Ebook Diagnostic imaging oral and maxillofacial: Part 1

(BQ) Part 1 book Diagnostic imaging oral and maxillofacial presents the following contents: Oral cavity, nose and sinuses, temporal bone, base of skull, cervical spine, suprahyoid neck, teeth, oral cavity, mandible and maxilla.

Diagnostic Imaging Oral and

Maxillofacial

Table of Contents

Diagnostic Imaging - Oral and Maxillofacial 9

Cover 9

Authors 9

Dedication 11

Preface 12

Acknowledgements 12

Part I - Anatomy 13

Section 1 - Oral Cavity 13

1 Teeth 13

2 Dental Restorations 24

3 Dental Implants 31

4 Maxilla 44

5 Mandible 51

6 Tongue 59

7 Retromolar Trigone 63

8 Sublingual Space 68

9 Submandibular Space 73

10 Oral Mucosal Space - Surface 78

Section 2 - Nose and Sinuses 81

11 Sinonasal Overview 81

12 Ostiomeatal Complex 96

13 Pterygopalatine Fossa 101

Section 3 - Temporal Bone 107

14 Temporomandibular Joint 107

15 External, Middle, and Inner Ear 113

Section 4 - Base of Skull 120

16 Anterior Skull Base 120

17 Central Skull Base 127

18 Styloid Process and Stylohyoid Ligament 134

Section 5 - Cranial Nerves 140

19 Cranial Nerve 5 140

20 Cranial Nerve 7 153

Section 6 - Cervical Spine 162

21 Craniocervical Junction 162

Section 7 - Suprahyoid Neck 173

22 Suprahyoid Neck Overview 173

23 Parapharyngeal Space 180

24 Nasopharynx and Oropharynx 185

25 Masticator Space 192

26 Parotid Space 197

27 Carotid Space 202

28 Retropharyngeal Space 207

29 Perivertebral Space 212

30 Lymph Nodes 217

31 External and Internal Carotid Arteries 222

Part II - Diagnoses 230

Section 1 - Teeth 230

I Developmental Alterations in Size and Shape of Teeth 230

32 Hypodontia 230

33 Hyperdontia 233

34 Macrodontia, Gemination, and Fusion 236

35 Microdontia 239

36 Concrescence 240

37 Talon Cusp 242

38 Dens Invaginatus 243

39 Enamel Pearls 245

40 Taurodontism 246

41 Dilaceration 248

42 Supernumerary Roots 249

II Developmental Alterations in Structure of Teeth 251

43 Amelogenesis Imperfecta 251

44 Dentinogenesis Imperfecta 257

45 Dentin Dysplasia 261

46 Regional Odontodysplasia 262

III Acquired Alterations of Teeth and Supporting Structures 264

47 Attrition 264

48 Abrasion 267

49 Erosion 269

50 Abfraction 270

51 Turner Dysplasia 272

52 Internal and External Resorption 274

53 Hypercementosis 280

IV Trauma 282

54 Concussion 282

55 Luxation 284

56 Root Fractures 289

V Infection - Inflammation 293

57 Dental Caries 293

58 Periapical Rarefying Osteitis 298

59 Periapical Sclerosing Osteitis 305

60 Periodontal Disease 308

VI Miscellaneous 317

61 Gubernaculum Dentis 317

Section 2 - Oral Cavity 320

I Congenital - Genetic 320

62 Submandibular Space Accessory Salivary Tissue 320

63 Lingual Thyroid 323

64 Dermoid and Epidermoid Cysts 326

65 Lymphatic Malformation 333

66 Submandibular Gland Aplasia-Hypoplasia 339

67 Foregut Duplication Cyst in Tongue 343

II Infection 346

68 Oral Cavity Soft Tissue Infections 346

III Inflammation 352

69 Ranula 352

70 Submandibular Gland Sialadenitis 358

78 Submandibular Gland Carcinoma 385

79 Submandibular Space Nodal Non-Hodgkin Lymphoma 388

80 Oral Tongue SCCa 391

81 Floor of Mouth SCCa 398

82 Gingival SCCa 401

83 Retromolar Trigone SCCa 404

84 Submandibular Space Nodal SCCa 408

85 Buccal Mucosa SCCa 411

86 Hard Palate SCCa 414

VI Miscellaneous - Idiopathic 417

87 Motor Denervation CN12 417

88 Submandibular Sialoliths 421

Section 3 - Mandible and Maxilla 424

I Normal Variants 424

89 Buccal and Palatal Exostoses 424

90 Torus Mandibularis 427

91 Torus Palatinus 430

92 Accessory Mandibular Canal 433

93 Mandibular Salivary Gland Defect 436

94 Mandible-Maxilla Idiopathic Osteosclerosis 442

II Congenital - Genetic 445

95 Clefts 445

96 Cleidocranial Dysplasia 448

97 Pierre Robin Sequence 452

98 Treacher Collins Syndrome 455

III Trauma 458

99 Mandible Fracture 458

100 Nasoethmoid Complex Fracture 464

101 Complex Midfacial Fracture 468

102 Zygomaticomaxillary Complex Fracture 471

103 Trans-facial Fracture 474

IV Infection - Inflammation 479

104 Mandible-Maxilla Osteomyelitis 479

105 Mandible-Maxilla Osteoradionecrosis 485

106 Mandible-Maxilla Osteonecrosis 491

V Cysts, Odontogenic 498

107 Dentigerous Cyst 498

108 Lateral Periodontal Cyst 504

109 Residual Cyst 508

110 Buccal Bifurcation Cyst 511

VI Cysts, Nonodontogenic 517

111 Mandible-Maxilla Aneurysmal Bone Cyst 517

112 Nasopalatine Duct Cyst 523

113 Nasolabial Cyst 530

114 Mandible-Maxilla Simple Bone Cyst 533

VII Fibro-osseous Lesions 539

115 Periapical Cemental Dysplasia 539

116 Florid Cemento-osseous Dysplasia 546

117 Cemento-ossifying Fibroma 552

118 Mandible-Maxilla Fibrous Dysplasia 558

119 Paget Disease 564

120 Cherubism 570

VIII Neoplasm, Benign, Odontogenic 577

121 Odontoma 577

122 Adenomatoid Odontogenic Tumor 583

123 Ameloblastoma 586

124 Ameloblastic Fibroma 592

125 Ameloblastic Fibro-odontoma 598

126 Calcifying Epithelial Odontogenic Tumor 601

127 Calcifying Cystic Odontogenic Tumor 604

128 Cementoblastoma 607

129 Odontogenic Myxoma 611

130 Central Odontogenic Fibroma 614

131 Keratocystic Odontogenic Tumor 617

132 Basal Cell Nevus Syndrome 624

IX Neoplasm, Benign, Nonodontogenic 627

133 Central Hemangioma 627

134 Osteoid Osteoma 630

135 Osteoblastoma 634

136 Mandible-Maxilla Osteoma 637

137 Nerve Sheath Tumor 640

138 Neurofibromatosis Type 1 646

139 Desmoplastic Fibroma 653

X Neoplasm, Malignant, Odontogenic 656

140 Malignant Ameloblastoma and Ameloblastic Carcinoma 656

XI Neoplasm, Malignant, Nonodontogenic 659

141 Mandible-Maxilla Metastasis 659

142 Mandible-Maxilla Osteosarcoma 668

143 Mandible-Maxilla Chondrosarcoma 674

144 Primary Intraosseous Carcinoma 680

145 Central Mucoepidermoid Carcinoma 683

146 Burkitt Lymphoma 686

147 Non-Hodgkin Lymphoma 692

148 Multiple Myeloma 698

149 Ewing Sarcoma 705

150 Leukemia 711

XII Tumor-like Lesions 715

151 Mandible-Maxilla Central Giant Cell Granuloma 715

152 Langerhans Histiocytosis 721

Section 4 - Temporomandibular Joint 728

I Congenital Disorders 728

153 Condylar Aplasia 728

154 Hemifacial Microsomia 731

II Developmental Acquired Disorders 737

155 Condylar Hyperplasia 737

156 Coronoid Hyperplasia 747

157 Condylar Hypoplasia 750

158 Fibrous Ankylosis 756

159 Bony Ankylosis 759

V Degenerative Disorders 789

167 TMJ Degenerative Disease 789

168 TMJ Synovial Cyst 795

169 Condylysis 798

VI Disc Derangement Disorders 807

170 Disc Displacement with Reduction 807

171 Disc Displacement without Reduction 811

172 Adhesions 814

VII Neoplasm, Benign 817

173 TMJ Osteoma 817

174 TMJ Osteochondroma 820

VIII Tumor-like Lesions 826

175 TMJ Calcium Pyrophosphate Dihydrate Deposition Disease 826

176 TMJ Synovial Chondromatosis 833

IX Neoplasm, Malignant 839

177 TMJ Osteosarcoma 839

178 TMJ Chondrosarcoma 842

179 TMJ Metastasis 848

X Miscellaneous 851

180 TMJ Simple Bone Cyst 851

181 TMJ Aneurysmal Bone Cyst 854

Section 5 - Maxillary Sinus and Nasal Cavity 857

I Normal Variants 857

182 Deviated Nasal Septum 857

183 Concha Bullosa 859

184 Accessory Ostia 860

II Developmental 863

185 Hypoplasia-Aplasia 863

III Inflammation 869

186 Mucus Retention Pseudocyst 869

187 Sinonasal Mucocele 873

188 Sinonasal Wegener Granulomatosis 879

189 Sinonasal Polyposis 885

190 Acute Rhinosinusitis 892

191 Chronic Rhinosinusitis 898

192 Odontogenic Sinusitis 904

193 Allergic Fungal Sinusitis 907

194 Invasive Fungal Sinusitis 910

195 Mycetoma 916

196 Invasive Pseudotumor 920

IV Neoplasm, Benign 923

197 Sinonasal Inverted Papilloma 923

198 Sinonasal Ossifying Fibroma 929

199 Sinonasal Osteoma 935

V Neoplasm, Malignant 941

200 Sinonasal Squamous Cell Carcinoma 941

201 Sinonasal Adenoid Cystic Carcinoma 945

202 Nasopharyngeal Carcinoma 948

203 Sinonasal Malignant Melanoma 954

VI Tumor-like Lesions 958

204 Sinonasal Fibrous Dysplasia 958

Section 6 - Masticator Space 964

I Normal Variants 964

205 Pterygoid Venous Plexus Asymmetry 964

II Infection 967

206 Masticator Space Abscess 967

III Degenerative 973

207 Masticator Muscle Atrophy 973

IV Neoplasm, Benign 980

208 Masticator Space CNV3 Schwannoma 980

209 Fibromatosis 983

V Neoplasm, Malignant 989

210 Masticator Space Chondrosarcoma 989

211 Masticator Space Sarcoma 993

212 Masticator Space CNV3 Perineural Tumor 999

VI Miscellaneous - Idiopathic 1005

213 Benign Masticator Muscle Hypertrophy 1005

Section 7 - Parotid Space 1009

I Inflammatory 1009

214 Parotid Sialadenitis 1009

215 Parotid Sialoliths 1012

216 Benign Lymphoepithelial Lesions-HIV 1015

II Neoplasm, Benign 1021

217 Parotid Benign Mixed Tumor 1021

218 Warthin Tumor 1027

219 Parotid Schwannoma 1033

III Neoplasm, Malignant 1037

220 Parotid Malignant Mixed Tumor 1037

221 Parotid Mucoepidermoid Carcinoma 1040

222 Parotid Adenoid Cystic Carcinoma 1046

223 Parotid Non-Hodgkin Lymphoma 1049

224 Metastatic Disease of Parotid Nodes 1055

IV Autoimmune 1061

225 SjoGren Syndrome 1061

Part III - Differential Diagnoses 1064

Section 1 - Teeth 1064

I Alterations in Tooth Number 1064

226 Extra Teeth 1064

227 Missing Teeth 1069

II Alterations in Tooth Morphology - Shape 1073

228 Crown Changes 1073

229 Root Changes 1077

Section 2 - Mandible and Maxilla 1085

I Alterations in Supporting Structures of Teeth 1085

230 Periapical Radiolucencies 1085

231 Periapical Radiopacities and Mixed Lesions 1093

232 Floating Teeth 1097

233 Widened Periodontal Ligament Space 1101

234 Lamina Dura Changes 1106

242 Ground-Glass and Granular Radiopacities 1164

243 Generalized Radiopacities 1171

IV Periosteal Reactions 1176

244 Periosteal Reactions 1176

Section 3 - Oral Cavity 1186

I Anatomically Based Lesions 1186

245 Submandibular Space Lesions 1186

246 Parotid Space Lesions 1194

247 Sublingual Space Lesions 1202

248 Oral Mucosal Space-Surface Lesions 1209

249 Root of Tongue Lesions 1217

II Miscellaneous 1224

250 Soft Tissue Calcifications 1224

Section 4 - Temporomandibular Joint 1232

I Changes in Condylar Size and Function 1232

251 Small Condyle 1232

252 Large Condyle 1240

253 Limited Condylar Translation 1248

II Mass Lesions 1255

254 TMJ Radiolucencies 1255

255 TMJ Radiopacities 1259

III Miscellaneous 1264

256 TMJ Articular Loose Bodies 1264

Section 5 - Maxillary Sinus and Nasal Cavity 1268

I Nasal Lesions 1268

257 Perforated Nasal Septum 1268

258 Nasal Lesion without Bony Destruction 1272

259 Nasal Lesion with Bony Destruction 1280

260 Sinonasal Fibro-osseous and Cartilaginous Lesions 1287

II Sinus Lesions 1291

261 Paranasal Sinus Lesions without Bony Destruction 1291

262 Paranasal Sinus Lesions with Bony Destruction 1299

III Miscellaneous 1307

263 Displaced Dental Structures into Antrum 1307

Index 1312

A 1312

B 1313

C 1314

D 1317

E 1318

F 1319

G 1320

H 1320

I 1321

J 1321

K 1322

L 1322

M 1323

N 1327

O 1328

P 1332

Q 1335

R 1335

S 1336

T 1341

U 1343

V 1343

W 1343

Z 1343

Diagnostic Imaging - Oral and Maxillofacial

Program Director, Oral Medicine and Oral Radiology

Marquette University School of Dentistry

H Ric Harnsberger MD

Professor

Department of Radiology and Otolaryngology

R.C Willey Chair in Neuroradiology

University of Utah School of Medicine

Salt Lake City, UT

Axel Ruprecht DDS, MScD, FRCD(C)

Gilbert E Lilly Professor of Diagnostic Sciences

Professor and Director of Oral and Maxillofacial Radiology

Department of Oral Pathology, Radiology, and Medicine

Professor of Radiology; Anatomy and Cell Biology

University of Iowa

Iowa City, IA

Byron W Benson DDS, MS

Professor and Vice Chair

Department of Diagnostic Sciences

Texas A&M Health Science Center

Baylor College of Dentistry

Dallas, TX

Margot L Van Dis DDS, MS

Professor

Department of Oral Pathology, Medicine, and Radiology

Indiana University School of Dentistry

Professor of Radiology and Otolaryngology

Chief, Head and Neck Neuroradiology

Medical College of Milwaukee

Milwaukee, WI

Surgery, and Biomedical Informatics

University of Utah School of Medicine

Salt Lake City, UT

Hilda E Stambuk, MD

Associate Attending of Radiology

Clinical Head of Head and Neck Imaging

Memorial Sloan - Kettering Cancer Center

Associate Professor of Radiology

Weill Medical College of Cornell University

New York, NY

Deborah R Shatzkes, MD

Associate Professor of Radiology

Columbia University College of Physicians and Surgeons

Director of Head and Neck Imaging

St Lukes - Roosevelt Hospital Center

New York, NY

Barton F Branstetter, IV, MD

Professor of Radiology, Otolaryngology,

and Biomedical Informatics

University of Pittsburgh School of Medicine

Director of Head and Neck Imaging

University of Pittsburgh Medical Center

Pittsburgh, PA

Rebecca S Cornelius, MD

Professor of Radiology and Otolaryngology - Head

and Neck Sugery

University of Cincinnati College of Medicine

University Hospital - UC Health

Cincinnati, OH

Bernadette L Koch, MD

Professor of Radiology and Pediatrics

University of Cincinnati College of Medicine

Associate Director of Physician Services and Education

Cincinnati Children's Hospital Medical Center

Cincinnati, OH

Kristine M Mosier, DMD, PhD

Associate Professor of Radiology

Chief, Head and Neck Radiology

Indiana University

Department of Radiology and Imaging Sciences

Indianapolis, IN

Caroline D Robson, MBChB

Associate Professor of Radiology

Harvard Medical School

Operations Vice Chair, Radiology

Director of Head and Neck Imaging

Children's Hospital, Boston

Boston, MA

Dedication

“No man is an island” as the quotation goes So it is with this compilation, which is the result of the

combined efforts of the intrepid group of authors, Axel, Dania, David, Grace, Margot, Pete, Ric, and

Susanne, who embarked on this journey with me almost two years ago Many thanks are owed to them for

their dedication and hard work A special thanks is due to Dania Tamimi whose insight and vision was the original inspiration for this book and who has been a source of wisdom and support throughout the writing.

We are grateful to the many colleagues who shared images with us, but I wish to recognize two in

particular, Mansur Ahmad and Marcel Noujeim, who gave generously from their libraries and whose images feature frequently in this tome

Many thanks to Kellie Heap at Amirsys who possesses saint-like patience and who was unbelievably helpful and the glue that held our team together And to Ric Harnsberger, what can I say? Thank you, thank you, for having faith in me and giving me this incredible opportunity It has been an honor and a pleasure to work with the remarkably talented people at Amirsys

Lastly, thanks to my family, Karl, Sophie, Ben, Natalie, Alex, and Jack for their patience and understanding And to Jack in particular: Your mom is back … put the X-box away :-)

L J K

Preface

It is with great pleasure that we present to you this first edition of the Diagnostic Imaging series dedicated

to oral and maxillofacial radiology The book was written by oral and maxillofacial radiologists and offers a dentist's perspective on oral and maxillofacial imaging with complete and accurate dental anatomy and nomenclature, as well as findings that affect the many aspects of dental treatment This book differs from the traditional Diagnostic Imaging format in that it contains anatomy, diagnoses, and differential diagnoses sections within the same volume

Anatomy section: The 31 chapters in this section cover the spectrum of oral and maxillofacial anatomy from embryology of the teeth to carotid arteries Each chapter is extensively illustrated with the

extraordinary graphics that have become synonymous with the Amirsys name The inclusion of this section underscores our belief that a comprehensive knowledge of the anatomy of the region is an essential component of the radiographic interpretation process

Diagnoses section: This section contains 185 chapters organized within anatomically oriented subdivisions beginning with conditions affecting the teeth and ending with parotid space lesions Included in this section

is an extensive collection of temporomandibular joint disorders While scarcity of images did not allow us

to include some of the more esoteric diagnoses, we think you will find all of the common and most of the not-so common lesions encountered in the oral and maxillofacial region

Differential diagnoses section: There are 38 chapters included in this section, which offers a unique and intuitive method for interpreting pathology according to radiographic appearance

This is an image-rich textbook, containing over 2,300 images in print, and offers the reader a

comprehensive review of the oral and maxillofacial complex Whenever possible and appropriate, beam CT (CBCT) and CT images have been included to illustrate the three-dimensional aspects of the anatomy and pathology The electronic version of the book contains many, many more images, as well as information that was excluded from the print book because of space constraints The electronic version also allows for linking between chapters, allowing the reader to easily navigate between the different sections of the book

cone-We trust that this textbook will serve as a useful tool to both the neophyte and the seasoned radiologist, as well as those dental specialists or general practitioners who are currently using CT and/or CBCT technology

or anticipate using this technology in the future Medical radiologists with an interest in the oral and

maxillofacial region will find this book a valuable companion to Diagnostic Imaging: Head and Neck, Second Edition

Wes Price, MS, CMI

Art Direction and Design

 Humans have 2 dentitions: Primary and permanent

 Teeth are divided into maxillary (upper) and mandibular (lower)

 Each jaw is divided into 2 quadrants: Right and left separated by midline

 Each quadrant has 5 primary and 8 permanent teeth

o Primary: 2 incisors (central and lateral), 1 canine, 2 molars (1st and 2nd)

o Permanent: 2 incisors (central and lateral), 1 C, 2 PM (1st and 2nd), 3 M (1st, 2nd, and 3rd)

 Teeth can be named or numbered

 Naming teeth should follow this sequence: Dentition → jaw → side → tooth name

o Example: Primary maxillary right 1st molar; permanent mandibular left canine

o Exceptions are premolars and 3rd molars: Only present in permanent dentition, so no need

to use “permanent”

o If only permanent teeth are present (all primary teeth have been exfoliated), no need to use “permanent”

 Numbering teeth depends on country

o Most countries use FDI system for numbering

 Quadrants are numbered

 Permanent: Upper right (UR) = 1, upper left (UL) = 2, lower left (LL) = 3, lower right (LR) = 4

 Primary: Upper right (UR) = 5, upper left (UL) = 6, lower left (LL) = 7, lower right (LR)

= 8

 Teeth are numbered

 Permanent: Central Inc = 1, lateral Inc = 2, C = 3, 1st PM = 4, 2nd PM = 5, 1st M = 6, 2nd M = 7, 3rd M=8

 Primary: Central Inc = 1, lateral Inc = 2, C = 3, 1st M = 4, 2nd M = 5

 Example: Permanent mandibular right 1st M = tooth #46 (pronounced “four-six”)

o United States uses universal system

 Only teeth are numbered

 Permanent teeth start with #1 (maxillary right 3rd M) and go to #16 (maxillary left 3rd M) pronounced “sixteen”

 Mandibular left 3rd M is #17 (seventeen) and goes to mandibular right 3rd M #32 (thirty-two)

 Primary teeth are labeled with letters A → T starting with last molar on upper right:

UR → UL→ LL → LR

o Other tooth numbering systems exist; check with local dental organization

o When in doubt, describe teeth by name

Anatomy Relationships

 When describing teeth or objects in relation to teeth, conventional anatomic positions (inferior, posterior, medial, lateral, anterior, posterior) are not used

 Position is described in relation to

o Midline of arch (i.e., line between central incisors), not anatomical midline

 All surfaces of teeth that are in direction of midline of arch are “mesial”

 All surfaces of teeth away from midline of arch are “distal”

o Inside or outside of arch

 Surfaces toward face are facial (can use buccal if posterior, labial if anterior)

 Surfaces toward tongue are lingual (can use palatal if maxillary)

o Anatomic tooth

 If above crown of tooth, use “coronal to”

 If below apices of tooth, use “apical to”

Eruption Patterns

 3 phases of eruption: Primary, mixed, and permanent dentitions

 Primary dentition

o Starts to erupt between 6-12 months

o 1st teeth are usually lower central incisors; last teeth are 2nd molars

 Mixed dentition

o A combination of primary and permanent teeth have erupted

o 1st permanent teeth are permanent 1st molars at 6 years

o Exfoliation of primary incisors followed by eruption of permanent incisors (6-9 years)

o Exfoliation of primary mandibular Cs followed by eruption of permanent mandibular Cs

(9-10 years)

o Exfoliation of primary Ms followed by eruption of PMs (10-12 years)

o Exfoliation of primary maxillary Cs followed by eruption of permanent Cs (11-12 years)

 Teeth are made up of 4 basic anatomic structures: Enamel, dentin, cementum, and pulp

o Enamel

 Hardest substance in body = most mineralized (95% calcified) = highest radiographic density

 Covers crown of tooth; contacts dentin at dentinoenamel junction (DEJ)

 Contacts cementum at cementoenamel junction (CEJ)

 Develops from ameloblasts

 Not visible radiographically unless hypercementosis occurs

o Pulp (a.k.a “nerve”)

 Vital portion of tooth (tooth “dies” when pulp dies)

 Contains nerves and vessels that enter and emerge through apical foramen of tooth

 Most radiolucent portion of tooth

 Crown portion called “pulp chamber” with pointy “pulp horns”; root portion called

“pulp canal”

 Teeth are made up of crown and root

o Crown: Everything above CEJ

 Further subdivided into occlusal/incisal, middle, and cervical thirds

 Incisors have incisal edges as functional component; all other teeth have cusps

o Root: Everything below CEJ

 Further subdivided into cervical, middle, and apical thirds

 Teeth can have single root or be multirooted; area between roots of tooth is called

“furcation area”

 Roots are named according to location in alveolar process: Buccal, lingual, mesial, distal, mesiobuccal, distobuccal

Periodontium

 Primary function is to support teeth; when teeth are lost, periodontal bone recedes

 Made up of periodontal bone, periodontal ligaments, and gingiva

o Periodontal bone

 Portion of alveolar processes of maxilla and mandible that come in direct contact with teeth

 Most cervical aspect called “crest”; corticated when healthy

 If tooth is lost, most cervical aspect of bone is called “residual ridge”

 Bone at apex of tooth called “periapical bone”

 Bone in furcation area called “furcal bone”

 Thin radiopaque line seen radiographically lining tooth socket is called “lamina dura”

o Periodontal ligament (PDL)

 Multidirectional fibers that attach tooth to socket; offer resilience to tooth during function

 Radiographically seen as uniform radiolucent line on inside of lamina dura

 If loses uniformity, suspect pathology

 Houses epithelial rests of Malassez, which may contribute to formation of cyst lining for odontogenic cysts

 Position in relation to tooth can determine if lesion is attached to tooth structure (inside PDL) or not (outside PDL)

o Gingiva (a.k.a “gums”)

 Soft tissue component covering periodontal bone

 Attaches to root to form small gingival sulcus with crown; cannot be visualized radiographically

Tooth Development and Tumorigenesis

 Potential sources for development of tumors

o Pre-functional dental lamina (odontogenic epithelium with ability to produce tooth); more abundant distal to lower 3rd molars

o Post-functional dental lamina: Epithelial remnants such as rests of Serres in fibrous gingival tissue; epithelial cell rests of Malassez in PDL and reduced enamel organ epithelium (covers the enamel surface until tooth eruption)

o Basal cell layer of gingival epithelium (source of dental lamina)

o Dental papilla (origin of dental pulp); can be induced to produce odontoblasts and

synthesize dentin &/or dentinoid material

o Horizontal bitewings for caries and early periodontal disease detection

o Vertical bitewings for moderate to severe periodontal disease

o Periapical radiographs if periapical pathology is suspected

o Pros: High-resolution images showing fine changes in demineralization; low radiation dose, especially if F-speed film or digital radiography is used

o Cons: Limited to dimensions of intraoral film, cannot see lesions or impacted teeth if they extend beyond

 For general overview of teeth in jaws: Panoramic radiography

o Shows eruption pattern and impactions of teeth; presence of intraosseous pathology

o Pros: Cost effective; lower radiation dose when compared to CBCT

o Cons: Distortion, magnification and blurring can impede evaluation

 For relationship of impacted teeth with vital anatomic structures: CBCT

o Can show inferior alveolar nerve (IAN) canals in relation to 3rd molars if extraction is planned

o Can show relationship of impacted canines to anterior superior alveolar canal, nasopalatine canal, and floor of nasal cavity

o Pros: 3D representation of 3-dimensional structures; 3D reformations can be obtained to give exact visualization of anatomy

o Cons: Expensive imaging modality, generally not covered by insurance; higher radiation dose

(Top) Graphic shows stages of tooth development: (A) Initiation: Ectoderm develops oral epithelium and dental lamina, (B) Bud stage: Dental lamina grows into bud penetrating the ectomesenchyme, (C) Cap stage: Enamel organ forms cap surrounding dental papilla and surrounded by dental sac, (D) Bell stage: Differentiation of enamel organ and dental papilla into different cells types, (E) Apposition stage: Secretion

of dental tissue matrix, and (F) Maturation: Full mineralization of dental tissues (Bottom) Graphic shows stages of root development: (A) apposition stage, (B) enamel deposition completion at the cervical loop and formation of Hertwig epithelial root sheath from inner and outer enamel epithelium cells, (C) root sheath disintegration and fragmentation of some of its cells into epithelial rests of Malassez, and (D) formation of cementum and periodontal ligaments with persistence of these epithelial remnants, which may be the source of the epithelial component of some odontogenic cysts and tumors

P.I(1):5

TOOTH ERUPTION

(Top) Graphic shows process of tooth eruption: (A) enamel organ reduces to thin layers covering enamel and secretes enzymes, (B) fusion of the reduced enamel epithelium with the oral epithelium, (C)

disintegration of the central fused tissues, leaving a canal for tooth movement, and (D) peripheral fused tissues peel back from the crown as the tooth erupts and form initial junctional epithelium that migrate cervically to cementoenamel junction (Bottom) The age of the patient can be determined by examining the eruption of the teeth This CBCT 3D reformation shows that the permanent incisors and 1st molars have erupted, but the premolars have not This puts the patient's age at between 8-10 years 3D reformations can be helpful in evaluation of erupting teeth if malocclusion and malalignment are present Note that the maxillary right central incisor has not fully erupted although the apical foramen is almost closed This may

be due to ankylosis (loss of PDL) of the tooth (Courtesy 3D Diagnostix, Inc.)

(Top) The maxilla has 16 permanent teeth arranged in 2 quadrants: the upper right (UR) quadrant, also known as quadrant 1, and the upper left (UL) quadrant, also known as quadrant 2 Eruption ages are in parenthesis The functional cusps on the maxillary posterior teeth are lingual (palatal) cusps (Bottom) The mandible has 16 permanent teeth arranged in 2 quadrants: the lower left (LL) quadrant, also known as quadrant 3, and the lower right (LR) quadrant, also known as quadrant 4 Eruption ages are noted in parentheses The functional cusps on the mandibular posterior teeth are the buccal (facial) cusps The permanent maxillary and mandibular incisors and canines have similarly named deciduous predecessors The predecessors of the 1st and 2nd premolar teeth are the 1st and 2nd deciduous molars respectively The deciduous incisors and canines have a single root, the mandibular deciduous molars have 2 roots, and the maxillary deciduous molars have 3 roots

P.I(1):7

HUMAN DENTITIONS

(Top) Panoramic reformat of CBCT data shows a patient at the primary dentition stage All 20 primary teeth have erupted into the oral cavity and are in occlusion, but all permanent teeth are still unerupted

Examination of the follicles of the permanent teeth for any displacement or expansion is recommended when evaluating images for the primary dentition phase It is also important to note any missing

permanent teeth to aid in future orthodontic treatment planning (Middle) Panoramic radiograph shows a patient at the mixed dentition stage The upper and lower permanent 1st molars have erupted, as well as the upper and lower incisors As the premolars have not erupted yet, it means the patient's age is between

(Top) Graphic representation shows a mandibular 1st molar in cross section through the mesial root Identification of the location of pathology in relation to the DEJ and CEJ helps in classifying caries and periodontal disease Mandibular posterior teeth are tilted slightly lingually to fit the opposing teeth

following the curve of Wilson Cross sections of the teeth are the most common reformation for dental applications, such as implant and impaction analysis, as they allow for evaluation of alveolar bone width and height and accurate localization of the IAN canal (Bottom) Graphic representation shows sagittal cross section of a mandibular 1st molar The tooth is attached to the socket through the periodontal ligaments The crest of the healthy alveolar bone is located about 1-2 mm apical to the CEJ of a tooth Innervation and vasculature exit through the apical foramen, but on occasion lateral canals may exit through the lateral aspects of the root If pulpal death occurs, bacteria can seep through the lateral canals, causing lateral radicular abscesses and cysts, and through the apical foramina, causing periapical inflammation

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DENTAL RADIOGRAPHIC ANATOMY

(Top) Periapical radiograph shows normal dental and periodontal anatomy The periodontal ligament (PDL) space is a thin radiolucent line that surrounds the root of the tooth The lamina dura is a thin radiopaque line that surrounds the tooth socket radiographically Healthy alveolar bone crests (crestal laminae dura) are corticated Nutrient canals may appear as small corticated canals within the bone connected to the apical foramen (Courtesy M Kroona, DXT.) (Bottom) Periapical radiograph of the central incisors shows the normal anatomic landmarks in this area It is important to realize that soft and hard tissue superimpositions may occur when imaging teeth, and their recognition is necessary to determine normal from abnormal Evaluation of the interproximal contact point and crown contours is important as caries tends to occur

(Top) Cross sections and panoramic and 3D reformations using Simplant® software show the IAN canal traveling between the roots of the distoangularly impacted mandibular left 3rd molar (Courtesy 3D Diagnostix, Inc.) (Middle) Panoramic and 3D reformations show a horizontally impacted left 3rd molar with its crown oriented distally and an impacted supernumerary tooth (4th molar) with its crown oriented mesially, both lying on top of the left IAN canal The right 3rd molar is horizontally impacted with its crown oriented mesially CBCT imaging can aid in predicting and preventing nerve damage when removing 3rd molars surgically (Courtesy 3D Diagnostix, Inc.) (Bottom) 3D reformation shows the left IAN going through the mesial root of the mesioangularly impacted mandibular left 3rd molar This occurs during tooth

development due to proximity of the tooth follicle to the IAN, which is engulfed in the root as it develops and calcifies (Courtesy 3D Diagnostix, Inc.)

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TOOTH IMPACTIONS

(Top) CBCT 3D reformation with transparent bone shows the vertical impaction of the permanent canines with lingual placement of the crowns and slight facial tipping of the roots Knowledge of this orientation aids the surgeon in deciding on the entry point for either extraction or exposure of the crowns for

placement of an orthodontic bracket (Courtesy 3D Diagnostix, Inc) (Middle) The bone can also be

“removed” on CBCT 3D reformations to further visualize the relationship of the teeth with one another This image shows unerupted maxillary canines with the crowns oriented facially The roots are not

completely formed (Courtesy 3D Diagnostix, Inc.) (Bottom) CBCT 3D reformation using Simplant® software shows an impacted mandibular canine The position of the impacted tooth in relation to the erupted dentition can easily be determined with 3D reformation Virtual extractions (digital removal of teeth) can also be performed (Courtesy 3D Diagnostix, Inc.)

2 Dental Restorations

TERMINOLOGY

Definitions

o Binds to enamel through acid-etching bonding

o Initially radiolucent, now mixed with radiopaque fillers

o More radiodense than enamel, but less than metal

 Glass ionomer

o Tooth-colored restoration

o Binds to dentin chemically

o Used on root lesions where there is no enamel present for acid etching

o Also used as a base under other large restorations

Prosthetic

 Crowns

o Full or partial tooth coverage

o Full cast metal, full porcelain, or porcelain fused to metal (PFM)

o Tooth must be “prepped”: Ground down to specific dimensions to create space for crown material

 Bridges

o Replace missing teeth by crowning at least 2 adjacent teeth (abutments)

o Portion that replaces missing tooth called “pontic”

o Bridge supported by 1 tooth is called “cantilever bridge”

o Bridge can be supported by implants

 Post and core

o Core: Cast metal replacement of tooth structure to mimic crown prep; crown placed on top

of it

o Post: Metal rod affixed to or cast with core to anchor it to root canal

 Implants

o Osseointegrated root form replacement of teeth restored with crown

o Discussed in implant chapter

 Complete and partial dentures

o Removable dentures used when several or all teeth are missing

o Should be removed from mouth prior to imaging to prevent metal artifact unless scan with denture is requested

Endodontics

 Gutta percha

o Cone-shaped flexible radiopaque material that can be condensed to fill tapering prepared root canal

o Should be no more than 1 mm from apex inside root; 0.5 mm is ideal

o If extends beyond apex, called “overfill”

o If more than 1 mm from apex (within root canal) called “underfilled” or “short”

 Sealer cement

o Viscous radiopaque material that seals gaps between cones

o May extend beyond apex of tooth and cause rarefaction of bone; most are biocompatible Orthodontics

o Stainless steel wires that follow outline of arch

o Fixed to brackets and bands with elastic &/or ligature wire

 Other fixed appliances

o Anchored to posterior teeth through bands

o May have several metallic spring and loop components as well as acrylic components Pediatrics

 Stainless steel crown

o Prefabricated crown

o Used when tooth structure cannot be restored by amalgam alone, or when tooth is root canal-treated (pulpotomy or pulpectomy)

o Lost when tooth is exfoliated

 Space maintainer

o Teeth will drift mesially when adjacent mesial tooth is extracted

o To ensure enough space for permanent successor tooth, space maintainer is placed on tooth adjacent to edentulous space

o Many different types: Fixed and removable; unilateral and bilateral

o Band and loop space maintainer: Made of band soldered to thick wire formed to abut with tooth mesial to edentulous space, preventing drift

ANATOMY IMAGING ISSUES

Imaging Recommendations

 MR for orthodontic patients

 If MR of head and neck

o Temporary removal of fixed and removable orthodontic appliances to prevent artifact

o If MR of other body structures

 Stainless steel archwire is magnetic and should be removed

 All orthodontic brackets and bands should be secured Imaging Pitfalls

 Dental restorations can cause metal streaking and beam hardening artifact on CT and signal voids

on MR, marring evaluation of adjacent bone and soft tissue

o Plain film radiographic and clinical examination is recommended for evaluation of bone and dental lesions if artifact is excessive

o To reduce artifact when examining oral cavity soft tissues on CT and MR, obtain scans without teeth crowns in field of view

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Image Gallery

PERIAPICALS AND AXIAL CBCT

(Top) Bitewing radiograph shows several posterior restorations Amalgam is metallic and, therefore, appears completely radiopaque (image void) Posterior composite restorations can be used for more esthetic results if clinically indicated, and appear radiolucent (if of 1st generation composites), posing a diagnostic challenge if evaluating for recurrent caries Composites with radiopaque fillers appear

moderately radiopaque (Courtesy B Friedland, BDS.) (Middle) Bitewing radiograph shows 2 types of amalgam restorations that are named according to surfaces replaced (occlusal [class I], mesio- or disto-occlusal [class II], amalgam build-up, etc.) If treatment of a tooth has not been completed, or if a period of pulpal healing is required after deep caries excavation, a temporary (interim) filling may be placed If a root canal-treated tooth is awaiting a crown, a cotton ball is placed to separate the gutta percha from the sticky temporary filling (Courtesy B Friedland, BDS.) (Bottom) Axial CBCT shows several anterior composite restorations which are currently radiopaque in varying degrees

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CBCT AXIAL AND PERIAPICALS

(Top) Axial CBCT shows multiple rounded well-defined radiolucencies on the proximal surfaces of the teeth, representing radiolucent oldgeneration composite restorations (Middle) A periapical radiograph shows a full metal coverage crown on the mandibular left 1st molar The contours of the crown should follow the original contours of the tooth with no overhangs or open margins This tooth is root canal treated, and the filling material in the mesial root is short, which may mean that a portion of the root canal was not

instrumented to remove debris, presenting a risk for periapical rarefying osteitis (Courtesy B Friedland, BDS.) (Bottom) A periapical radiograph shows a porcelain fused to metal (PFM) bridge The teeth onto which the bridge is fixed are called abutments and are covered with crowns The portion that replaces the missing tooth is called a pontic According to the number of teeth involved and replaced, the bridge is called a “3-unit, 4-unit, 5-unit, etc bridge “ (Courtesy B Friedland, BDS.)

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(Top) CBCT panoramic reformat shows multiple root canal-treated teeth that have been restored with post and core restorations followed by crowns A core recreates proper crown preparation outline when tooth structure is inadequate to support seating of the crown restoration A post anchors the core to the root and should not extend more than 2/3 of the root length Note large mucus retention pseudocyst in left

maxillary sinus (Middle) CBCT cross section shows root canal overfill of the central incisor with post and core that is not in line with the pulp canal Perforation of the tooth structure with the post can occur during preparation of the tooth Root canal filling in the periapical tissues may be attached to the apex or may be dissociated from it This foreign body may illicit an inflammatory reaction with symptoms of pain, or it may

be asymptomatic (Bottom) CBCT panoramic reformat shows full porcelain coverage crowns in the

maxillary and mandibular 1st molars These are cemented to the tooth with radiopaque cement

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CBCT REFORMATS

(Top) CBCT sagittal reformat shows a restoration of glass ionomer cement (GIC) in the buccal cervical region of this anterior tooth GICs are used to restore carious or tooth wear lesions that occur on the root surface of the tooth, or partially in enamel and partially in dentin (Middle) Coronal CBCT shows rapid palatal expander, which is a type of fixed appliance that is used to quickly increase the width of the

maxillary arch by splitting the intermaxillary suture before puberty It is cemented onto the posterior teeth

of the patient (Bottom) Axial CBCT shows orthodontic separators (spacers) that are placed between the molars before fixed appliances, such as a palatal expander or orthodontic bands, are applied Spacers are circular rubber bands about a centimeter in diameter placed between adjacent molars There may be 1-12

(Top) Axial CBCT shows a traditional fixed orthodontic appliance, which consists of: 1) brackets fixed to the facial surfaces of teeth, 2) bands that are cemented to 1 posterior tooth bilaterally, and 3) arch wire that is fixed to the brackets with elastic bands As the arch wire is highly magnetic, a visit to the orthodontist is recommended to remove the archwire if the patient is scheduled for an MR study (Middle) Axial CBCT shows caries in a tooth with an orthodontic band and bracket Meticulous oral hygiene should be

maintained for the duration of the orthodontic treatment to prevent plaque accumulation and the

development of caries (Bottom) Orthodontic brackets are placed on the crown of the tooth, and force is applied through the tightening of the orthodontic wire attached to them With the movement of the teeth, widening of the PDL space along the surface of the tooth away from the direction of the movement of the root is commonly seen In this cross sectional CBCT, the widening is noted on the lingual surface of the root due to the facial tipping of the root

3 Dental Implants

TERMINOLOGY

Definitions

 Metal devices that osseointegrate in alveolar process to replace missing teeth

o Usually made out of titanium and surgically placed into jawbone where tooth is missing

o Period of osseointegration is needed before crown placement, except in cases of

immediate implants IMPLANT TYPES AND PROCEDURES

Types of Implants

 Root form

o Most commonly used

o Cylindrical or may be tapered

o May be smooth or serrated (or have holes for osseointegration)

 Zygomatic

o Can be used with severe atrophy of maxillary alveolar process

 Pterygoid

o Can be used when there is severe atrophy of maxillary alveolar process or maxillectomies

 Mini orthodontic implants (temporary anchorage devices [TADs])

o Used for orthodontic anchorage for a variety of orthodontic procedures

o May be cylindrical, miniscrew or miniplates

 Subperiosteal

o Not used anymore

o Involves exposing bone surgically, making an impression, and creating implant to fit bone, which is then reexposed to allow for implant fitting and then covered with mucosa

 Blade type

o Not used anymore

o Thin in faciolingual dimension (hence name)

 Transosteal

o Components attach from inferior border of mandible through bone to alveolar process Augmentation of Deficient Alveolar Process

 Sinus grafting

o Graft material placed under sinus periosteum to give resorbed alveolar process height

 Can be introduced through Caldwell Luc procedure

 Ridge augmentation

o Resorbed facial bone can be augmented

o Screws may be used to retain graft

 Socket grafting

o Dense grainy material taking shape of tooth socket

o Can be confused with healing of socket by dense bone; correlate with clinical history

 Materials used in grafting

o Autologous bone

 Can be harvested locally from jaw bones or from iliac crest (for larger samples)

 Induces osteogenesis

o Allografts

 Freeze-dried bone or demineralized freeze-dried bone from cadavers

 Osteoinduction: Cells stimulated to form bone

 Does not show faciolingual dimension

Panoramic Radiography

 Can be used in all stages of treatment

 ↓ costly & ↓ radiation than more advanced imaging

 Inherent image distortion and magnification

 Does not show faciolingual dimension

Conventional Tomography

 Can be used for treatment planning, surgery, and healing phases

 Faciolingual dimension can be visualized

 Magnification occurs, but is uniform

 Less expensive and less radiation than CT

 Has less definition than plain film imaging

 Limited availability; being phased out by CBCT machines

CBCT Imaging

 Can be used for treatment planning, surgery, and evaluation of complications

 Ideal for evaluation of multiple sites and full mouth implant planning

 Measurements accurate within 1 mm

 Evaluation of bone density can be done

 Software can help with treatment planning through implant simulation and 3D reformation

 More costly and more radiation than 2-dimensional imaging techniques

 Metal streaking, beam hardening, and volume averaging artifacts impede evaluation of bone around existing implants

o Periapical radiography is recommended to evaluate healing and suspected failing implants MDCT Imaging

 Can be used for treatment planning, surgery, and evaluation of complications

 All other advantages of CBCT

 Ability to visualize soft tissue if needed

 Needs dental imaging software (e.g., “DentaScan”)

 Very costly and highest dose of radiation

 Metal streaking, beam hardening, and partial volume artifact impede evaluation of bone around

existing implants

MR Imaging

 Not indicated for implant imaging

 MR for other indication: Implants generally safe unless contain magnetically activated components

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Image Gallery

PROGRESSION OF BONE LOSS AFTER TOOTH EXTRACTION

(Top) Coronal graphic shows the progression of bone loss in the maxillary and mandibular posterior

alveolar processes when teeth are lost Due to the action of the buccinator muscles, the facial plate of the bone resorbs, resulting in an increasingly lingualized crest of the ridge Severe loss of mandibular alveolar bone may result in exposure of the IAN canal When replacing the missing teeth, the implants need to be placed in a fashion that allows appropriate intercuspation with the opposing tooth following the curve of Wilson, a mediolateral curve that contacts the buccal and lingual cusp tips of each side of the arch

(Bottom) Graphic shows progression of bone loss in the maxillary and mandibular anterior alveolar

processes The orbicularis oris muscle remodels the facial aspect of both processes, while the lingual aspect

of the mandibular process is resorbed due to action of the tongue The ridge becomes “knife-edge” and may require alveoloplasty or grafting to contour it to acceptable morphology Implant crowns should mimic

(Top) A curvilinear line is drawn on this axial image, following the curve of the arch where the implants will

be placed The line should run parallel to the facial and lingual cortices of the jaw bone of interest (Middle)

A panoramic reformation is generated from the curvilinear reformat, giving an overview of the area of interest A radiographic stent is recommended with all dental implant cases to show the orientation of the proposed implant in relation to the remaining alveolar bone in the area These may be worn by the patient during scanning or scanned separately on a model, fusing that image with the patient scan (Bottom) CBCT cross section shows slight lingual undercut in the area of the radiographic marker The orientation of the height measurement should align with the long axis of the marker post on radiographic stent The width measurement is taken perpendicular to the height measurement in the area of thinnest faciolingual width The purpose of any implant work-up is to avoid perforation of the lingual cortex and IAN (mandibular) canal

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IAN ANOMALIES

(Top) Cropped panoramic reformation of CBCT data shows that the inferior alveolar canals can exhibit many anomalies, such as double canals (as seen here) or anomalous branches with facial or lingual

foramina Thin slice panoramic reformats can show the presence of IAN canal anomalies These are

important to define during implant treatment planning to avoid surgical surprises (Middle) Cross section CBCT of the same patient shows a double IAN canal Anomalous canals may or may not be well corticated (Bottom) Coronal CBCT of the anterior mandible shows the extent of the incisive nerves The anterior intraosseous extension of the IAN is called the incisive nerve The incisive nerve comes off the IAN before it exits through the mental foramen, extending anteriorly to the midline where it may connect with the lingual canal, as seen here Because this is not always visible on radiographic imaging, during implant planning for the lower anterior region, special consideration should be given to the existence of this neurovascular bundle

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(Top) Panoramic reformat of CBCT data shows a maxillary sinus graft with implants in place This type of graft is placed with a Caldwell-Luc procedure called a sinus lift Graft material is placed between the mucosal lining of the sinus and the bony floor of the sinus to give height to alveolar bone that has either atrophied or been pneumatized by the maxillary sinus (Middle) Axial CBCT shows graft material particles placed on the facial surface of the maxillary anterior alveolar process to augment the ridge Autologous bone graft pieces may be fixed with fixation screws Depending on size, graft material takes from 4-10 months to resorb into the bone and create more height or width (Bottom) Cross section CBCT shows high-density grainy material noted in the socket of a maxillary central incisor This procedure is usually done at extraction to preserve the facial-lingual dimension of the bone, as the facial bone tends to resorb after extraction

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IMPLANT ERRORS

(Top) Sagittal CBCT shows implants replacing posterior teeth that have perforated the superior border of the inferior alveolar canal The apices of the implants are seen within the canal and are likely compressing

or lacerating the inferior alveolar nerve (Courtesy S White, DDS, PhD.) (Middle) Coronal CBCT from the same patient shows possible compression of the left inferior alveolar nerve Compare to the normal size and morphology of the IAN canal on the right side Patients with such injuries may present with pain, tingling, or paresthesia Such injuries can be avoided with appropriate imaging and treatment planning

(Top) Cross section CBCT shows an implant replacing a maxillary canine that was placed with excessive facial inclination Normally, the maxillary teeth overlap the mandibular teeth facially, and the lower

anterior teeth should be in functional occlusal contact with the lingual aspect of the maxillary teeth The angulation of the implant in this image would not allow restoration with a crown that is in contact with the mandibular canine Stripping of the the facial cortex of the maxillary alveolar bone is noted, which may compromise replacement Esthetics may also be compromised (Middle) Sagittal CBCT shows an implant apex fracture that can occur due to heavy loading of the implant, such as with clenching and bruxism, or during removal of an implant for other reasons (Bottom) CBCT panoramic reformat shows the implant replacing the maxillary right lateral incisor appearing to be in the right anterior superior alveolar canal This was confirmed on cross sections

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DIFFERENT TYPES OF IMPLANTS