Mechanical Properties Of Dental Materials Notes

Mechanical Properties Of Dental Materials

• Stress: Force per unit area within a structure subjected to an external force on pressure.
• Shear stress: Ratio of force to the original cross-sectional area parallel to the direction of the force applied to a test specimen.
• Tensile stress: Ratio of tensile force to the original cross-sectional area perpendicular to the direction of applied force
• Compressive stress: Ratio of compressive force to cross-sectional area perpendicular to the axis of applied force
• Strain: Change in length per unit initial length.
• Elastic Strain: Deformation that is recovered upon removal of an externally applied force or pressure.
• Plastic strain: Deformation that is not recoverable when the externally applied force is removed
• Strength: Maximum stress that a structure can withstand without sustaining a specific amount of plastic strain or stress at the point of fracture.
• Tensile strength: Tensile stress at the point of fracture.
• Yield strength: The stress at which a test specimen exhibits a specific amount of plastic strain.
• Compressive strength: Compressive stress within a compression test specimen at the point of fracture.

• Elastic modulus or Young’s modulus: Relative stiffness of material or ratio of elastic stress to elastic strain.
• Proportional limit: Maximum stress at which stress is directly proportional to strain and above which plastic deformation occurs.
• Resilience: The relative amount of elastic energy per unit volume released on unload- ing of a test specimen
• Ductility: Relative ability of a material to deform plastically under tensile stress before it fractures.
• Malleability: Ability of a material to sustain considerable permanent deformation without rupture under compressions as in hammering or rolling into a sheet. Gold is the most ductile and malleable pure metal., 2nd silver.
• Brittleness: Relative to the ability of a material to deform plastically.
• Hardness: Resistance of a material to plastic deformations typically measured under an indentation load.
• Toughness: Ability of a material to absorb elastic energy to deform plastically before Fracturing.
• Average max. sustainable biting force is approximately 756 N (170 Pounds)

Classification: based on:

Hard ness:

Compressive strength:

Linear coefficient of thermal expansion(X10-6/0c)

Melting Points