Table 5.

Different mineralization phases between the bone and dentin.

Mineralization Phase	Bone	Dentin
First phase	Osteoblasts secrete organic matrix (in particular collagen and non-collagenic proteins) and bone vesicle matrix	Odontoblasts secrete collagen and non-collagenic proteins.
Second phase	Also termed the vesicular phase, vesicles—which have accumulated calcium and phosphorus—begin to nucleate the calcium and phosphorus salts. The crystalline structures grow due to the entry of phosphorus and calcium ions, resulting in the breakage of the vesicle membrane.	Nucleation of vesicles -which have accumulated calcium and phosphorus. The osteoblast elongates a cytoplasmatic process into the dentinal tubules.
Third phase	Termed the fibrillar phase, the hydroxyapatite crystals further increase in the bone extracellular matrix and form the so-called matrix nodules that are associated with the organic matrix of the osteoid substance, in particular with collagen fibrils. It is precisely on the collagen fibers that the hydroxyapatite crystals are deposited, and therefore we speak, in fact, of “collagen mineralization”.	Growth of the crystals occurs. The crystals linked to the collagen fibrils are arranged in rows that conform to the 64 nm striation pattern, with their long axes paralleling the fibril long axes. The progress of general calcification is gradual. Dentin apatite crystals are similar to those found in the bone and cementum, and are 300 times smaller in size than those made in the enamel.