Fundamentals of Oral and Maxillofacial Radiology

About the author J. Sean Hubar, DMD, MS, is Professor in the Department of Diagnostic Sciences at Louisiana State University School of Dentistry in New Orleans, Louisiana, USA.

• Acknowledgments ixAbout the Companion Website xPart One: Fundamentals 1A. Introduction 3What is dental radiology? 3What are x rays? 3What’s the big deal about x‐ray images? 5B. History 6Discovery of x rays 6Who took the world’s first “dental” radiograph? 8Dr. C. E. Kells, Jr., a New Orleans dentist and the early days of dental radiography 8C. Generation of X Rays 11D. Exposure Controls 13Voltage (V) 13Amperage (A) 13Exposure timer 14E. Radiation Dosimetry 15Exposure 15Absorbed dose 15Equivalent dose 15Effective dose 16F. Radiation Biology 17What happens to the dental x‐ray photons that are directed at a patient? 18Determinants of biologic damage from x‐radiation exposure 19G. Radiation Protection 221. Radiation protection: Patient 22Protective apron 23Collimation 24Filtration 25Digital versus analog 26Exposure settings 26Operator technique 262. Radiation protection: Office personnel 27How much occupational radiation exposure is permitted? 29H. Patient Selection Criteria 30I. Film versus Digital Imaging 32Film 32Digital imaging 33Imaging software 36J. What do Dental X‐ray Images Reveal? 38Alterations to the dentition 38Periodontal disease 39Growth and development 39Alterations to periapical tissues 40Osseous pathology 40Temporomandibular joint disorder 40Implant assessment (pre‐ and post‐placement) 40Identification of a foreign body 40K. Intraoral Imaging Techniques 411. Paralleling technique 42Maxillary incisors paralleling projection 45Maxillary cuspid paralleling projection 45Maxillary bicuspid paralleling projection 46Maxillary molar paralleling projection 46Mandibular incisor paralleling projection 47Mandibular cuspid paralleling projection 48Mandibular bicuspid paralleling projection 48Mandibular molar paralleling projection 492. Bisecting angle technique 50Maxillary incisor bisecting angle projection 51Maxillary cuspid bisecting angle projection 51Maxillary bicuspid bisecting angle projection 52Maxillary molar bisecting angle projection 52Mandibular incisor bisecting angle projection 53Mandibular cuspid bisecting angle projection 53Mandibular bicuspid bisecting angle projection 54Mandibular molar bisecting angle projection 543. Bitewing technique 55Bicuspid bitewing 56Molar bitewing 56Anterior bitewing projection 564. Distal oblique technique 575. Occlusal imaging technique 58Maxillary occlusal projection 59Mandibular occlusal projection 60L. Intraoral Technique Errors 61Cone‐cut 61Apex missing 62Elongation 63Foreshortening 63Overlapped contacts 64Missing contacts 64Overexposure and underexposure 65Motion artifact 66Foreign object 66M. Extraoral Imaging Techniques 681. Panoramic imaging 68Positioning the patient 69Exposure settings 71Advantages and disadvantages 71Technique errors 74Anatomic landmarks 842. Lateral cephalograph imaging 853. Cone beam computed tomography 86Introduction 86Anatomic landmarks 89N. Quality Assurance 96O. Infection Control 97Excerpt from “CDCGuidelines for Infection Control in Dental Health‐Care Settings” 97General instructions for cleaning and disinfecting a solid‐state receptor (courtesy of Sirona™) 98P. Occupational Radiation Exposure Monitoring 100Q. Hand‐held X‐ray Systems 102Dental radiographic examinations: recommendations for patient selection and limiting radiation exposure 102Commentary 102Part Two: Interpretation 105R. Localization of Objects (SLOB Rule) 107S. Recommendations for Interpreting Images 111T. X‐ray Puzzles: Spot the Differences 113U. Radiographic Anatomy 1241. Dental anatomy 1242. Anatomic landmarks of the maxillary region 126Radiopaque landmarks 126Radiolucent landmarks 1293. Anatomic landmarks of the mandibular region 133Radiopaque landmarks 133Radiolucent landmarks 136V. Dental Caries 141Limitations to visualizing caries on x‐ray images 141Classification of caries 143W. Dental Anomalies 149Number 149Size 149Shape 151Developmental factors 157Environmental factors 161X. Osseous Pathology (Alphabetic) 170Y. Lagniappe (Miscellaneous Oddities) 188Part Three: Appendices 195Appendix 1: FDA Recommendations for Prescribing Dental X‐ray Images 197Appendix 2: X‐radiation Concerns of Patients: Question and Answer Format 2001. How often should I get x rays taken? 2002. How much radiation am I receiving from dental x rays? 2003. Can I get cancer from dental x rays? 2014. Why do I need to wear a protective apron for dental x rays and why does the assistant leave the room before taking my x rays, if dental x rays are so safe? 2015. Your protective apron does not have a thyroid collar, why not? 2016. I am pregnant, should I get dental x rays taken? 2017. When should my child first get dental x rays taken? 2018. Will I glow in the dark after all of the x rays that I received at the dental office? 2029. What are 3‐D x rays? 20210. Why does the dentist require additional 3‐D x rays before placing my dental implant? 202Appendix 3: Helpful Tips for Difficult Patients 2031. Hypersensitive gag reflex 2032. Small mouth/shallow palate/ constricted arch/torus 2043. Large frenulum 2054. Trismus 2055. Cuspid superimposition 2056. Rubber dam 2067. Third molar imaging 206Appendix 4: Deficiencies of X‐ray Imaging Terminology 207Survey results 207Appendix 5: Tools for Differential Diagnosis 2101. Number 2102. Location 2103. Density 2114. Shape 2115. Size 2116. Borders 2127. Changes to surrounding anatomic structures 212Appendix 6: Table of Radiation Units 213Appendix 7: Table of Anatomic Landmarks 214Tooth 214Tooth‐related structures 214Landmarks associated with the maxilla 214Landmarks associated with the mandible 214Appendix 8: Table of Dental Anomalies 216Number 216Size 216Shape 216Developmental defects 216Environmental effects 216Appendix 9: Table of Osseous Pathology 217Radiolucent anomalies in the maxilla and mandible 217Radiopaque anomalies in the maxilla and mandible 217Mixed (radiolucent–radiopaque) anomalies in the maxilla and mandible 218Appendix 10: Common Abbreviations and Acronyms 219Appendix 11: Glossary of Terms 221Suggested Reading 238Index 251