Lecture 02
Tooth Macro and Micro Anatomy
Crown & Root Anatomy · Tooth Tissues · Surfaces · Landmarks · Divisions into Thirds
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10 محاضرات كاملة + مراجعة ميدتيرم وفاينل
اشترك مرة واحدة بـ 300 جنيه وافتح الترم كامل
اشترك الآن
🦷 Macro-anatomy of the Tooth
Anatomical Crown
Covered by enamel, up to the CEJ
Clinical Crown
Portion visible in the mouth, above the gingival margin
Root
Covered by cementum, from the CEJ to the apex
Pulp
Living soft tissue — nerves and blood supply
CEJ (Cementoenamel Junction): the boundary where enamel meets cementum — divides the anatomical crown from the root.
🧱 Tooth Tissues
| Tissue | Key Feature |
|---|---|
| Enamel | Hardest substance in the body. Avascular, no nerves, cannot regenerate |
| Dentin | Forms the bulk of the tooth. Contains dentinal tubules — responsible for sensitivity |
| Cementum | Covers the root. Attaches to bone via Sharpey's fibres of the PDL |
| Pulp | Connective tissue — nerves, blood vessels, odontoblasts — responsible for vitality |
🧭 Tooth Surfaces
Anterior Teeth
Labial (lip) · Lingual/Palatal (tongue/palate) · Mesial (toward midline) · Distal (away from midline) · Incisal (biting edge)
Posterior Teeth
Buccal (cheek) · Occlusal (chewing surface) — plus Mesial, Distal, Lingual
⛰️ Crown Landmarks — Elevations
- Cusp: pointed elevation; a pulp horn lies beneath it — removing a cusp can affect the pulp
- Tubercle: small enamel elevation — can be removed WITHOUT affecting the pulp
- Ridge: linear elevation — marginal, triangular, transverse, oblique, cusp, or buccal
- Cingulum: convex prominence on the lingual surface of anterior teeth, at the cervical third
- Mamelons: 3 rounded eminences on the incisal edge of newly erupted incisors — wear away with use
Exam tip: Cusp removal affects the pulp (pulp horn beneath it). Tubercle removal does NOT.
🕳️ Crown Landmarks — Depressions
- Developmental groove: shallow groove marking the junction between two developmental lobes
- Fissure: imperfect fusion at the base of a developmental groove — highly caries-prone
- Pit: small depression at the junction of two or more developmental grooves
- Fossa: concave depression — lingual fossa (anteriors); triangular/central fossa (posteriors)
- Sulcus: broad shallow valley between cusps — the floor is a groove
📐 Line Angles, Point Angles & Divisions into Thirds
- Line angle: junction of two tooth surfaces — named by combining both surface names
- Point angle: junction of three tooth surfaces — named by combining all three
- Transverse ridge: buccal triangular ridge + lingual triangular ridge of opposing cusps meeting across the occlusal surface
Cervicoincisally
Cervical, middle, incisal thirds
Mesiodistally
Mesial, middle, distal thirds
Labiolingually
Labial, middle, lingual thirds
TOOTH ANATOMY & LANDMARKS
🦷 Macro-anatomy
Anatomical crown — enamel
Clinical crown — visible
Root — cementum
CEJ = dividing landmark
🧱 Tooth Tissues
Enamel — hardest, no regen
Dentin — bulk, tubules
Cementum — root cover
Pulp — vitality
⛰️ Elevations
Cusp — affects pulp
Tubercle — enamel only
Ridge — linear
Cingulum — lingual anterior
Mamelons — 3 on new incisors
🕳️ Depressions
Dev. groove
Fissure — caries-prone
Pit
Fossa
Sulcus
1
Hardest Tissue
Enamel = hardest substance in the body. Avascular, no nerves, cannot regenerate.
2
Cusp vs Tubercle
Cusp removal affects the pulp (pulp horn beneath); tubercle removal does NOT.
3
Mamelons
3 eminences on newly erupted incisal edges — wear off with use.
4
Fissures
Faults in developmental grooves — the most caries-prone areas of the tooth.
5
Cingulum
Lingual bulge at the cervical third of anterior teeth — the lingual developmental lobe.
6
Transverse Ridge
Buccal + lingual triangular ridges crossing the occlusal surface buccolingually.
7
Dentinal Tubules
Found in dentin — responsible for tooth sensitivity.
8
Sharpey's Fibres
Connect cementum to alveolar bone via the periodontal ligament (PDL).
9
Point Angle
Junction of 3 surfaces — named by combining all three surface names.
10
Occlusal Surface
Found only on posterior teeth — the chewing surface.
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★ ★ ★ ★ ★
حاجة واحدة بس 🌟
أول لكتشر anatomy بييجي محمّل بأسماء غريبة كتير، وده طبيعي — مش حد بيحفظها من أول مرة.
اللي بيفرق هو إنك تربط كل اسم بصورة أو وظيفة، مش تحفظه لوحده. عشان كده كل محاضرة هنا فيها خريطة ذهنية قبل الحفظ، مش بعده.
جرّب المحاضرة دي وشوف الفرق بنفسك.
🦷 Crown & Root Anatomy
Crown & Root
Anatomical vs Clinical Crown & Root
The gingival margin is the boundary between clinical crown and clinical root, while the CEJ divides the anatomical crown from the anatomical root.
- Anatomical crown = covered by enamel
- Clinical crown = visible above gingiva
Tissues
Single-Rooted Tooth — Tissue Layers
Crown is enamel-covered; root is cementum-covered — both surround the dentin and pulp inside.
🧭 Tooth Surfaces — All 6 Directions
Surfaces
Labial, Buccal, Mesial, Distal, Occlusal, Lingual
A classic HIGH-YIELD labeled diagram showing every surface direction used to describe tooth anatomy.
- Mesial = toward the midline
- Distal = away from the midline
- Occlusal only exists on posterior teeth
📐 Divisions into Thirds
Thirds
Cervical / Middle / Incisal Thirds
Anterior teeth are divided cervicoincisally and mesiodistally into thirds — a key reference system used throughout dental anatomy.
📏 Line Angles & Point Angles
Posterior
Line Angles — Posterior Tooth
Each line angle is named by combining the two surfaces that meet at it.
Anterior
Line Angles — Anterior Tooth
Labioincisal, Linguoincisal, Mesiolabial, Distolabial — line angles unique to anterior tooth morphology.
Point Angles
Point Angles — Junction of 3 Surfaces
Point angles are named by combining all three meeting surface names.
⚠️ Exam Trap: Cusp removal affects the pulp because a pulp horn lies beneath it. Tubercle removal does NOT — it's purely enamel. Don't mix these up in MCQs.
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