Dictionary of terms that show up in dental radiology reports, CBCT equipment manuals, radiation protection regulations and clinical discussions. Use the alphabetical index to jump to any letter.
3
3D viewer
3D visualization mode of the CBCT volume. Allows volumetric rendering (showing densities) or iso-surface (showing the bony surface). Typically with rotation tools, cutting planes, 3D measurements and STL export.
Related terms: Volume rendering · Iso-surface · Marching Cubes
A
Airway
Set of upper respiratory air spaces visible on CBCT with large FOV: nasal cavity, nasopharynx, oropharynx, hypopharynx. Its analysis is relevant in orthodontics, sleep apnea assessment, and obstructive pathology.
Related terms: Cephalometry · Large FOV · Apnea
ALARA— As Low As Reasonably Achievable
Fundamental principle of radiation protection: the dose received by the patient must be the lowest reasonably achievable that still allows obtaining the necessary diagnostic information. In CBCT it is applied by choosing the smallest possible FOV, lower-dose parameters, an appropriate voxel size, and avoiding unnecessary repetitions.
Related terms: Justification · Optimization · Radiation protection
Artifact
Any structure visible on the image that does not correspond to the patient's real anatomy. Common in CBCT: motion artifact (double lines), metallic (streaks from implants/crowns), beam hardening, ring artifact, aliasing, and truncation.
Related terms: Motion · Beam hardening · Truncation
Axial
Horizontal slicing plane, parallel to the floor when the patient is upright. In the viewer you navigate from inferior to superior. It is the original acquisition plane in helical CT and one of the primary viewing planes in CBCT.
Related terms: MPR · Coronal · Sagittal
B
Beam hardening
Artifact produced when the X-ray beam crosses high-density structures (metal, very dense enamel) and lower-energy photons are preferentially absorbed, leaving a "harder" beam. Appears as dark bands adjacent to the dense structure, especially between two metal restorations.
Related terms: Artifact · Metal artifact
C
CBCT— Cone Beam Computed Tomography
Volumetric imaging modality that uses a cone-shaped X-ray beam and a flat-panel detector to obtain a 3D volume of the craniofacial region in a single rotation. Compared to medical CT, it offers lower dose and better spatial resolution for bony tissues.
Related terms: CT · FOV · Voxel
Cephalometry
Study of angular and linear measurements of the skull and face. 2D cephalometry is performed on a lateral telerradiograph; 3D cephalometry is performed on a CBCT volume with large FOV that includes the whole skull. Orthodontics is the main indication.
Related terms: Orthodontics · Telerradiograph · FOV
Coronal
Frontal slicing plane, parallel to the patient's forehead. Divides the body into anterior and posterior portions. In the viewer you navigate from anterior to posterior.
Related terms: MPR · Axial · Sagittal
Crosshair
Lines displayed across axial, sagittal and coronal slices indicating the position of the point of interest in the other planes. Synchronized between views: moving the crosshair in one updates the others to show the corresponding slice.
Related terms: MPR · Synchronization
CT— Computed Tomography
Original medical 3D imaging modality (not dental-specific), based on a fan beam and linear detector. Higher dose than CBCT, better HU quantification, better soft-tissue visualization. In dentistry it is reserved for special cases (extensive tumors, complex craniofacial trauma).
Related terms: CBCT · Effective dose · HU
D
DICOM— Digital Imaging and Communications in Medicine
International standard for the storage, transmission and visualization of medical images. Each DICOM file contains image data and metadata about the patient, equipment and study. Common extensions: .dcm, .dicom, .ima.
Related terms: DICOM viewer · Multiframe · Anonymization
DICOM viewer
Software that allows opening, visualizing and interacting with DICOM files. It can be desktop (installed locally), web (browser) or integrated into PACS systems. Typical features: MPR, measurements, annotations, window/level adjustment and export.
Related terms: DICOM · 3D viewer
DICOM volume
Three-dimensional set of voxels representing the patient's anatomy. In a typical CBCT the volume has between 300³ and 800³ voxels, depending on FOV and voxel size. Stored as DICOM series (one or several files).
Related terms: DICOM · Voxel · MPR
E
Effective dose
Quantity that measures the biological risk of a radiation exposure, weighted by the radiosensitivity of the exposed tissues. Measured in millisieverts (mSv). In dental CBCT it varies between 0.02 mSv (small FOV) and 1 mSv (cephalometric FOV). Annual natural background radiation is ~2.4 mSv.
Related terms: mSv · Sievert · ALARA
Embed
In CBCTHub context, a way to share an anonymized exam through an HTML iframe embedded in another website. Useful for tele-radiology, public second opinions or demonstrations, without revealing patient data.
Related terms: Sharing · Anonymization
Endodontics
Dental specialty that treats pathologies of the pulp and periapical tissues. CBCT is used to identify accessory canals, vertical root fractures, small periapical lesions, perforations and resorptions. Requires small FOV and fine voxel.
Related terms: FOV · Periapical lesion · Spatial resolution
F
FOV— Field of View
Anatomical volume captured by the CBCT equipment in a single acquisition. Typically expressed as diameter × height in centimeters (e.g., 8 × 8 cm). Small FOV = less dose, higher resolution, less coverage. Large FOV = more dose, lower resolution, more coverage.
Related terms: Voxel · ALARA · Indication
G
GDPR— General Data Protection Regulation
European regulation (2016/679) governing the processing of personal data of natural persons in the EU. Applies to any organization processing data of European residents, even outside the EU. Sensitive health data requires explicit legal basis.
Related terms: HIPAA · LGPD · Sensitive data
H
HIPAA— Health Insurance Portability and Accountability Act
US law from 1996 governing the handling of protected health information (PHI). Applies to clinics, hospitals, laboratories and their technology providers (Business Associates). Includes privacy, security and breach notification rules.
Related terms: GDPR · LGPD · PHI
HU— Hounsfield Units
Units measuring radiographic density used in CT and, partially, in CBCT. Water is defined as 0 HU, air as -1000 HU, cortical bone between +1000 and +2000 HU. In CBCT values are less reliable than in medical CT (not rigorously calibrated), but useful as comparative reference for assessing bone quality (Misch D1-D4 classification).
Related terms: Bone density · Misch · CT
I
IAN— Inferior Alveolar Nerve
Nerve that runs through the mandibular canal and exits through the mental foramen. It innervates the lower teeth, mandible, labial mucosa and chin. Its tracing on CBCT is essential to safely plan posterior implants and third molar surgery.
Related terms: Mandibular canal · Mental foramen · Implant
Implant
Titanium (or other material) fixture surgically placed in the maxillary or mandibular bone to replace the root of a lost tooth. CBCT planning allows measuring height, thickness and bone quality, as well as distances to critical anatomical structures.
Related terms: Implantology · IAN · Sinus lift
Inferior alveolar nerve
See IAN. Its damage during surgery produces lip and chin paresthesia. Always verify its position on CBCT before posterior lower implants and impacted third molar extractions.
Related terms: IAN · Mandibular canal · Mental foramen
J
Justification
First principle of radiation protection: no study is performed if its net benefit does not compensate for the potential harm. Every CBCT must be justified by a documented clinical indication.
Related terms: ALARA · Optimization · Indication
K
kVp— Peak kilovoltage
Maximum voltage applied to the X-ray tube. Determines the energy of the beam photons: higher kVp = greater penetration. Typically 80–120 kVp in dental CBCT. Modifying it affects both image quality and dose.
Related terms: mAs · Parameters
L
LGPD— Lei Geral de Proteção de Dados
Brazilian general data protection law (2018), analogous to the European GDPR. Regulates the processing of personal data of natural persons in Brazil, including sensitive health data. Applies to clinics and imaging centers operating in Brazil.
Related terms: GDPR · HIPAA · Sensitive data
M
Mandibular canal
Bony canal inside the mandible that houses the inferior alveolar nerve, artery and vein. Its location is critical in planning posterior lower implants and extracting third molars. On CBCT it appears as a hypodense line with corticated walls.
Related terms: Inferior alveolar nerve · Implant · IAN
Marching Cubes
Classic 3D visualization algorithm that extracts an isovalue surface (iso-surface) from a scalar volume. In CBCT it is used to generate 3D meshes of the bony skeleton from the DICOM volume, exportable as STL for printing or surgical planning.
Related terms: Iso-surface · STL · 3D View
mAs— Milliampere-seconds
Product of tube current (mA) by exposure time (seconds). Determines the number of photons generated. Higher mAs = more photons = better signal-to-noise ratio but higher patient dose.
Related terms: kVp · Dose · Parameters
Maxillary sinus
Pneumatized cavity (filled with air) inside the maxillary bone, located above the upper posterior teeth. Its assessment on CBCT is critical before upper posterior implants: if remaining bone height is insufficient, sinus lift may be required.
Related terms: Sinus lift · Upper posterior implant
MIP— Maximum Intensity Projection
Visualization mode that, for each pixel, projects the maximum intensity value found along the line of sight, within a slab of configurable thickness. Useful to visualize hyperdense structures (bones, vascular contrast) and simulate panoramic view.
Related terms: Reconstructed panoramic · Slab · TMJ
Misch (classification)
Bone density classification developed by Carl Misch for implantology, categorizing bone into D1 (dense cortical), D2 (thick cortical with dense trabeculae), D3 (thin cortical with porous trabeculae) and D4 (fine trabecular). It correlates approximately with HU values on CBCT.
Related terms: Bone density · HU · Implantology
MPR— Multi-Planar Reconstruction
Technique that allows visualizing the DICOM volume in any arbitrary plane (axial, sagittal, coronal or oblique) from a single acquisition. The main visualization mode in CBCT.
Related terms: Axial · Sagittal · Coronal · Oblique
mSv— Millisievert
Unit of effective dose. 1 mSv = 0.001 Sv. Annual natural background radiation is ~2.4 mSv. A dental CBCT varies between 0.02 and 1 mSv depending on FOV and equipment. A medical head CT is ~2 mSv.
Related terms: Effective dose · Sievert
Multiframe
Variant of the DICOM standard in which a single .dcm file contains all frames (slices) of the volume, instead of having one separate file per slice. Reduces the number of files to manage but requires compatible viewers.
Related terms: DICOM · Volume
O
Oblique
Arbitrary slicing plane that is neither axial, sagittal nor coronal. Useful to align with anatomical structures that don't follow orthogonal axes (inclined dental roots, root canal trajectories, TMJ). Adjusted in the viewer by rotating a free plane on the three axes.
Related terms: MPR · TMJ · Endodontics
P
PACS— Picture Archiving and Communication System
Centralized system for storing, retrieving, distributing and visualizing medical images. Common in hospitals and large imaging centers. CBCTHub can integrate via DICOM as an external system.
Related terms: DICOM · Viewer
Panoramic radiograph
2D radiograph showing both jaws, teeth and adjacent structures in a single flat image. Lower-dose modality than CBCT (~0.01–0.02 mSv) and first line for many diagnostic indications. CBCT is reserved when the panoramic is not diagnostic.
Related terms: Telerradiograph · Bitewing · CBCT
PHI— Protected Health Information
Information protected under HIPAA. Includes any identifiable information related to a person's health status: name, date of birth, insurance number, medical images, diagnoses, treatments.
Related terms: HIPAA · Sensitive data
Pixel vs voxel
Pixel: minimum unit of a 2D image (square). Voxel: minimum unit of a 3D volume (cube). In CBCT, each voxel has an intensity value and a physical size (e.g., 0.2 mm × 0.2 mm × 0.2 mm). Smaller voxel = higher spatial resolution.
Related terms: Voxel · Resolution
R
Reconstructed panoramic
Panoramic image generated from the CBCT volume following a mandibular curve drawn by the user. Allows visualizing all teeth of an arch in a single image, similar to a classic panoramic but without additional radiation.
Related terms: Curve · Cross-sectional slices · MIP
S
Sagittal
Vertical slicing plane parallel to the body's mid-sagittal plane. Divides the patient into right and left portions. In the viewer you navigate from right to left.
Related terms: MPR · Axial · Coronal
Sinus lift
Surgical technique that increases the available bone height in the upper posterior sector, separating the sinus membrane from the floor and filling with graft material. Planned with CBCT measuring remaining bone height, presence of sinus septa, and membrane status.
Related terms: Maxillary sinus · Implant · Schneider membrane
STL— Stereolithography
Standard file format for representing 3D meshes through triangles. Generated from CBCT (iso-surface via Marching Cubes) or intraoral scanners. Used for 3D printing, CAD software and surgical planning.
Related terms: Marching Cubes · 3D View · 3D printing
T
Telerradiograph
2D radiograph of the skull in lateral position (lateral telerradiograph) or frontal (PA telerradiograph). Typical focus-patient distance of 1.5 m to minimize magnification. Used in 2D orthodontic cephalometry.
Related terms: Cephalometry · Orthodontics
TMJ— Temporomandibular Joint
Joint between the mandibular condyle and the temporal bone. CBCT allows assessing condylar morphology, joint space, degenerative changes and asymmetries. The first-line indication in disc dysfunction is usually MRI.
Related terms: Condyle · Glenoid fossa · MRI
Truncation
Artifact that appears when the FOV is not large enough to include all the tissues the X-ray beam passes through. Results in dark or bright bands at the image edges, particularly noticeable in upper and lower axial slices.
Related terms: Artifact · FOV
V
Volume rendering
3D visualization of the entire volume by assigning colors and opacities to voxels according to their intensity (typically using a transfer function). Allows simultaneous viewing of bone, soft tissue and air.
Related terms: 3D View · Iso-surface
Voxel
Volume Element. Minimum unit of 3D volume, equivalent to the pixel in 2D imaging. In CBCT it is measured in millimeters (typically 0.075 to 0.4 mm side). Small voxel = higher spatial resolution but more dose and larger files.
Related terms: Pixel · FOV · Spatial resolution
W
WebAssembly— WASM
Technology that allows running compiled code (C++, Rust) directly in the browser at near-native speed. CBCTHub processes DICOM files with WebAssembly: pixels never reach the server, all processing happens on the user's device, ensuring privacy.
Related terms: Local processing · Privacy
Window Level (WL/WW)
Brightness and contrast adjustment in medical imaging. WW (Window Width) controls the range of HU values displayed; WL (Window Level / Center) controls the center of that range. Typical presets: bone (WW 2000, WL 400), soft tissue (WW 350, WL 40).
Related terms: HU · Brightness · Contrast
Missing a term?
This glossary is updated regularly. If you miss a key term or want to suggest an improvement to a definition, write to support@cbcthub.com.