Veterinary Oral Diagnostic Imaging

List of Contributors xv Preface xvii Acknowledgements xix 1 History, Physiology, Modality Options, and Safety for Diagnostic Imaging of the Oral Cavity 1 Brenda L. Mulherin History of Diagnostic Imaging 1 Discovery of X-rays 1 Developing of Safety Measures 1 Shortening of Exposure Time 1 Glass Plates to Film 2 Progression to Digital 2 Philosophy of Diagnostic Imaging 2 Choosing the Appropriate Modality 2 Ability to Interpret Findings 3 Radiographic Indications 3 Documentation of Disease 3 Value of Full-Mouth Radiography 3 American Animal Hospital Association Guidelines Regarding Dental Radiography 3 Intraoral Dental Radiographic Equipment 3 Generators 3 Wall-Mounted Units 4 Handheld Units 4 Mobile Units/Castor-Mounted Units 4 Film 4 Standard Film 5 Digital Image Acquisition 6 Radiographic Imaging 7 Basic Unit of an X-ray 7 Milliamperes (mA), Kilovoltage Peak (kVp), and Exposure Time 8 Radiographic Densities 9 Radiopaque 9 Radiolucent 10 Digital Image Creation 10 Creation of a Digital Image 10 Digital Imaging and Communications in Medicine Format (DICOM) 10 Pixels 10 Advanced Imaging Modalities 10 Computed Tomography 10 Cone Beam Computed Tomography (CBCT) 12 Magnetic Resonance Imaging 13 Definitions Relating to Imaging Modalities 13 Sagittal Plane 13 Transverse Plane 13 Dorsal Plane 14 Computed Tomography Window Width and Window Level 14 Window Width 15 Window Level 15 Other Common Viewing Windows 16 Bone Window 16 Soft Tissue Window 16 Radiation Safety 16 Radiation Safety Apparel 16 Collimation 16 As Low As Reasonably Achievable (ALARA) 17 Time, Distance, and Shielding 17 Time 17 Distance 17 Shielding 17 Radiation Safety Equipment Inspection 17 Protective Apparel 17 Care of Radiation Safety Equipment 18 Radiation Safety Inspection Protocol 19 References 20 2 Digital Dental Radiographic Positioning and Image Labeling 23 Brenda L. Mulherin and Chad Lothamer Benefits to Proper Positioning 23 Practicing Techniques 23 Use of Position Indicating Device (PID) 23 Positioning Techniques 24 Patient Positioning 24 Sternal Recumbency 25 Dorsal Recumbency 25 Lateral Recumbency 25 Sensor/Phosphor Plate/Film Placement 26 Basic Positioning of Sensor 27 Eliminating Unused Film Space 29 Visualization of the Crown and Space Apical to Root 29 Intraoral Parallel Technique 30 Ideal Radiographic Technique 30 Placement of Sensor for Parallel Technique 31 Size Matters 31 Alternative Positioning 32 Parallel Technique for Cats 32 Intraoral Bisecting Angle Technique 32 Plane of the Tooth, Plane of the Film, and the Angle that Bisects 32 Shadow Game: Elongation, Foreshortening, and the Bisecting Angle 32 Axis of the Sensor, the Tooth, and the PID 33 Positioning of the Patient Matters 35 Anatomical Variations 36 Uses of the Bisecting Angle Technique 36 Occlusal Radiographic Technique 37 Feline Maxillary Premolar and Molar Teeth 37 Extraoral Technique 37 “Almost Parallel” or “Near Parallel” Technique 39 Localization of the Palatal Roots 39 Techniques for Imaging Caudal Teeth in Small Patients 43 Technique Errors 44 Foreshortening and Elongation 44 Cone Cutting 46 Missing the Apex 47 Overexposed or Underexposed 49 Artifacts 50 Repeat Radiographs 51 Conclusion 52 References 53 3 Interpretation of Normal Radiographic Anatomy 55 Brenda L. Mulherin Value of Intraoral Radiographic Imaging 55 Quality of Images 56 Exposure Artifacts 56 Positioning Techniques 56 Parallel Technique 56 Bisecting Angle Technique 56 Positioning Artifacts 56 Elongation 56 Foreshortening 56 Cone Cutting 56 Missing the Apex 57 Mounting of Standard Dental Radiographs 57 Types of Mounting 57 Labial Mounting 57 Lingual Mounting 57 Labial Mounting of Standard Dental Radiographic Film 57 Lingual Mounting of Standard Radiographic Film 57 Digital Radiographic Mounting 58 Labial Mounting-Positioning of Teeth 59 Determining Maxilla from Mandible 59 Determining Right from Left 59 Modified Triadan Numbering System 62 Deciduous versus Permanent Teeth 65 Eruption Patterns 65 Mixed Dentition 66 Interpretation of Images 70 Tooth Root Numbers 75 Maxillary Teeth 75 Mandibular Teeth 77 Evaluation of the Structures 82 Crown 84 Root 90 Bone 105 Interpretation of Radiographic Shadows 105 Nomenclature 107 Where to Begin? 109 Conclusion 110 References 117 4 Interpretation of Common Oral Pathology in the Canine Patient 119 Brenda L. Mulherin and Chanda Miles Periodontal Disease 119 Stages of PD 120 Types of Bone Loss 123 Horizontal Bone Loss 123 Vertical Bone Loss 123 Furcation Bone Loss 124 Supernumerary Roots and Teeth 129 Canine Tooth Resorption 131 Types of Tooth Resorption 132 External Tooth Resorption 132 External Surface Resorption 132 Internal Tooth Resorption 134 Treatment of Tooth Resorption 134 Odontogenic Cysts 135 Dentigerous Cysts 135 Periapical Cysts 137 Treatment for Odontogenic Cysts 138 Tooth Fractures 138 Root Fractures 142 Retained Tooth Roots 142 Endodontic Disease 143 Etiology 143 Radiographic Signs of Endodontic Disease 148 Widened PDL Space 148 Loss of Lamina Dura 148 Periapical Lucency 148 External and Internal Root Resorption 149 Widened Pulp Canal 150 Pulp Canal Calcification 150 Apical Periodontitis 151 Acute Apical Abscess 151 Chronic Apical Abscess 152 Endodontic Therapy 154 Root Canal Therapy 154 Vital Pulp Therapy 156 Attrition and Abrasion 157 Eruption Abnormalities 159 Persistent Deciduous Teeth 159 Unerupted Teeth 162 Abnormal Eruption 163 Conclusion 165 References 165 5 Interpretation of Common Pathology in the Feline Patient 167 Brenda L. Mulherin and Chanda Miles Periodontal Disease 167 Types of Bone Loss 168 Buccal Alveolar Expansile Osteitis (BAEO) 168 Tooth Resorption 168 Stages and Types of Feline Tooth Resorption 177 Stages of Tooth Resorption 177 Types of Tooth Resorption 180 Criteria for Performing Crown Amputation/Intentional Root Retention 180 Supraeruption/Extrusion 185 Osteomyelitis and Osteitis 185 Retained Tooth Roots 187 Endodontic Disease 187 Conclusion 190 References 198 6 Oral Surgery: Neoplasia and Cystic Conditions 199 Megan Mickelson Radiographic Indications of Neoplasia (Benign and Malignant) 199 Benign Oral Tumors 200 Canine Acanthomatous Ameloblastoma (CAA) 200 Peripheral Odontogenic Fibroma (POF) 200 Feline Inductive Odontogenic Tumor (FIOT) 201 Malignant Oral Tumors 201 Nontonsillar Squamous Cell Carcinoma (SCC) 201 Papillary Squamous Cell Carcinoma (PSCC) 203 Oral Malignant Melanoma (MM) 204 Fibrosarcoma (FSA) 206 Osteosarcoma (OSA) 206 Multilobular Osteochondrosarcoma (MLO) 208 Radiographic Indications of Cystic Conditions 209 Dentigerous Cyst 209 Radicular Cyst 212 Canine Furcation Cyst 213 Surgical Ciliated Cyst 213 Lateral Periodontal Cyst 213 Odontogenic Keratocyst (OKC)/Canine Odontogenic Parakeratinized Cyst (COPC) 216 Compound and Complex Odontomas 216 Limitations of Dental Radiography for Neoplasia 216 Conclusion 230 References 230 7 Interpretation of Uncommon Pathology in the Canine and Feline Patient 235 Brenda Mulherin, Chanda Miles, and Michael Congiusta Introduction 235 Uncommon Conditions with Predilection for Canine Patients 235 Craniomandibular Osteopathy (CMO) 235 Idiopathic Calvarial Hyperostosis 237 Periostitis Ossificans (PO) 237 Malformed Roots/Root Hypoplasia 238 Dens Invaginatus/Dens in Dente 240 Uncommon Conditions Observed in both Canine and Feline Patients 245 Masticatory Myositis 245 Pulp Stones and Denticles 246 Osteosclerosis 247 Renal Secondary Hyperparathyroidism 248 Enamel Pearls 253 Uncommon Conditions with Predilection for Feline Patients 253 Dentition Abnormalities 253 Fused Roots 254 Supernumerary Roots 256 Supernumerary Teeth 257 Abnormal Eruption 257 Unerupted Teeth 258 Patellar Fracture and Dental Anomaly Syndrome (PADS) or Knees and Teeth Syndrome 258 Conclusion 262 Acknowledgment 262 References 262 8 Diagnostic Imaging of Exotic Pet Mammals and Zoo Animals 265 June Olds Dental Diagnostic Imaging for Nontraditional (Exotic) Animals 265 General Considerations for Exotic Companion Mammals 266 Restraint 266 Knowledge of Normal Anatomy 266 General Positioning and Projection Recommendations 267 Standard Radiography 267 Standard Radiographic Positions 267 Intraoral Radiographs 272 Intraoral Films Used Extraorally 275 Magnification Techniques 275 Anatomical Variations 275 Rabbits 275 Guinea Pigs and Chinchillas 276 Rats, Mice, Hamsters, Gerbils, and Other Commonly Kept Rodent Pets 283 Ferrets 287 African Pygmy Hedgehogs 287 Sugar Gliders 289 Prairie Dogs (Cyomys ludovicianus) 293 Captive Nondomestic or “Wild” Mammals 293 Nonhuman Primates 293 Carnivores 297 Radiographic Positioning and Techniques in Captive Animals 297 Animal Training 300 Other Dental Conditions in Zoologic Animals 304 Trauma 304 Attrition 304 Macropod Progressive Periodontal Disease (MPPD) 304 Molar Progression 308 Advanced Diagnostic Imaging in Exotic Pet Mammals and Zoo Animals 308 Standard Computed Tomography 308 Cone Beam Computed Tomography 312 Micro-computed Tomography 316 Considerations for Computed Tomography 321 Conclusion 326 Acknowledgment 327 References 327 9 Diagnostic Imaging and Interpretation of the Equine Patient 331 Joan Howard, Molly Rice, Kara Frerichs, and Beatrice Sponseller Introduction to Equine Dental Radiographs 331 Radiation Safety 332 Radiographic Systems 332 Direct Digital Radiographic System (DR) 332 Computed Tomography 332 Standard Radiographic System 332 Radiographic Technique 332 Guidelines for Radiographic Views 332 Concepts to Understand 332 Directing the Primary Beam Through the Interproximal Spaces 333 Open Mouth Oblique Cheek Teeth Projections 334 Radiographic Views 334 Lateral View 334 Dorsoventral View 336 Dorsal Ventral Oblique Projection of the Maxillary Cheek Teeth 338 Ventral Dorsal Oblique Projection of the Maxillary Cheek Teeth 340 Ventral Dorsal Oblique Projection of the Mandibular Cheek Teeth 340 Dorsal Ventral Oblique Projection of the Mandibular Cheek Teeth 340 Occlusal Intraoral View of the Maxillary Incisors and Canines 340 Occlusal Intraoral View of the Mandibular Incisors and Canines 343 Evaluation of an Image 346 Labial Mounting 346 Radiographic Anatomy 347 Radiographic Changes in Dental Disease 350 Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH) 352 Apical Infections 353 Periodontal Disease 354 Sinusitis 356 Neoplasia 357 Other Suggested Abnormalities to be Radiographed 358 Conclusion 360 Acknowledgment 372 References 372 10 Advanced Imaging of the Oral Cavity 373 Stephanie Goldschmidt Introduction to the Use of Advanced Imaging Techniques in the Maxillofacial Region 373 Magnetic Resonance Imaging (MRI) 373 Technical Principles of MRI 373 T1- and T2-Weighted Sequences 374 Other MRI Sequences 375 Indications for Use of MRI over CT in the Maxillofacial Region 376 Temporomandibular Joint Disease (TMD) 376 Salivary Gland Disease 376 Abnormalities in the Muscles of Mastication and Inability to Open/Close the Mouth 376 Conclusions on the Clinical Indication for Use of MRI 377 Computed Tomography (CT) 379 Technical Principles of Multidetector CT (MDCT) Scanners 380 Technical Principles of Cone Beam CT (CBCT) Scanners 382 Viewing CT Images 383 Differences in Image Characteristics Between CBCT and MDCT 387 Spatial Resolution 387 Soft Tissue Imaging 387 Artifacts 389 Other Impactful Differences in Practical Use Between MDCT and CBCT 389 Indications for Use of Either MDCT or CBCT in the Maxillofacial Region 389 Maxillofacial Trauma 389 Bony Pathology 390 Osteomyelitis/Osteonecrosis 390 Fibro-Osseous Disease 390 Osseous Neoplasia 391 Clefts 392 Indications for Multidetector CT only (not CBCT) in the Maxillofacial Region 395 Oral Neoplasia with a Soft Tissue Component 395 Soft Tissue Pathology 395 Indications for CBCT only (not MDCT) in the Maxillofacial Region 395 Dentoalveolar Trauma 396 Periodontal Disease 396 Endodontic Disease 396 Tooth Resorption 399 Diagnosis and Treatment of Missing Teeth 401 Conclusions on the Clinical Indication for Use of CBCT Versus MDCT 402 References 402 Index 407