Anatomy & Histology · single question
Which dental tissue is composed of approximately 95% inorganic hydroxyapatite crystals, 0.5% organic matrix, and 4.5% water?
Show answer and explanation
Correct answer: D. Enamel
- A. INCORRECT — Dentin is ~70% inorganic HA, ~20% organic (primarily type I collagen), and ~10% water — much less mineralized than enamel.
- B. INCORRECT — Cementum is ~45–50% inorganic HA, ~50% organic matrix and water — less mineralized than both enamel and dentin.
- C. INCORRECT — Pulp is primarily soft connective tissue with minimal inorganic content.
- D. CORRECT — Enamel is the most highly mineralized tissue in the human body, composed of ~96% inorganic hydroxyapatite (HA), ~1% organic matrix, and ~3% water. The values in the question (95%/0.5%/4.5%) closely match enamel composition.
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