the imaginary bisector between the plane of the image receptor and the long axes of the teeth of interest PRACTICE POINT When exposing an occlusal radiograph on the mandible, it may be necessary to modify placement of the lead/lead equivalent thyroid collar Although it is very important to use ALARA (as low as reasonably achievable) practices and use the lead/lead equivalent thyroid collar to protect radiation-sensitive tissues in the head and neck region, the thyroid collar may be in the path of the primary beam during mandibular topographical and/or cross-sectional techniques You should place the lead/lead equivalent apron and thyroid collar on the patient in the usual manner After adjusting the patient’s head position and placing the image receptor, align the PID and check to be sure that the thyroid collar is not in the path of the x-ray beam If the thyroid collar is in a position that will block the x-rays from reaching the image receptor, adjust the collar position Failure to remove the thyroid collar from in front of the open end of the PID will most likely result in a retake of the radiograph CHAPTER 17 • THE OCCLUSAL EXAMINATION TABLE 17-1 Recommended Vertical Angulation Settings for Occlusal Radiographs OCCLUSAL RADIOGRAPH VERTICAL ANGLE SETTING* +65° Maxillary topographical (anterior) Maxillary topographical (posterior) 219 The Occlusal Examination Figures 17-4 through 17-8 illustrate the image receptor positions and required angulations for each of the topographical and cross-sectional occlusal radiographs discussed in this chapter See Table 17-2 for a summary of the technique +45° Mandibular topographical (anterior) -55° Mandibular topographical (posterior) -45° Mandibular cross-sectional 0°** *The patient must be seated in the correct position, with the occlusal plane of the arch being imaged parallel to the floor and the midsaggital plane perpendicular to the floor **The patient must be seated in the correct position, with the occlusal plane of the mandible perpendicular to the floor and the midsaggital plane parallel to the floor TABLE 17-2 A Summary of Occlusal Radiographic Technique OCCLUSAL RADIOGRAPH Maxillary topographical (anterior) (Figure 17-4) PLACEMENT HORIZONTAL ANGULATION Long dimension across the Perpendicular to the imaginary Perpendicular to the mouth (buccal-to-buccal) bisector between the long image receptor White unprinted film side axes of the teeth and image through the maxiltoward the maxillary receptor in the vertical lary central incisor teeth dimension, +65° embrasure Maxillary topographical Long dimension along the (posterior) (Figure 17-5) midline (front-to-back) White unprinted film side toward the maxillary teeth Mandibular topographical (anterior) (Figure 17-6) VERTICAL ANGULATION* Perpendicular to the imaginary Perpendicular to the bisector between the long image receptor axes of the teeth and the through the image receptor in the vertical maxillary posterior dimension, +45° embrasures Long dimension across Perpendicular to the imaginary Perpendicular to the the mouth (buccal-tobisector between the long image receptor buccal) White unprinted axes of the teeth and the through the film side toward the image receptor in the vertical mandibular central mandibular teeth dimension, -55° incisor embrasure Mandibular topographical Long dimension along the (posterior) (Figure 17-7) midline (front-to-back) White unprinted film side toward the mandibular teeth POINT OF ENTRY* Through a point near the bridge of the nose toward the center of the image receptor Through a point on the ala–tragus line below the outer cantus of the eye (see Figure 15-7) toward the center of the image receptor Through a point on the middle of the chin toward the center of the image receptor Perpendicular to the imaginary Perpendicular to the Through a point on the bisector between the long image receptor inferior border of the axes of the teeth and the through the mandible directly image receptor in the vertical mandibular posterior below the second dimension, -45° embrasures mandibular premolar toward the center of the image receptor Mandibular cross-sectional Long dimension across the Perpendicular to the image (Figure 17-8) mouth (buccal-toreceptor; 0°.** buccal) White unprinted side toward the mandibular teeth Align the open end of the PID parallel to the plane of the image receptor Through a point in (5 cm) back from the tip of the chin toward the center of the image receptor** *The patient must be seated in the correct position, with the occlusal plane of the arch being imaged parallel to the floor and the midsaggital plane perpendicular to the floor **The patient must be seated in the correct position, with the occlusal plane of the mandible perpendicular to the floor and the midsaggital plane parallel to the floor 220 INTRAORAL TECHNIQUES OCCLUSAL TECHNIQUE Maxillary Topographical Occlusal Radiograph (Anterior) PID Tube head 65° A B C FIGURE 17-4 Maxillary topographical occlusal radiograph (anterior) (A) Diagram showing relationship of tube head and PID to image receptor and patient Exposure side of the image receptor faces the maxillary arch with longer dimension buccal-to-buccal (across the arch) The central ray is directed perpendicular in the horizontal dimension to the patient’s midsagittal plane through the maxillary central incisor embrasure The vertical angulation is directed approximately +65° through a point near the bridge of the nose toward the center of the image receptor (B) Patient showing position of image receptor and 8-in (20.5-cm) circular PID (C) Anterior maxillary topographical occlusal radiograph CHAPTER 17 • THE OCCLUSAL EXAMINATION 221 OCCLUSAL TECHNIQUE Maxillary Topographical Occlusal Radiograph (Posterior) Tube head D PI 45° A B C FIGURE 17-5 Maxillary topographical occlusal radiograph (posterior) (A) Diagram showing relationship of tube head and PID to image receptor and patient The image receptor is positioned over the left or right side, depending on the area of interest Exposure side of the image receptor faces the maxillary arch with longer dimension along the midline (anterior-to-posterior) The central ray is directed perpendicular in the horizontal dimension to patient’s midsagittal plane through the maxillary posterior embrasures The vertical angulation is directed approximately +45° through a point on the ala–tragus line below the outer canthus of the eye toward the center of the image receptor (B) Patient showing position of image receptor and 8-in (20.5-cm) circular PID (C) Posterior maxillary topographical occlusal radiograph 222 INTRAORAL TECHNIQUES OCCLUSAL TECHNIQUE Mandibular Topographical Occlusal Radiograph (Anterior) −55° D PI Tube head A B C FIGURE 17-6 Mandibular topographical occlusal radiograph (anterior) (A) Diagram showing relationship of tube head and PID to image receptor and patient Exposure side of the image receptor faces the mandibular arch with longer dimension buccal-to-buccal (across the arch) The central ray is directed perpendicular in the horizontal dimension to patient’s midsaggittal plane through the mandibular central incisor embrasure The vertical angulation is directed approximately - 55° through a point in the middle of the chin toward the center of the image receptor (B) Patient showing position of image receptor and 8-in (20.5-cm) circular PID (C) Anterior mandibular topographical occlusal radiograph CHAPTER 17 • THE OCCLUSAL EXAMINATION 223 OCCLUSAL TECHNIQUE Mandibular Topographical Occlusal Radiograph (Posterior) −45° PI D Tube head A B C FIGURE 17-7 Mandibular topographical occlusal radiograph (posterior) (A) Diagram showing relationship of tube head and PID to image receptor and patient The image receptor is positioned over the left or right side, depending on the area of interest Exposure side of the image receptor faces the mandibular arch with longer dimension along the midline (anterior-to-posterior) The central ray is directed perpendicular in the horizontal dimension to patient’s midsagittal plane through the mandibular posterior embrasures The vertical angulation is directed approximately -45° through a point on the inferior border of the mandible directly below the second mandibular premolar toward the center of the image receptor (B) Patient showing position of image receptor and 8-in (20.5-cm) circular PID (C) Posterior mandibular topographical occlusal radiograph 224 INTRAORAL TECHNIQUES OCCLUSAL TECHNIQUE PID Tube head Mandibular Cross-Sectional Occlusal Radiograph A B C FIGURE 17-8 Mandibular cross-sectional occlusal radiograph (A) Diagram showing relationship of tube head and PID to image receptor and patient The exposure side of the image receptor faces the mandibular arch with the longer dimension buccal-to-buccal (across the arch) The central ray is directed perpendicular in both the horizontal and vertical dimensions toward the image receptor Positioning the open end of the PID parallel to the image receptor achieves the required perpendicular alignment The vertical angulation is directed approximately 0º through a point in (5 cm) back from the tip of the chin toward the center of the image receptor (B) Patient showing position of image receptor and 8-in (20.5-cm) circular PID (C) Mandibular cross-sectional occlusal radiograph CHAPTER 17 • THE OCCLUSAL EXAMINATION REVIEW—Chapter summary The purpose of occlusal radiographs is to image a larger area than that produced on a periapical radiograph The topographical occlusal teachnique is based on a modification of the bisecting technique used to expose periapical radiographs The x-ray beam is directed perpendicularly toward the image receptor in both the horizontal and vertical dimensions when exposing a cross-sectional occlusal radiograph Occlusal radiographs are used to view conditions of the teeth and supporting structures such as impactions, large apical lesions, calcifications in soft tissue, and fractures Size #4 image receptor is used for adult examinations If indicated, a size #2 or smaller image receptor may be used with the occlusal technique, especially for children An image receptor holder is not required; the patient lightly bites down on the image receptor to hold it in place The image receptor may be positioned with the long dimension horizontal or vertical with at least 1/4 in (1/2 cm) protruding outside the mouth The patient’s head should be positioned with the occlusal plane parallel and the midsaggital plane perpendicular to the floor when exposing maxillary and mandibular topographical occlusal radiographs The patient’s head should be tipped back into a position with the occlusal plane perpendicular to the plane of the floor and the midsaggital plane parallel to the floor when exposing a mandibular cross-sectional occlusal radiograph The horizontal angulation used to produce a topographical occlusal radiograph is determined in the same manner as for periapical and bitewing radiographs, where the central rays of the x-ray beam are directed perpendicularly to the image receptor through the embrasures of the teeth of interest Aligning the open end of the PID parallel to the image receptor will assist in determining the correct horizontal angulation to produce a cross-sectional occlusal radiograph The vertical angulation used to produce a topographical occlusal radiograph is determined in a similar manner to the bisecting technique used to produce periapical radiographs, where the central rays of the x-ray beam are directed perpendicularly to the bisector between the long axes of the teeth and the plane of the image receptor Determining the vertical angulation for exposure of a cross-sectional occlusal radiograph is assisted by positioning the open end of the PID parallel to the plane of the image receptor Correct points of entry position are determined by directing the central rays of the x-ray beam at the center of the image receptor If the patient’s head is in correct position, predetermined vertical angulations and points of the entry may be used Step-by-step illustrated instructions for exposing five of the most common occlusal radiographs are presented RECALL—Study questions Each of the following is an indication for exposing occlusal radiographs EXCEPT one Which one is the EXCEPTION? a Evaluate periodontal disease b Examine sinus borders c Locate foreign bodies d Reveal sialoliths 225 Which of the following will a mandibular cross-sectional occlusal radiograph best image? a b c d Cleft palate Fractured jaw Large periapical cyst Sublingual swelling Which of these sizes is known as the occlusal image receptor? a b c d #1 #2 #3 #4 The image receptor should be placed with the long dimension along the midline (front to back) for which of these occlusal radiographs? a b c d Maxillary topographical anterior Maxillary topographical posterior Mandibular topographical anterior Mandibular cross-sectional Where should the embossed dot be positioned when placing an occlusal film packet intraorally? a b c d Toward the apical Toward the occlusal Toward the anterior Toward the posterior The ideal patient head position when exposing a maxillary topographical occlusal radiograph is to position the occlusal plane to the plane of the floor and the midsaggital plane to the plane of the floor a b c d parallel; perpendicular perpendicular; parallel parallel; parallel perpendicular; perpendicular The ideal patient head position when exposing a mandibular cross-sectional occlusal radiograph is to position the head rest so that the chin is tipped and the occlusal plane is to the plane of the floor a b c d down; perpendicular up; perpendicular down; parallel up; parallel Assuming that the patient’s head is in the correct position, which of the following is the correct vertical angulation setting for a maxillary anterior topographical occlusal radiograph? a b c d +65 degrees +45 degrees degrees -55 degrees 226 INTRAORAL TECHNIQUES Assuming that the patient’s head is in the correct position, which of the following is the correct vertical angulation setting for a mandibular cross-sectional occlusal radiograph? a +65 degrees b +45 degrees c degrees d -55 degrees 10 What is the point of entry for correctly exposing a posterior mandible topographical occlusal radiograph? a The middle of the chin b A point in (5 cm) back from the tip of the chin c A point on the ala–tragus line below the outer cantus of the eye d A point on the inferior border of the mandible directly below the second mandibular premolar An adult patient presents with severe pain in the mandibular left posterior region, indicating the possibility of an impacted third molar The pain and swelling in this region is preventing the patient from opening more than a few millimeters What type of occlusal radiograph will this patient most likely be assessed for? A child patient presents with trauma to the maxillary anterior teeth after a fall off her bicycle What type of occlusal radiograph will this patient most likely be assessed for? RELATE—Laboratory application For a comprehensive laboratory practice exercise on this topic, see Thomson, E M (2012) Exercises in oral radiography techniques: A laboratory manual (3rd ed.) Upper Saddle River, NJ: Pearson Education Chapter 10 “Occlusal Radiographic Technique.” REFLECT—Case study Consider the following cases After determining the radiographic assessment for each of these three cases, write out a detailed procedure chart that a radiographer can follow to obtain the needed radiographs Begin with patient positioning Be sure to include the steps for determining the correct placement of the image receptor, x-ray beam angles, and landmarks for determining points of entry An adult patient presents with a sublingual swelling indicating the possibility of a blocked salivary gland What type of occlusal radiograph will this patient most likely be assessed for? REFERENCES Carroll, M K (1993) Advanced oral radiographic techniques: Part I, occlusal and lateral oblique projections (videorecording) Jackson, MS: Health Sciences Consortium, Learning Resources, University of Mississippi Medical Center Eastman Kodak Company (2002) Successful intraoral radiography Rochester, NY: Author White, S C., & Pharoah, M J (2008) Oral radiology: Principles and interpretation (6th ed.) St Louis, MO: Elsevier ... intentionally left blank Essentials of Dental Radiography for Dental Assistants and Hygienists This page intentionally left blank Essentials of Dental Radiography for Dental Assistants and Hygienists N I... the first digital imaging system called RadioVisioGraphy 18 95 18 96 18 96 18 96 19 01 1896 19 04 19 07 19 13 19 13 19 24 19 20 19 47 19 87 O Walkhoff W A Price A Cieszynski W D Coolidge H R Raper F W McCormack... benefit of the patient Whereas Essentials of Dental Radiography for Dental Assistants and Hygienists is written primarily for dental assisting and dental hygiene students, practicing dental assistants,