How does mineralization proceed in enamel compared to dentin?

• A. Dentin and enamel mineralize simultaneously from the same matrix.
• B. Dentin mineralizes first from predentin; enamel mineralizes later from secreted enamel matrix by ameloblasts.
• C. Enamel mineralizes first from ameloblast-derived dentin matrix; dentin mineralizes after eruption.
• D. Enamel mineralizes before dentin; dentin mineralizes after eruption.

Answer: (B)

Dentin mineralization happens first, followed by enamel. Odontoblasts lay down predentin along the pulp–dentin border, and predentin then mineralizes to form dentin. Only after dentin formation begins do ameloblasts start secreting enamel matrix. Enamel mineralizes within that secreted enamel matrix produced by ameloblasts, producing the hard enamel later in development. This sequence—dentin from predentin first, then enamel from secreted enamel matrix—explains why dentin mineralizes before enamel.