Proteins of the developing enamel extracellular matrix (such as Amelogenin) control initial mineral deposition (nucleation) and subsequent crystal growth, ultimately determining the physico-mechanical properties of the mature mineralized tissue. Nucleators bring together mineral ions from the surrounding fluids (such as saliva) into the form of a crystal lattice structure, by stabilizing small nuclei to permit crystal growth, forming mineral tissue.[5] Mutations in enamel ECM proteins result in enamel defects such as amelogenesis imperfecta.