Maxillofacial Cone Beam Computed Tomography: Principles, Techniques and Clinical Applications

Foreword
Contents
About the Editors
Contributors
Part I: Fundamentals of CBCT
	1: Historical Perspectives on CBCT
		1.1	 Introduction
		1.2	 Development of Maxillofacial CBCT Systems
			1.2.1	 Computed Tomography
			1.2.2	 Cone Beam Acquisition
			1.2.3	 CBCT Technology Transfer for Maxillofacial Applications
				1.2.3.1	 Early Maxillofacial CBCT Units
				1.2.3.2	 Current Status
		1.3	 Thoughts on the Future
		References
	2: What Is CBCT and How Does It Work?
		2.1	 Introduction
		2.2	 Stages of CBCT Imaging
			2.2.1	 Image Acquisition
				2.2.1.1	 X-ray Source
				2.2.1.2	 Projection Geometry
					Modified Geometric Configurations
						Volumetric Stitching
						Horizontal Off-Axis Geometry
						Vertical Off-Axis Geometry
				2.2.1.3	 Image Detector
			2.2.2	 Image Reconstruction
				2.2.2.1	 Pre-processing
				2.2.2.2	 Reconstruction
			2.2.3	 Grey Values vs. Hounsfield Units
		2.3	 Comparison to Multi-­Detector Computed Tomography (MDCT)
		2.4	 Unit Configurations
			2.4.1	 Patient Orientation
			2.4.2	 Functionality
			2.4.3	 Volume Acquisition
		2.5	 Technical Parameters
			2.5.1	 Image Quality
				2.5.1.1	 Spatial Resolution
				2.5.1.2	 Contrast Resolution
				2.5.1.3	 Noise
				2.5.1.4	 Artifacts
				2.5.1.5	 Geometric Accuracy
			2.5.2	 Exposure Parameters
				2.5.2.1	 Equipment-Dependent Factors
				2.5.2.2	 Operator-Dependent Factors
			2.5.3	 Projection Images
			2.5.4	 Rotation Angle
			2.5.5	 Field of View
		2.6	 Future Technical Developments
		References
	3: Image Processing and Visualization Techniques
		3.1	 Introduction
		3.2	 Image Display
			3.2.1	 Understanding CBCT Data
				3.2.1.1	 Reconstruction of the Volumetric Dataset
				3.2.1.2	 Voxel Properties
		3.3	 Visualization
			3.3.1	 Two-Dimensional Techniques
				3.3.1.1	 Orthogonal Sectional Display
				3.3.1.2	 Multi-Planar Reformatting (MPR)
					Curved Planar Reformation
					Oblique Planar Reformation
					Serial Cross-Sectional Reformations
			3.3.2	 Volumetric Techniques
				3.3.2.1	 Variable Thickness Viewing
				3.3.2.2	 Volumetric Rendering
					Indirect Volume Rendering (IVR)
						Shaded Surface Display (SSD)
							Clinical Maxillofacial Applications
					Direct Volume Rendering (DVR)
						Ray Sum Rendering
						Maximum Value (Maximum Intensity Projection)
							Maxillofacial Applications of MIP
						Full-Volume Rendering
						Iso-Surface Rendering
		3.4	 Post-Processing
			3.4.1	 Image Enhancement
				3.4.1.1	 Enhancement Methods
				3.4.1.2	 Image Filters
			3.4.2	 Image Manipulations
		References
	4: Image Quality
		4.1	 Introduction
		4.2	 Resolution
			4.2.1	 Acquired/Reconstructed Spatial Resolution
			4.2.2	 Contrast Resolution
		4.3	 Noise
		4.4	 Artifacts
			4.4.1	 X-ray Beam Related
				4.4.1.1	 Scatter
				4.4.1.2	 Beam Hardening
				4.4.1.3	 Extinction
				4.4.1.4	 Exponential Edge Gradient Effect
			4.4.2	 Patient-Related Artifacts
			4.4.3	 Scanner-Related Artifacts
				4.4.3.1	 Partial Volume Effect
				4.4.3.2	 Sampling Artifacts
				4.4.3.3	 Cone Beam Effect
				4.4.3.4	 Local Tomography
				4.4.3.5	 Offset Projection
			4.4.4	 Clinical Perspective on Artifacts
		References
Part II: CBCT in Daily Clinical Practice
	5: CBCT Use in Daily Practice
		5.1	 CBCT Operation
			5.1.1	 Scan Protocol
				5.1.1.1	 Exposure Factors
					Equipment Dependent
					Operator Controlled
						Effects of Exposure Setting Adjustments
				5.1.1.2	 Acquisition Parameters
					Scan Time
					Relationship Between Scan, Exposure, and Reconstruction Time
					Rotation Angle
					Field-of-View (FOV)
					Resolution
					Calibration
		5.2	 Generic Steps to Optimize Volumetric Data Display
			5.2.1	 Reorient the Data
			5.2.2	 Correct the Data
				5.2.2.1	 Interpolation
				5.2.2.2	 Adjust Contrast and Brightness
				5.2.2.3	 Sharpen the Edges
				5.2.2.4	 Reduce Noise
			5.2.3	 Explore the Data
			5.2.4	 Reformat the Data
				5.2.4.1	 The Radiographic Toolbox
				5.2.4.2	 Task Specific Image Display
		5.3	 Image Analysis
			5.3.1	 Dimensional Accuracy
			5.3.2	 Contrast Accuracy in CBCT
			5.3.3	 Feature Identification Aids
				5.3.3.1	 Inferior Alveolar Canal Tracing
				5.3.3.2	 Volume Measurement
				5.3.3.3	 Virtual Reality
		5.4	 Documentation
			5.4.1	 Interpretation Reports
		5.5	 Practical Dose Reduction Strategies for Maxillofacial CBCT
			5.5.1	 Establish Clinical Necessity
			5.5.2	 Use Patient and Personnel Protection
			5.5.3	 Adjust Device Settings Appropriately
				5.5.3.1	 Adjust Exposure Settings
				5.5.3.2	 Adjust Scanning Parameters
			5.5.4	 Institute a Quality Assurance Program
		References
	6: Ethical and Medicolegal Issues Related to CBCT
		6.1	 Introduction
			6.1.1	 Clinical Case Scenario
			6.1.2	 Standards Define Ethical and Medicolegal Issues Related to CBCT
		6.2	 The Patient
			6.2.1	 Assuring Diagnostic Efficacy
			6.2.2	 Balancing the Possible Benefits vs. the Potential Risks
		6.3	 The Provider
			6.3.1	 Clinical Use Guidelines
			6.3.2	 Practitioner Education
			6.3.3	 Image Interpretation
			6.3.4	 Qualifications for Owning and Operating a CBCT Unit
			6.3.5	 Technical Aspects of CBCT Imaging
				6.3.5.1	 CBCT Acquisition
					Field of View
					Exposure Parameters
				6.3.5.2	 The DICOM File and Image Transfer
					Hard Copy Distribution
					Electronic Data Interchange
						Guidelines for CBCT DICOM Distribution via the Internet
				6.3.5.3	 Radiologic Interpretation
				6.3.5.4	 Teleradiology
			6.3.6	 The Ethical Pitfalls of Self-­Referral for CBCT Imaging
		6.4	 The Dental Industry
		6.5	 The Legal System
			6.5.1	 Equipment Safety Documentation
			6.5.2	 Professional Negligence
			6.5.3	 Professional Liability Insurance
		6.6	 The Payer
		6.7	 Summary
		References
	7: CBCT Quality Assurance
		7.1	 Introduction
		7.2	 CBCT as a Dental or Medical Device
		7.3	 Elements of a QA Program
			7.3.1	 Quality Control (QC)
				7.3.1.1	 Safety System Tests
				7.3.1.2	 X-ray Tube Performance
				7.3.1.3	 Technical Image Quality Evaluation in CBCT
					Spatial Resolution
					Contrast and Noise
					Artifacts
					Geometric Accuracy
				7.3.1.4	 Image Display Tests
				7.3.1.5	 Dosimetry
			7.3.2	 Patient Dose Monitoring
				7.3.2.1	 Diagnostic Reference Levels
			7.3.3	 Clinical Image Quality Assessment
		7.4	 Current QA Guidelines
			7.4.1	 European Commission (SEDENTEXCT)
			7.4.2	 Intersocietal Accreditation Commission (IAC)
		References
	8: Radiation Dose, Risks, and Protection in CBCT
		8.1	 Radiation Dose, Risk, and Protection Considerations
		8.2	 Effects of Ionizing Radiation
			8.2.1	 Stochastic Effects
				8.2.1.1	 The Linear-Non-Threshold Model
				8.2.1.2	 Effect of Age and Gender on Stochastic Risk
			8.2.2	 Deterministic Effects
		8.3	 Radiation Dose
			8.3.1	 Dose Measurement Indices
				8.3.1.1	 Absorbed Dose
				8.3.1.2	 Equivalent Dose (Radiation Weighted Dose)
				8.3.1.3	 Effective Dose
			8.3.2	 Other Dose Metrics
				8.3.2.1	 Computed Tomography Dose Index (CTDI)
				8.3.2.2	 Dose-Area Product
				8.3.2.3	 Other Metrics
		8.4	 Radiation Dose in CBCT
			8.4.1	 Effective Dose
			8.4.2	 Dose Distribution and Organ Doses
			8.4.3	 Cancer Risk
				8.4.3.1	 Comparative Risk
		8.5	 Optimization of Radiation Dose in CBCT
			8.5.1	 Technical Factors
				8.5.1.1	 Field of View Collimation
				8.5.1.2	 Tube Voltage Selection and Beam Filtration
				8.5.1.3	 Tube Current and Exposure Time Selection
			8.5.2	 Shielding
		8.6	 Protection of Workers and the Public
		References
Part III: Regional Maxillofacial Imaging
	9: The Skull
		9.1	 Overview of the Anatomy of the Skull
		9.2	 Topographic Skull Anatomy
		9.3	 Orthogonal Radiographic Anatomy
			9.3.1	 Axial
				9.3.1.1	 Supra-Orbital
				9.3.1.2	 Orbital
				9.3.1.3	 Maxillary Sinus
				9.3.1.4	 Mandibular Ramus
				9.3.1.5	 Mandibular Body
			9.3.2	 Coronal
				9.3.2.1	 Frontal Bone/Mental Protuberance to Infraorbital Rim
				9.3.2.2	 Lateral Orbital Rim/Ostiomeatal Complex
				9.3.2.3	 Posterior Orbit to Posterior Choanae
				9.3.2.4	 Mandibular Ramus/Base of Skull
				9.3.2.5	 Base of Skull/Anterior Cervical Spine
			9.3.3	 Sagittal
				9.3.3.1	 Midsagittal
				9.3.3.2	 Nasal Fossa
				9.3.3.3	 Maxillary Sinus
				9.3.3.4	 Temporal Bone/Mandibular Condyle
	10: The Jaws, Oral Cavity, and Nasopharynx
		10.1	 Introduction
			10.1.1	 The Role of Reformatted Panoramic Imaging
			10.1.2	 A Panoramic Approach to Regional CBCT Anatomy
		10.2	 The Maxilla
			10.2.1	 The Infraorbital Foramen
			10.2.2	 Posterior Superior Alveolar Canal
			10.2.3	 The Maxillary Alveolar Process
			10.2.4	 The Hard Palate
				10.2.4.1	 Nasopalatine Canal
				10.2.4.2	 Greater and Lesser Palatine Canals
		10.3	 The Mandible
			10.3.1	 Mandibular Body
				10.3.1.1	 Anterior Mandible
				10.3.1.2	 Posterior Mandible
					Mandibular Canal
					Mental Foramen
		10.4	 The Oral Cavity and Oropharynx
		10.5	 The Nasopharynx
		References
	11: Neck and Cervical Spine
		11.1	 Introduction
			11.1.1	 Limitations of CBCT Assessment
		11.2	 The Cervical Spine
			11.2.1	 Overview of Radiographic Anatomy
			11.2.2	 The Atlas (C1)
			11.2.3	 The Axis (C2)
			11.2.4	 C3 to C6
			11.2.5	 Specific CBCT Projections
			11.2.6	 Neck and Cervical Spine Evaluation
				11.2.6.1	 Cervical Alignment
				11.2.6.2	 Cranium to the Cervical Spine
				11.2.6.3	 Prevertebral Soft Tissue
			11.2.7	 Skeletal Maturation Assessment
			11.2.8	 Common Incidental Findings of the Cervical Spine
				11.2.8.1	 Ossification Patterns
				11.2.8.2	 Anomalies
				11.2.8.3	 Osteoarthritis
				11.2.8.4	 Muscular, Ligamentous, and Tendon Calcifications
				11.2.8.5	 Foreign Bodies
		11.3	 The Hyoid Bone
		11.4	 Soft Tissues of the Neck
		11.5	 Upper Airway
		References
	12: Anatomy of the Nose and Paranasal Sinuses
		12.1	 Introduction
		12.2	 Anatomic Overview
			12.2.1	 Development
				12.2.1.1	 Paranasal Sinuses
				12.2.1.2	 Nasal Fossa
			12.2.2	 Function of the Nose and Paranasal Sinuses
			12.2.3	 Drainage Pathways
		12.3	 Nasal Cavity
			12.3.1	 Nasal Septum
			12.3.2	 Lateral Wall of the Nose and the Turbinates
		12.4	 Frontal Sinus
			12.4.1	 Frontoethmoidal Complex
		12.5	 Ethmoidal Sinuses
			12.5.1	 The Ostiomeatal Complex (OMC)
		12.6	 Sphenoidal Sinuses
		12.7	 Maxillary Sinuses
		12.8	 Anatomic Variations
			12.8.1	 Aplasia and Hypoplasia
			12.8.2	 Hyperplasia and Pneumatization
				12.8.2.1	 Nasal Fossa
					Nasal Septal Deviation (NSD)
					Paradoxical Middle Turbinate
					Concha Bullosa
					Turbinate Mucosal Hypertrophy
				12.8.2.2	 Paranasal Sinuses
					Frontal
					Ethmoid
					Sphenoid
					Maxillary
			12.8.3	 Additional Variations
				12.8.3.1	 Septae
		References
	13: The Upper Airway
		13.1	 Introduction
		13.2	 Development
		13.3	 Anatomy of the Upper Airway
		13.4	 Regional Anatomy
			13.4.1	 Nasopharynx
				13.4.1.1	 Topographic Features
				13.4.1.2	 Soft Tissue Spaces
			13.4.2	 Oropharynx
			13.4.3	 Hypopharynx
		13.5	 Radiologic Evaluation
			13.5.1	 Key Radiologic Features
			13.5.2	 Clinical Significance
		References
	14: Temporal Bone
		14.1	 Introduction
		14.2	 Development
		14.3	 Imaging Protocol
		14.4	 Anatomy
			14.4.1	 Squamous
			14.4.2	 Tympanic
			14.4.3	 The Styloid Process
			14.4.4	 Petromastoid
				14.4.4.1	 Mastoid
				14.4.4.2	 Petrous
					External Ear
						External Auditory Canal
						Tympanic Membrane
					Middle Ear
						Ossicles
						Compartments of the Tympanic Cavity
						Walls of the Middle Ear Cavity
					Inner Ear
						The Vestibule
						Semicircular Canals
						Cochlea
						Internal Auditory Canal
		14.5	 Normal Anatomic Variants
			14.5.1	 Anatomical Variants Simulating Other Conditions
				14.5.1.1	 Petromastoid Canal
				14.5.1.2	 Cochlear Aqueduct
				14.5.1.3	 Vestibular Aqueduct
				14.5.1.4	 Mastoid Canaliculus
				14.5.1.5	 Inferior Tympanic Canaliculus
				14.5.1.6	 Cochlear Cleft
				14.5.1.7	 The Singular Canal
				14.5.1.8	 Canal for the Superficial Greater Petrosal Nerve
				14.5.1.9	 Superior Petrosal Sinus
				14.5.1.10	 Intrinsic and Extrinsic Fissures
			14.5.2	 Possible Complications from Surgery
				14.5.2.1	 High-Riding Jugular Bulb
				14.5.2.2	 Dehiscent Jugular Bulb
				14.5.2.3	 Bulging Sigmoid Sinus
				14.5.2.4	 Dehiscent Carotid Canal
				14.5.2.5	 Dehiscent Facial Canal
				14.5.2.6	 Koerner’s Septum
				14.5.2.7	 Deep Sinus Tympani
			14.5.3	 Congenital Anomalies
				14.5.3.1	 Large Vestibular Aqueduct
				14.5.3.2	 External Auditory Canal Atresia
				14.5.3.3	 Semicircular Canal Malformations
				14.5.3.4	 Mondini Dysplasia
				14.5.3.5	 Foreign Bodies
					Cochlear Implant
					Ossicular Prosthesis
					Tympanostomy Tubes
			14.5.4	 Common Pathology
				14.5.4.1	 Otitis Externa
				14.5.4.2	 Otitis Media and Mastoiditis
				14.5.4.3	 Cholesteatoma
				14.5.4.4	 Otosclerosis
				14.5.4.5	 Glomus Jugulare Paraganglioma
				14.5.4.6	 Calcified Intracranial Internal Carotid Artery Atheroma (CIICAA)
		References
Part IV: Clinical Applications
	15: Cone Beam Computed Tomography and Maxillofacial Diagnosis
		15.1	 Fundamental Concepts in Diagnostic Radiologic Image Analysis
			15.1.1	 Role of CBCT
			15.1.2	 Considerations Prior to Diagnostic Image Analysis
		15.2	 Analysis of CBCT Images
			15.2.1	 Collect All Available Diagnostic Information
			15.2.2	 Look for the Abnormality
			15.2.3	 Determine the Location of the Abnormality
			15.2.4	 Determine and Describe Key Features of the Abnormality
			15.2.5	 Putting Everything Together
		15.3	 Key Considerations in Radiologic Presentation of Maxillofacial Pathology
			15.3.1	 Low-Density Lesions
			15.3.2	 High-Density Lesions
			15.3.3	 Mixed Density Lesions
				15.3.3.1	 Tooth-Related Mixed Density Pathological Entities
				15.3.3.2	 Mixed Density Jaw Pathology, Not Associated with Teeth
			15.3.4	 Periosteal Reaction
			15.3.5	 The Diagnostic Challenge of the Aggressive Lesion
			15.3.6	 Systemic, Metabolic, and Endocrine Disorders
		References
	16: Incidental Findings on CBCT
		16.1	 Introduction
		16.2	 Incidental Findings on Medical Diagnostic Images
			16.2.1	 Prevalence
			16.2.2	 Significance
		16.3	 CBCT Incidental Findings
			16.3.1	 Prevalence
			16.3.2	 Incidental Findings with Low to Intermediate Clinical Importance
			16.3.3	 Incidental Findings with Potentially High Clinical Importance
				16.3.3.1	 Cystic Lesions and Tumors of the Jaws
				16.3.3.2	 Complete Opacification of the Paranasal Sinuses
				16.3.3.3	 Space Occupying or Destructive Lesions in the Skull Base
				16.3.3.4	 Malignant Lesions in the Head and Neck
				16.3.3.5	 Extracranial Calcified Carotid Artery Atheromatosis (Carotid Artery Calcifications)
				16.3.3.6	 Intracranial Internal Carotid Artery Calcifications
		16.4	 To Report or Not to Report…?
		16.5	 Recommendations for Management
		16.6	 Future Directions
		References
	17: Soft Tissue Hyperdensities
		17.1	 Introduction
			17.1.1	 Etiology of Soft Tissue Hyperdensities
			17.1.2	 Calcifications in the Maxillofacial Region
			17.1.3	 Clinical Significance
			17.1.4	 Radiologic Evaluation
		17.2	 Cranial Vault
			17.2.1	 Physiologic Calcifications
			17.2.2	 Pathologic Calcifications
				17.2.2.1	 Vascular Calcifications
					Intracranial Vertebrobasilar Artery Calcification
					Intracranial Internal Carotid Artery (ICA)
			17.2.3	 Foreign Bodies
		17.3	 Orbit
			17.3.1	 Physiologic Calcifications
			17.3.2	 Pathologic Calcifications
			17.3.3	 Foreign Bodies
		17.4	 Jaws and Adjacent Soft Tissue
			17.4.1	 Pathologic Calcifications
				17.4.1.1	 Sialolithiasis
				17.4.1.2	 Calcified Acne
				17.4.1.3	 Phleboliths
				17.4.1.4	 Heterotopic Ossifications (Bone Formation)
			17.4.2	 Foreign Bodies
				17.4.2.1	 Inserts-Implants (Cosmetic Enhancements)
				17.4.2.2	 Foreign Bodies Due to Accident
		17.5	 Neck and Parapharyngeal Soft Tissues
			17.5.1	 Physiologic Calcifications
				17.5.1.1	 Elongated Styoid Process and Stylohyoid Ligament Calcifications
				17.5.1.2	 Calcification of the Posterior/Anterior Longitudinal Ligaments (Cervical Spine)
				17.5.1.3	 Calcified Triticeous Cartilage
				17.5.1.4	 Calcified Superior Cornu of the Thyroid Cartilage
			17.5.2	 Pathologic Neck and Para-­Pharyngeal Calcifications
				17.5.2.1	 Tonsillar Calcifications (Tonsilloliths)
				17.5.2.2	 Carotid Artery Calcifications
				17.5.2.3	 Calcified Lymph Nodes
			17.5.3	 Foreign Bodies
		References
	18: Applications of CBCT in Orthodontics
		18.1	 The Role of Imaging in Orthodontics
			18.1.1	 The Goals of Imaging in Orthodontics
			18.1.2	 Clinically Based Imaging Selection
		18.2	 The Advantages in CBCT Imaging in Orthodontics
			18.2.1	 Clinical Imaging Efficiency
			18.2.2	 Volumetric Visualization
			18.2.3	 Anatomic Accuracy
			18.2.4	 Data Integration
			18.2.5	 3D Cephalometry
				18.2.5.1 Historical Perspectives
				18.2.5.2 3D Cephalometric Software
				18.2.5.3 Accuracy and Precision of 3D Cephalometry
				18.2.5.4 Types of 3D Cephalometric Analyses
					Summary of 3D Analyses
						3D Analysis of Facial Asymmetry
						Transitioning from 2D to 3D Cephalometry
						Challenges to 3D Cephalometry
					3D CBCT-Based Facial Assessment
			18.2.6	 Virtual 3D Study Casts
			18.2.7	 Predictive Simulations
		18.3	 Specific Indications
			18.3.1	 Dental Structural Anomalies
			18.3.2	 Anomalies in Dental Position
			18.3.3	 Dentoalveolar Morphology
				18.3.3.1 Dental Arch Length and Form Evaluation
			18.3.4	 Dentofacial Deformities and Craniofacial Anomalies
			18.3.5	 Malocclusions, Dental and Skeletal Discrepancies
				18.3.5.1 Facial Asymmetry
			18.3.6	 The Temporomandibular Joint (TMJ)
			18.3.7	 Post-therapy Assessment
				18.3.7.1 Assessment of Alveolar Cleft and Palate Defects
			18.3.8	 Airway Assessment
			18.3.9	 Pathology
				18.3.9.1 Incidental Findings on Orthodontic Patients
			18.3.10 Biomechanical Assessments
				18.3.10.1 Temporary Skeletal Anchorage Device Placement
				18.3.10.2 Biomechanical Modeling
			18.3.11 4D Analysis
		18.4	 Radiographic Imaging Guidelines for Orthodontics
			18.4.1	 Guidelines for the Use of CBCT in Orthodontics
		18.5	 Imaging Protocols
		18.6	 Summary
		References
	19: Orthodontic and Orthognathic Surgery Planning and Simulation Software
		19.1	 Introduction
		19.2	 3-D CBCT-Based Orthodontic and Orthognathic Surgery Diagnosis and Treatment Planning
			19.2.1	 Tooth Development and Relative Position Within the Alveolar Bone
			19.2.2	 Temporomandibular Joint Morphology, Spatial and Functional Relationships
			19.2.3	 Airway Morphology and Respiration
			19.2.4	 Dentofacial Deformities and Craniofacial Anomalies
		19.3	 3-D Image Analysis Procedures for Clinical and Research Assessments
			19.3.1	 Acquisition of 3-D Diagnostic Records
			19.3.2	 Construction of 3-D Volumetric Label Maps (Segmentation)
			19.3.3	 Conversion of 3-D Volumetric Label Maps to 3-D Surface Models
			19.3.4	 Establishment of a Common Coordinate System Across Subjects
			19.3.5	 Image Registration
			19.3.6	 Visualization and Quantification of Changes Overtime
				19.3.6.1	 Visual Analytics with Graphic Display of 3-D Morphological Changes
				19.3.6.2	 Quantitative Measurements
		19.4	 Treatment Planning with Computer-Assisted Surgery (CAS)
			19.4.1	 Treatment Planning and Simulation Software
				19.4.1.1	 Data Acquisition
				19.4.1.2	 Integration of Diagnostic Data
				19.4.1.3	 Image Segmentation
				19.4.1.4	 Virtual Planning and Treatment Simulation
				19.4.1.5	 Quantitative Analysis
				19.4.1.6	 Surgical Guide Design and Fabrication
			19.4.2	 Intraoperative Guidance: Surgical Navigation
				19.4.2.1	 Tracking Technology
		References
	20: Dental Implants
		20.1	 Introduction
			20.1.1	 Dental Implant Components
			20.1.2	 Surgical Approaches
		20.2	 Role of Imaging in Implant Therapy
			20.2.1	 Presurgical Assessment and Planning
			20.2.2	 Perioperative Treatment
			20.2.3	 Postoperative Maintenance
		20.3	 Presurgical Planning Considerations
			20.3.1	 Prosthetic Considerations
				20.3.1.1	 Prosthetic Prerequisites
			20.3.2	 Anatomic Considerations
				20.3.2.1	 Alveolar Bone Morphology
					Assessment
						Alveolar Bone Volume
						Minimal Prosthetic Requirements
						Alveolar Bone Quality
				20.3.2.2	 Anatomic Structures
					Mandible
						Inferior Alveolar Canal (IAC)
						Incisive Canal
						Lingual Canal
						Accessory Canals and Foraminae
						Mental Foramen and Anterior Loop
					Maxilla
						Nasopalatine Foramen and Canal
						Nasal Fossa and Maxillary Sinus
						Specific Considerations for Maxillary Sinus Augmentation
		20.4	 Preoperative Assessment Strategies
			20.4.1	 Software Independent Approach
				20.4.1.1	 Hard and Soft Media
				20.4.1.2	 Provision of Biomodels
			20.4.2	 Software Dependent Assessment
				20.4.2.1	 Implant Planning Software Display Formats
					Creating an Implant Image Series
					The Implant Display Protocol
					Implant Software Display Parameters
				20.4.2.2	 Levels of Software Integration
					Computer-Aided Assessment
					Computer-Assisted Planning
					Computer-Assisted Planning/Computer-
					Computer-Aided Design/Computer-Aided Manufacture (CAD/CAM)
					Image-Guided Surgery and Navigation
		20.5	 Radiographic Templates
		20.6	 Clinical Efficacy of Image-­Guided Implant Therapy
			20.6.1	 Use of Virtual Implant Treatment Planning
			20.6.2	 Use and Fabrication of Static Surgical Guides
		20.7	 Guidelines and Recommendations
		20.8	 Postoperative Assessment
			20.8.1	 Bone Augmentation
			20.8.2	 Implant Complications
				20.8.2.1	 Early Complications
				20.8.2.2	 Late Complications
		References
	21: Planning and Assessment of Bone Reconstruction for Dental Implants
		21.1	 The Edentulous Residual Alveolar Ridge
			21.1.1	 Evaluating and Intercepting Alveolar Bone Resorptive Patterns
			21.1.2	 The Role of Cone Beam Computed Tomography
		21.2	 Materials and Methods Used to Reconstruct the Residual Alveolar Ridge
			21.2.1	 Autogenous Grafts and Bone Substitutes (Allografts, Xenografts, and Alloplasts)
				21.2.1.1	 Tissue Engineering
			21.2.2	 Graft Techniques
				21.2.2.1	 Alveolar Bone Maintenance/Extraction Socket Preservation
					Value of CBCT Imaging
				21.2.2.2	 Horizontal and Vertical Alveolar Ridge Augmentation
					Onlay Block Grafts
					Particulate Grafts
		21.3	 Maxillary Sinus Elevation and Grafting (MSEG)
			21.3.1	 Techniques
			21.3.2	 Presurgical CBCT Assessment
				21.3.2.1	 Surgical Considerations
				21.3.2.2	 Clinical Contraindications
					Relative Contraindications
					Absolute Contraindications
				21.3.2.3	 Graft Simulation
			21.3.3	 Postoperative Radiographic Patterns
				21.3.3.1	 Long-Term Changes in Graft Volume
		21.4	 Immediate Implant Placement
			21.4.1	 Sagittal Root Position
		21.5	 Implant Removal and Alveolar Reconstruction
		References
	22: Endodontic Applications of CBCT
		22.1	 Introduction
		22.2	 Imaging in Endodontics
			22.2.1	 Limitations of Radiographic Intraoral Imaging
			22.2.2	 Advantages of CBCT in Endodontics
			22.2.3	 Challenges of CBCT for Use in Endodontics
				22.2.3.1	 Technical
				22.2.3.2	 Interpretation
		22.3	 Specific Applications
			22.3.1	 Clinical Use Guidelines
			22.3.2	 Clinical Efficacy: Effect on Diagnosis and Treatment Planning
			22.3.3	 Preoperative Assessment
				22.3.3.1	 Tooth Root Anatomy
					Additional Canals and Roots
				22.3.3.2	 Developmental Anomalies
					Dens Invaginatus (Dens in Dente)
					Taurodontism
					Dilaceration
					Gemination/Fusion
				22.3.3.3	 Dental Periapical Pathosis
				22.3.3.4	 Early Radiographic Changes
					Mature Radiographic Presentation
					CBCT Detection
					Residual (Persistent) Periapical Pathosis
				22.3.3.5	 Traumatic Injury
				22.3.3.6	 Root Resorption
					External Root Resorption (ERR)
					Internal Root Resorption (IRR)
				22.3.3.7	 Periapical Non-dental Associated Conditions
					Anatomic Features
					Anomalies
				22.3.3.8	 Tooth-Associated Pathology (Not Necessarily Odontogenic in Origin)
				22.3.3.9	 Maxillary Sinus Disease
					Intrinsic Sinus Disease
					Extrinsic Sinus Disease
			22.3.4	 Intraoperative Applications
			22.3.5	 Postoperative Evaluation
				22.3.5.1	 Outcome Assessment for Select Cases
				22.3.5.2	 Complications Associated with Endodontically Treated Teeth
					Vertical Root Fracture (VRF)
					Perforation
				22.3.5.3	 Endodontic Retreatment Options: Nonsurgical and Surgical
				22.3.5.4	 Dental Implant Therapy
		References
	23: Periodontal Disease
		23.1	 Introduction
		23.2	 Two-Dimensional Imaging
			23.2.1	 Intraoral Radiography
			23.2.2	 Panoramic Radiography
		23.3	 Cone Beam Computed Tomography
			23.3.1	 Advantages in Periodontal Diagnosis
			23.3.2	 Limitations for Periodontal Diagnosis
			23.3.3	 Influences on Periodontal Diagnosis
				23.3.3.1	 Image Acquisition Parameters
				23.3.3.2	 Artifacts
		23.4	 Clinical Applications of CBCT in Periodontics
			23.4.1	 Crestal Alveolar Bone Morphology and Horizontal Bone Loss
				23.4.1.1	 Bone Mapping
			23.4.2	 Localized Intrabony Defects
			23.4.3	 Buccal Cortical Plate Defects
			23.4.4	 Molar Furcation Involvement
			23.4.5	 Surgical Exposure of Maxillary Canines
			23.4.6	 Periradicular Pathology
				23.4.6.1	 External Root Resorption
				23.4.6.2	 Periodontal Abscess
				23.4.6.3	 Lateral Periodontal Cyst
			23.4.7	 Third Molar Pericoronal Pathology
			23.4.8	 Osteomyelitis
			23.4.9	 Combined Periodontic-
			23.4.10 Regenerative Procedures
			23.4.11 Soft Tissue Assessment
		23.5	 Summary
		References
	24: CBCT and the Diagnosis of Temporomandibular Joint Disease
		24.1	 Introduction
			24.1.1	 Role of Diagnostic Imaging
		24.2	 Radiographic Correlative Anatomy of the TMJ
			24.2.1	 The Mandibular Condyle
			24.2.2	 The Glenoid Fossa
				24.2.2.1	 Pneumatization
				24.2.2.2	 Foramen Tympanicum
			24.2.3	 The Interarticular Joint Space
		24.3	 Radiographic Imaging of the TMJ
			24.3.1	 Protocols
				24.3.1.1	 Scan Protocol
				24.3.1.2	 Image Reformatting Protocol
			24.3.2	 Strategies for Image Interpretation
				24.3.2.1	 Individual Elements Within and Between Functional Units
					Condyle
					Glenoid Fossa
				24.3.2.2	 Relationships of the Elements as a Functional Unit
				24.3.2.3	 The Effects of the TMJ Functional Unit on the Maxillofacial Skeleton
			24.3.3	 Characteristics of the Normal Temporomandibular Joint
		24.4	 Disorders of the TMJ
			24.4.1	 Congenital and Developmental Conditions
				24.4.1.1	 Bifid Mandibular Condyle
				24.4.1.2	 Condylar Hyperplasia
				24.4.1.3	 Condylar Hypoplasia
				24.4.1.4	 Coronoid Hyperplasia
			24.4.2	 Condylar Fracture
			24.4.3	 Arthritides
				24.4.3.1	 Degenerative
				24.4.3.2	 Inflammatory
					Rheumatoid Arthritis
			24.4.4	 Cysts and Tumors, Osteomyelitis, and Neoplasia
			24.4.5	 Ankylosis
			24.4.6	 Condylar Resorption
			24.4.7	 TMJ Implants
				24.4.7.1	 CBCT Imaging Protocol and Assessment
			24.4.8	 Periarticular Calcifications
				24.4.8.1	 Synovial Chondromatosis
			24.4.9	 Heterotopic Bone Formation
		References
	25: CBCT Sialography
		25.1	 Introduction
		25.2	 Major Salivary Gland Anatomy
			25.2.1	 Parotid Gland
			25.2.2	 Submandibular Gland
			25.2.3	 Sublingual Gland
		25.3	 Salivary Gland Disease
			25.3.1	 Inflammatory Conditions
			25.3.2	 Space Occupying Conditions
			25.3.3	 Noninflammatory Conditions
		25.4	 Imaging
		25.5	 CBCT Sialography
			25.5.1	 Indications/Contraindications
			25.5.2	 Types of Contrast Agents
			25.5.3	 Technique
			25.5.4	 Adverse Effects
			25.5.5	 Radiation Dose Considerations
		25.6	 CBCT Imaging Patterns
			25.6.1	 Normal Ductal Structure
			25.6.2	 Pathologic Patterns
		References
	26: Image-Guided Surgical Navigation
		26.1	 Introduction
		26.2	 Frame-Based Stereotaxy
		26.3	 Frameless Stereotaxy
			26.3.1	 Pair-Point Registration
			26.3.2	 Surface Registration
			26.3.3	 Planning and Transfer
		26.4	 Specific CBCT Requirements for IGS
			26.4.1	 Field of View
			26.4.2	 Geometric Accuracy
			26.4.3	 Resolution and Contrast
			26.4.4	 Artifacts
		26.5	 IGS for Dental Implants
			26.5.1	 Template-Based Image-
			26.5.2	 Navigation Systems for Image-Guided Implantology
				26.5.2.1	 Accuracy
				26.5.2.2	 Workflow
				26.5.2.3	 Conclusion
		26.6	 Image-Guided Maxillofacial Surgery
			26.6.1	 Intraoperative Imaging
		References
	27: CBCT-Based Image Guidance for Sinus and Skull Base Surgery
		27.1	 Introduction
		27.2	 Imaging in Otolaryngology
			27.2.1	 Emerging Role of CBCT Imaging in ENT
			27.2.2	 Sinus Surgery
				27.2.2.1	 Functional Endoscopic Sinus Surgery
					Complications of Endoscopic Sinus Surgery
				27.2.2.2	 Image-Guided Sinus Surgery
					History
					Accuracy
					Technology Innovations for IGS
		27.3	 Intraoperative Imaging for IGS
			27.3.1	 Does IGS Increase Safety in Sinus Surgery?
			27.3.2	 Other Applications for IGS
		27.4	 Future Directions
		References
	28: Obstructive Sleep Apnea Hypopnea Syndrome
		28.1	 Introduction
		28.2	 Presentation and Predictors of OSAHS
		28.3	 Diagnosis and Treatment
		28.4	 Radiographic Imaging for OSAHS
			28.4.1	 Dynamic Imaging
			28.4.2	 Static Imaging
				28.4.2.1	 Lateral Cephalometric Radiography
				28.4.2.2	 Computed Tomography and Magnetic Resonance Imaging
				28.4.2.3	 Cone Beam Computed Tomography
					Potential Limitations
		28.5	 CBCT Imaging Protocol
			28.5.1	 Reorient the Volumetric Dataset to an Established Orientation Reference Plane
			28.5.2	 Cross-Sectional Assessment
			28.5.3	 Planar Assessment
			28.5.4	 Three-Dimensional Maxillofacial Assessment
			28.5.5	 Regionally Corrected Temporomandibular Joint Images
			28.5.6	 Comparison of Pre- and Posttreatment Effects
			28.5.7	 Dynamic Visualization
		28.6	 Radiographic Image Analysis
			28.6.1	 Lateral Cephalometric
			28.6.2	 Cone Beam CT
				28.6.2.1	 Nasopharyngeal
				28.6.2.2	 Oropharyngeal
					Soft Palatal Dimensions
					Airway Linear Dimensions
					Airway Volume (AV)
					Rostrocaudal Airway Length (RL)
					Airway Shape
		28.7	 Current Status and Future Directions
		References
	29: Dental Impactions
		29.1	 Introduction
			29.1.1	 Dental Eruption Sequence
			29.1.2	 Gubernacular Tract
			29.1.3	 Stages in the Development of the Dentition
		29.2	 Etiology of Dental Impaction
		29.3	 Consequences of Dental Impaction
			29.3.1	 Tooth Resorption
			29.3.2	 Pathology
			29.3.3	 Malocclusion
		29.4	 Imaging Protocols for the Evaluation of Impacted Teeth
			29.4.1	 Third Molars
				29.4.1.1	 Surgical Difficulty of Removal
				29.4.1.2	 Assessment of Third Molar Impactions
					Tooth Orientation and Depth of Impaction
						Mandibular Third Molars
						Maxillary Third Molars
					Relationship to the Adjacent Anatomical Structures
						Maxillary Third Molars
						Mandibular Third Molars
			29.4.2	 Canines
				29.4.2.1	 Assessment of Canine Impaction
					Tooth Location and Orientation
						Maxillary Canines
						Mandibular Canines
					Relationship to the Adjacent Anatomic and Dental Structures
						Maxillary Canines
							Mandibular Canines
			29.4.3	 Premolars
				29.4.3.1	 Mandibular Second Premolar
				29.4.3.2	 Maxillary Second Premolar
			29.4.4	 Supernumerary Impacted Teeth
		References
	30: CBCT Imaging of Sinonasal Disease
		30.1	 Introduction
		30.2	 Overview of Sinus Disease
			30.2.1	 Inflammatory
				30.2.1.1	 Mucositis
					Periapical Mucositis
				30.2.1.2	 Rhinosinusitis
					Acute Rhinosinusitis
					Chronic Rhinosinusitis
						Fungal Sinusitis
						Allergic Sinusitis
					Clinical Considerations of Rhinosinusitis on CBCT Images
						Maxillary Sinusitis of Odontogenic Origin
						Complications of Sinusitis
						Sinus Empyema
						Antroliths
						Extrinsic Periapical Infection and the Maxillary Sinus
			30.2.2	 Neoplasms
				30.2.2.1	 Benign Neoplasms
					Intrinsic Neoplasms
					Extrinsic Neoplasms
				30.2.2.2	 Malignant Tumors
		30.3	 Disease in Other Paranasal Sinuses
		30.4	 Postoperative Maxillary Sinus Changes
			30.4.1	 Sinus Postsurgical Changes
				30.4.1.1	 External Approach Changes
				30.4.1.2	 Functional Endoscopic Sinus Surgery (FESS) Changes
				30.4.1.3	 Surgical Changes Following Maxillary Sinus Elevation and Grafting (MSEG)
					Importance of Membrane Thickness on CBCT Images
					Postoperative Radiographic Patterns
		30.5	 CBCT Imaging Considerations
			30.5.1	 Task Specific Imaging Protocols
				30.5.1.1	 Acquisition Recommendations
					Image Display Recommendations
			30.5.2	 Systematic Interpretation of the Paranasal Sinuses
				30.5.2.1	 Identify Anatomic Features
				30.5.2.2	 Recognize Radiologic Patterns
				30.5.2.3	 Record Maxillary Sinus Opacification
				30.5.2.4	 CBCT Radiologic Criteria for Specialist Referral
		References
	31: CBCT and Additive Manufacturing Technology
		31.1	 Introduction
		31.2	 The AM Sequence
			31.2.1	 Data Acquisition
				31.2.1.1	 Scan Protocol
				31.2.1.2	 Image Preprocessing
				31.2.1.3	 Image Export
			31.2.2	 Computer-Aided Design
				31.2.2.1	 Creation of Image Datasets
				31.2.2.2	 Thresholding and Volume Segmentation
				31.2.2.3	 3D Digital Reconstruction
				31.2.2.4	 Output Format for CAD and AM
		31.3	 AM Processes
			31.3.1	 Vat Photopolymerization
				31.3.1.1	 Stereolithography (SLA)
			31.3.2	 Material Jetting
				31.3.2.1	 Inkjet-Based Processes
				31.3.2.2	 Binder Jetting
			31.3.3	 Material Extrusion
				31.3.3.1	 Fused Deposit Modeling (FDM)
			31.3.4	 Powder Bed Fusion
				31.3.4.1	 Selective Laser Sintering (SLS)
				31.3.4.2	 Direct Metal Laser Sintering (DMLS)
				31.3.4.3	 Electron Beam Melting (EBM)
			31.3.5	 Sheet Lamination
			31.3.6	 Directed Energy Deposition
		31.4	 Comparative Accuracy of AM in OMF Applications
		31.5	 Advantages and Limitations
			31.5.1	 Advantages
			31.5.2	 Limitations
		31.6	 Clinical Indications
			31.6.1	 Cranio-Maxillofacial Surgery
			31.6.2	 Surgical Guide Fabrication
				31.6.2.1	 Surgical Template for Dental Implants
				31.6.2.2	 Craniofacial Surgical Templates
		References