DANB General Chairside Practice Test

The primary component of tooth enamel is hydroxyapatite, which is a crystalline calcium phosphate mineral. Enamel is the hardest substance in the human body and provides a protective outer layer for the teeth. The structure of hydroxyapatite contributes significantly to the durability and strength of enamel, allowing it to withstand the forces of chewing and the acidic environments created by bacterial metabolism in the mouth.

Understanding that enamel consists largely of hydroxyapatite highlights its mineral-based composition rather than organic materials or proteins. For example, collagen protein, while important in other connective tissues, does not form a part of enamel. Similarly, keratin is a fibrous protein found in hair and nails, not in teeth. Calcium carbonate, on the other hand, is a different mineral that plays a role in other biological contexts but is not a major component of enamel. Thus, recognizing hydroxyapatite as the primary constituent underscores the mineral nature of tooth enamel, essential for its protective function.