Term
| What are the 4 properties of materials? |
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Definition
-physical
-mechanical
-chemical
-biologic |
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Term
| What are physical properties? |
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Definition
| properties based on the laws of physics (mass, energy, force, light, heat) |
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Term
| What are chemical properties? |
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Definition
| setting reactions, decay & degradation |
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Term
| What are mechanical properties? |
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Definition
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material’s ability to resist forces |
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Term
| What are biologic properties? |
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Definition
| effects materials have on living tissue |
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Term
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Definition
| The amount of mass of material in a given volume |
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Term
| Describe boiling and melting points. |
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Definition
| Atomic bonds between molecules are broken by thermal energy. Some materials do not melt but decompose (wood) |
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Term
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Definition
| Measure of a liquid’s tendency to evaporate and become a gas. Materials with high vapor pressure evaporate quickly and are useful as solvents. |
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Term
| What is thermal conductivity? |
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Definition
| The rate of heat flow through a material. |
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Term
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Definition
| Measure of the amount of thermal energy that a material can hoard. |
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Term
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Definition
| Amount of energy required to melt a material. |
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Term
| What is heat of vaporization? |
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Definition
| Amount of energy required to boil a material. |
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Term
| Explain coefficient of thermal expansion. |
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Definition
| Measure of the change in volume in relation to the change in temperature. |
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Term
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Definition
| Materials shrink when cooled, expand when heated. Opening and closing of the gap between a restoration and tooth surface which results in microleakage, tooth sensitivity, and recurrent decay. |
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Term
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Definition
| Electricity flowing from the fork to the amalgam resulting in stimulation of pulp |
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Term
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Definition
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Term
| Low viscosity= BLANK wetting |
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Definition
| Low viscosity= GOOD wetting, low contact angle of a liquid on a solid allows for bonding |
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Term
| How is hardness measured? |
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Definition
| Measured by the indentation of a tip of a special instrument. |
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Term
| What is a durometer test? |
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Definition
| Measures how deep a steel ball will sink when pressed in surface of soft material. |
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Term
| What is another word for abrasion resistance? |
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Definition
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Term
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Definition
| Amount of material that dissolves in a liquid |
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Term
| Does dental cement need to have high or low solubility? Why? |
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Definition
| Dental cement needs to have low solubility or increased recurrent decay will occur. |
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Term
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Definition
| ability to absorb water, will swell |
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Term
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Definition
| fundamental color of an object |
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Term
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Definition
| color saturation or strength of hue |
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Term
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Definition
| light or darkness of a color |
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Term
| What is fluorescence? What can inadequate fluorescence cause? |
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Definition
-fluorescence- the interaction of teeth and dental materials with UV light, fluorscent light=black light
-Inadequate fluorescence will make some dental materials look dark or glow |
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Term
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Definition
| weight or load applied to an object |
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Term
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Definition
| the ability to change in shape and return to original shape |
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Term
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Definition
| the force that develops in a loaded object |
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Term
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Definition
| Elongation of a loaded object that is measured by the change in length divided by the original length |
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Term
| What is the modules of elasticity? |
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Definition
-MOE = stress/strain
-High modulus of elasticity the stiffer the material. (enamel) |
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Term
| What is elastic deformation? |
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Definition
| Initial change in length when a stress is removed and an object returns to its original length |
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Term
| WHat is permanent deformation? |
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Definition
| Object becomes permanently stretched out |
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Term
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Definition
| Pushing or crushing stress |
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
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Definition
| compression and tension forces |
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Term
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Definition
Ratio of the strain in the direction of the stress to the strain in a direction perpendicular to the stress
(distortion in more than 1 direction ) |
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Term
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Definition
| Ability of absorb energy and not become deformed |
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Term
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Definition
| Energy absorbed up to the failure point |
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Term
| What is fracture toughness? |
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Definition
| Measure of the energy required to fracture a material when a crack is present (porcelain) |
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Term
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Definition
| Material failure after having been stressed repetitively for a long time |
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Term
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Definition
| Small change in shape that results when an object is under continuous compression |
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Term
| What is stress relaxation? |
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Definition
| Slow decrease in force over time |
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Term
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Definition
| Increased stress around defects |
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