Tooth Morphology Part 1: Understanding Tooth Structures and Terminology

Tooth morphology is more than just memorizing shapes – it is the language through which we understand the functional design of the human dentition. In this first post of the Tooth Atlas series, we explore the foundational components: anatomical structures, dental directions, and terminology, all presented using the international FDI numbering system.

Labeled anatomical cross-section of a human tooth showing enamel, dentin, pulp, and root structure — Cross-sectional anatomy of a human tooth showing crown, root, and internal structures

✔️ Basic Tooth Anatomy: Crown and Root

Anatomical crown: Part of the tooth covered by enamel.
Anatomical root: Part of the tooth covered by cementum, embedded in the alveolar bone.
Clinical crown/root: Visible/invisible parts depending on gingival level.

⚖️ Surface Terminology

Each tooth has named surfaces based on position and function:

Labial / Buccal: Facial side (labial for anterior, buccal for posterior)
Lingual / Palatal: Tongue side (lingual for mandible, palatal for maxilla)
Mesial: Surface toward the midline
Distal: Surface away from the midline
Occlusal / Incisal: Chewing or cutting edge

Tooth surface directions diagram: labial, lingual, mesial, distal, occlusal — A diagram showing standard dental directional terms used to describe tooth surfaces

↔ Directional Terms

Cervical: Near the gumline
Apical: Toward the tip of the root
Coronal: Toward the top (crown)

🔢 FDI Numbering System

The FDI system uses a two-digit code for each tooth:

First digit: Quadrant (1 to 4 for permanent teeth)
Second digit: Tooth position from the midline (1 to 8)

For example, 11 is the upper right central incisor, and 36 is the lower left first molar.

FDI tooth numbering chart showing permanent teeth in all four quadrants

🔹 Summary: Key Takeaways

Tooth surfaces and directions provide a map of orientation.
Distinguishing between anatomical vs clinical crowns/roots is essential in diagnosis and treatment planning.
The FDI system standardizes tooth identification globally.

🕵️ Coming Next

In Part 2, we explore the incisors – their morphology, distinguishing features, and side identification techniques.

From archived insight to open reflection – a living note of science and thought.