Dental Biomaterials I - Mechanical Properties

A group of properties in dental materials that describe how materials react to forces.

An external action that causes or tends to cause movement of a body.

The unit of force is Kg , Pound (Ib) or Newton (N).

Internal reaction to an external force, equal in magnitude but opposite in direction.

Stress is measured in units of force per unit area (e.g., N/m^2, MPa).

Stress that results from forces pushing inward on a body, tending to shorten it.

The stress at which a material starts to deform permanently, deviating from the linear stress-strain relationship.

The maximum stress a material can withstand before fracturing.

The stress at which a material fractures.

Measures a material's stiffness. It's the ratio of stress to strain in the elastic region.

A graphical representation of how a material deforms under stress.

The stress value beyond which stress and strain aren't linearly related.

Stress is directly proportional to strain up to the proportional limit.

Measure of deformation of a material under stress.

Force per unit area applied to a material.

A measure of a material's stiffness or rigidity; also known as Young's modulus.

A material's ability to deform elastically with little stress; the opposite of stiffness.

A material's ability to be drawn into wires without breaking.

A material's ability to be hammered or shaped into thin sheets without breaking.

A measure of ductility by calculating percentage change in length after a tensile test.

A pulling force exerted on a material.

A test to evaluate a material's ductility in bending and toughness.

Force per unit area applied to a material, often measured in a material test.

The ability of a material to be hammered or rolled into thin sheets without breaking.

The ability of a material to be drawn into wires without breaking.

The tendency of a material to fracture without significant deformation.

Ability to absorb energy without permanent deformation.

Ability to absorb energy and resist fracture.

Shows how a brittle material deforms under stress, with little or no plastic deformation.

Resistance of a material to forces pushing inward, tending to shorten it.

Resistance of a material to forces pulling apart, tending to lengthen it.

A material property indicating resistance to scratching and ease of finishing.

The amount of energy needed to initiate and propagate a crack in a brittle material under stress.

Soft wax surfaces scratch easily, impacting restoration accuracy.

Glass particles in composite resin stop crack propagation, increasing fracture toughness.

Zirconia particles absorb energy needed for crack propagation, thus increasing porcelain's fracture toughness.

High co-Cr denture hardness maintains a mirror finish but makes finishing/polishing more difficult.

Porcelain restorations (harder) should not contact natural teeth (softer) to prevent wearing.

Material's resistance to indentation, penetration, or scratching.

Loss of material due to mechanical action, often undesirable, but helpful in finishing.

Use soft-bristled brushes for denture cleaning to avoid scratching or damaging the denture.

Hard materials are preferred for model and die materials to prevent scratching during wax pattern creation.

Normal wear of teeth during chewing.

Wear from aggressive tooth brushing.

Hardness affects the ease and resistance to scratching during finishing and polishing of a material.

Wear due to excessive stress or habits like bruxism.

High hardness of co-cr denture-base is good for maintaining its mirror-like surface, but makes finishing/polishing more challenging.

Natural teeth are less hard (KHN 340) than porcelain teeth (KHN 460). This difference can result in abrasion and damage when they are in contact.

Wear from acidic substances like drinks or stomach acid, affecting tooth enamel.

Resistance to movement between materials.