Which statement about enamel is true?

• A. It is primarily organic
• B. It is the hardest tissue
• C. It is resistant to acids
• D. It has high bioactivity

Answer: (B)

Enamel’s extreme hardness comes from its very high mineral content and the organized arrangement of hydroxyapatite crystals into enamel prisms. It’s about 96% inorganic by weight, with tightly packed crystals that resist indentation and wear, making enamel the hardest tissue in the body. This explains why the statement about enamel being the hardest tissue is the correct one.

Enamel being primarily organic is incorrect because its organic portion is minimal. While dental enamel is tough, it isn’t immune to acids: acidic environments can dissolve mineral content and lead to demineralization, so it isn’t truly resistant to acids. And enamel has little to no bioactivity—it doesn’t remodel or respond biologically like other tissues, since it contains no living cells after eruption.