Enamel compressive strength

Mechanical Properties of Candidate Materials. The mechanical properties of enamel and dentin were presented earlier in Table 5.14. We will use these values as the basis for our material selection process. Of these properties, compressive strength is the most important. The candidate material should have a compressive strength at least that of enamel, which is about 384 MPa. 

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. 

Dental composites have a Young s modulus in the range 10 to 16 GPa, and the compressive strength from 170 to 260 MPa [Cannon, 1988]. As shown in Table 41.1, these composites are still considerably less stiff than dental enamel, which contains about 99% mineral. Similar high concentrations of mineral particles in synthetic composites cannot easily be achieved, in part because the particles do not pack densely. Moreover, an excessive concentration of particles raises the viscosity of the unpolymerized paste. An excessively high viscosity is problematical since it prevents the dentist from adequately packing the paste into the prepared cavity the material will then fill in crevices less effectively. 

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