Topics

Topic

design image
Teeth

Teeth are mineralized, calcified structures embedded within the alveolar processes of the maxilla and mandible. They are essential components of the oral cavity and are composed of highly specialized tissues adapted for durability and sensory function. Teeth are closely related to the jaws, gingiva, periodontal structures, and adjacent facial bones, making them central to dental, maxillofacial, and radiologic evaluation.

Humans develop two dentitions—deciduous (primary) and permanent—each with characteristic morphology, number, and imaging appearance.

Synonyms

  • Dentition

  • Dental structures

Location

  • Situated within the alveolar sockets of the maxilla and mandible

  • Arranged in dental arches (upper and lower)

  • Upper teeth: Embedded in the maxillary alveolar process

  • Lower teeth: Embedded in the mandibular alveolar process

  • Surrounded by gingiva and periodontal ligament

  • Closely related to the maxillary sinus (posterior maxillary teeth)

Types of teeth

  • Incisors: Central and lateral, cutting edges

  • Canines: Single-cusped, tearing function

  • Premolars: Bicuspid teeth for crushing

  • Molars: Multicuspid teeth for grinding

Anatomical components

  • Crown:

    • Visible portion above the gingiva

  • Neck (cervix):

    • Junction between crown and root

  • Root:

    • Portion embedded in the alveolar bone

Tissue composition:

  • Enamel:

    • Hardest substance in the body, covers the crown

  • Dentin:

    • Forms the bulk of the tooth beneath enamel and cementum

  • Cementum:

    • Covers the root surface

  • Pulp:

    • Central soft tissue containing nerves and vessels

Relations

Externally:

  • Gingiva and oral mucosa

  • Lips and cheeks

  • Tongue (lingual aspect)

Osseous relations:

  • Alveolar bone of maxilla and mandible

  • Maxillary sinus (upper premolars and molars)

  • Inferior alveolar canal (lower molars and premolars)

Neurovascular relations:

  • Superior and inferior alveolar nerves

  • Alveolar branches of maxillary and mandibular arteries

Dentition

  • Deciduous (primary) teeth:

    • 20 teeth

    • Erupt from ~6 months to 2.5 years

  • Permanent teeth:

    • 32 teeth (including third molars)

    • Replace deciduous teeth and erupt from ~6 years onward

X-ray appearance

Intraoral radiographs / panoramic radiograph (OPG):

  • Enamel: Highly radiopaque

  • Dentin and cementum: Slightly less radiopaque than enamel

  • Pulp cavity: Radiolucent central area

  • Roots: Well-defined within alveolar bone

  • Periodontal ligament space: Thin radiolucent line

  • Lamina dura: Thin radiopaque line outlining the socket

CT appearance

Non-contrast CT:

  • Enamel: Very high attenuation

  • Dentin and cementum: High attenuation

  • Pulp chamber and root canals: Low attenuation

  • Alveolar bone: Clearly defined cortical and cancellous components

  • Tooth–sinus relationship: Well visualized for maxillary posterior teeth

Post-contrast CT:

  • Dental hard tissues: No enhancement

  • Pulp and surrounding soft tissues: May enhance depending on vascularity

3D CT VRT appearance

Volume-rendered technique (VRT):

  • Teeth: Bright, sharply defined structures

  • Crown morphology: Clearly visualized cusps and incisal edges

  • Root anatomy: Length, curvature, and number of roots well demonstrated

  • Dental arches: Accurate depiction of alignment and spacing

  • Clinical utility: Preoperative planning and anatomical assessment

MRI appearance

T1-weighted images:

  • Enamel and dentin: Very low signal intensity

  • Pulp: Intermediate to high signal due to fat and vascular content

  • Surrounding marrow: Intermediate signal

T2-weighted images:

  • Hard dental tissues: Low signal

  • Pulp: High signal intensity

  • Periodontal soft tissues: Intermediate-to-high signal

CT VRT 3D image

Teeth 3D

CT image

Teeth CT

X Ray image

Teeth X RAY anatomy image -img-00000-00000