Enamel elastic moduli

For all mineralized tissues, the environment in which they are tested can significantly affect their mechanical properties. For bone, tests in aqueous and in simulated physiological solutions can change the hardness and elastic modulus by 20% [16, 17]. For enamel and dentin, the difference between the dry and wet mechanical properties can be 10% [18, 19]. Earlier studies [9] found... 

Orthodontics is concerned with tooth movement to optimal positions, using metallic archwires ligated to brackets bonded to enamel or dental restorations by adhesive resins, as well as using suitable other metallic appliances, to provide appropriate forces and bending moments in vivo. The force generated by a bent orthodontic wire is proportional to its elastic modulus, and relatively light and continuous forces are considered to be optimum. There is considerable interest in nickel-titanium orthodontic wires, which have the lowest elastic modulus of the major wire alloys [7]. 

Polycrystalline hydroxyapatite has a high elastic modulus (40 to 117 GPa). Hard tissue such as bone, dentin, and dental enamel are natural composites which contain hydroxyapatite (or a similar mineral), as well as protein, other organic materials, and water. Enamel is the stiffest hard tissue, with an elastic modulus of 74 GPa, and contains the most mineral. Dentin ( = 21 GPa) and compact bone E = 12 to... 

The mechanical properties of the HA are similar to those of the most resistant components of the bone. HA has an elastic modulus of 40-100 GPa, dental enamel 74 GPa, the dentine 21 GPa, the compact bone 18-12 GPa. Nevertheless, dense bulk compact of HA has a mechanical resistance of the order of 100 MPa in front of to the 300 MPa of the human bone, diminishing drastically this resistance in the case of porous bulk compact. 

Huang, T.T., He, L.H., DarendelQer, M.A., Swain, M.V. Correlation of mineral density and elastic modulus of natural enamel white spot lesions using X-ray microtomography and nanoindentation. Acta Biomater. 6, 4553-4559 (2010)... 

Composite Modulus of Elasticity. The modulus of elasticity of the enamel glass—steel composite system has been shown to lie between the modulus of the glass and that of the metal (29). The composite modulus can be calculated by... 

Composite Modulus of Elasticity. The modulus of elasticity of the enamel glass-steel composite system has been shown to lie between the modulus of the glass and that of the metal. The composite modulus can be calculated by Er = ( , - Ef)Q + E where E,. E . and E, are the modulus of elasticity of the composite, the metal, and the enamel, respectively and Q = thickness of the metal divided by total thickness of the composite. 

Some other physical properties of enamel glass are density, from 2.5-3 5 g/mL Mohs hardness. 5-6 tensile strength. 3d-103 MPa (4.900-15.000 psi) compressive strength, 1380-2760 MPa(2-4x It)5 psil, modulus of elasticity. 55-83 GPa (8- 12x I06 psi) and dielectric constant, 5-10. 

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