Table 4.

Bone and dentin differences at different scales.

	Bone	Dentin
Tissue scale (millimeters to micrometers)	Bone is an organic matrix of connective tissue composed of cells, fibers, and inorganic matrix ground substance. The cells control the initial production of the mineralized tissue.	Teeth are composed of cells, an organic matrix, and an inorganic matrix.
Microstructure scale (micrometers)	Individual struts (trabeculae) present in the marrow connecting the bone structure, thin plates (lamellae) in the cortical bone, and bone developed around blood veins are all structural units of bone (termed osteons).	Dentinal tubules and the intratubular dentin that surrounds the dentin-forming odontoblasts are structural units of the tooth.
Ultrastructural scale (nanometers)	Tissue components are distinct in the mineral crystals and the organic matrix. The bone’s organic matrix mostly comprises of a fibrous protein, collagen, and trace amounts of other non-collagenous proteins.	Collagen is the primary organic constituent of dentin and cementum. However, there is no collagen present in enamel. An equivalent of the mineral hydroxyapatite is the mineral that reinforces dentin matrices and is also a major constituent of enamel.