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Why is calcium important for the strength of bones and teeth?

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A labeled diagram of the periodic table entry for calcium, showing its atomic number 20, symbol Ca, atomic weight 40.078, electron configuration, and classification as an alkaline-earth metal. Icons indicate calcium is a solid with a face-centered cubic crystal structure and strongly basic oxides at room temperature. — calcium The chemical element calcium is the most abundant metallic element in the human body.

Calcium is essential for the strength and rigidity of bones and teeth because it serves as a primary structural component of these tissues. Specifically, calcium combines with phosphate to form hydroxyapatite crystals, which are deposited into a collagen matrix through a biological process known as bone mineralization.1234

This mineralization process occurs in two phases:
* Primary mineralization: Specialized cells called osteoblasts secrete a matrix that serves as a site for the rapid deposition of hydroxyapatite crystals, which helps harden the bone tissue.4
* Secondary mineralization: Over months or years, the mineral content and crystal size gradually increase, further enhancing bone density and mechanical strength.4

The resulting mineral-collagen composite functions similarly to two-phase materials like fiberglass, where the rigid, brittle mineral crystals are dispersed within an elastic collagen matrix. This structure provides bones with great compressive strength and the ability to withstand impact, while preventing the propagation of stress failures. Approximately 99 percent of the body's calcium is stored in these mineral deposits, which also act as a reservoir to maintain calcium levels in the blood and other fluids.5627