Term
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Definition
| An internal resistance to an externally applied force |
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Term
| What is stess measured in? |
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Definition
- Pascals
- PSI
- meganewtons per square meter
- megapascals
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Term
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Definition
- Forces on an object that are directed toward one another
- malleability
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Term
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Definition
- Forces on an object are directed away from one another
- ductility
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Term
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Definition
- Forces on an obect are directed in such a manner to twist, rotate, or deform the object sliding one part parallel to the other
- harmful to human dentition
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Term
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Definition
| change in length of the sample as a result of an applied force |
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Term
| What is strain measured in? |
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Definition
- unitless
- percentage of change (ΔL/L x 100)
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Term
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Definition
| Stress/strain until no longer proportional; also measures material's stiffness |
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Term
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Definition
- strees proportional to the strain
- past this point the object no longer retains original shape
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Term
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Definition
| Strain associated with stress at proportional limit |
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Term
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Definition
| small but permanent dimensional change |
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Term
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Definition
| repeated application of stress |
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Term
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Definition
| ability of a material to withstand permanent deformation under tensile stress w/o fracture |
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Term
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Definition
| Abilit of a material to withstand permanent deformation under compressive stress w/o fracture |
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Term
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Definition
| amount of deformation a material can withstand w/o rupture when a TENSILE stress is applied |
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Term
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Definition
| the amt of deformation a material can withstand w/o rupture when a compressive stress is applied |
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Term
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Definition
- The heat (in calories or joules) required to convert 1g of a material from solid to liquid at the melting temp.
- L=Q/m
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Term
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Definition
| the amt of heat per second passing through a body 1-cm thick with a cross section of 1 cm2 when the temp difference is 1 Celsius degree |
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Term
| Why is it important to know thermal conductivity? |
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Definition
| b/c metallic restorations in close proximity to the pulp may cause patient discomfort when hot or cold foods come in contact |
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Term
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Definition
| the amt of heat needed to raise the temp of 1g of the substance 1 Celcius degree |
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Term
| What has a higher specific heat liquid or solid? |
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Definition
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Term
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Definition
| rate at which a body w/ a nonuniform temp approaches equilibrium |
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Term
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Definition
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Term
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Definition
- lightness of color
- 1= black, 10= white
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Term
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Definition
- intensity of color
- 1= unsaturated, 10= saturated
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Term
| What is the Hue, Value, and Chroma for a natural tooth? |
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Definition
- Hue: Yellow
- Value: 6-8
- Chroma: 1-3
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Term
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Definition
| Colors under a fluorescent light source differ under a natural light source |
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Term
| What elements fall under face-centered lattice? |
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Definition
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Term
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Definition
| permanent deformation under load in CRYSTALLINE materials |
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Term
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Definition
| permanent deformation under constant load in AMORPHOUS materials |
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Term
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Definition
| Energy required to deform a material permanently; area beneath the linear portion of stress strain curve |
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Term
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Definition
| Energy necessary to fracture a material; total area beneath stress-strain curve |
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Term
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Definition
| Materials resistace to indentation |
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Term
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Definition
| bonding between UNLIKE materials |
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Term
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Definition
| material used as a binding agent |
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Term
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Definition
| the surface to which adhesive is applied |
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Term
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Definition
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Term
high contact angle (greater than 90 degrees)
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Definition
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Term
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Definition
small electric currents created when two dissimilar metals are present in the mouth
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Term
| Electrochemical corrosion |
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Definition
| combination of chemical reaction and flow of electric current; oxidation (loss of electrons at surface) of metals |
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Term
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Definition
| variation in composition of metals on a single surface; eutectic alloys in combination with other alloys |
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Term
| Nonuniform surface corrosion |
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Definition
| occurs when final finishing of metal creates surface stress causing a battery (corrosion) to form between the stressed metal and the saliva |
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Term
| Concentration cell corrosion |
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Definition
| metals exposed to two solutions, or electrolytes, at the same time |
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Term
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Definition
| study of the flow of liquids |
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Term
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Definition
| Calcium Sulfate-dihydrate |
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Term
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Definition
| gypsum ground and heated until H20 is removed |
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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
| are so constructed that neither the fuel nor the fire gases come in direct contact with the material to be calcined. A retort (A) of iron, brickwork, or fire-clay, is placed over the fire grate (G). Flues (F. F) are built around the retort, and through these the hot gases from the fire pass on their way to the chimney (E). |
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Term
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Definition
are built in many forms, but in all cases the flames and hot gases from the fire come in direct contact with
the material to be calcined, but the fuel is separated from it. |
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Term
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Definition
- impression plaster
- requires different fillers and retarders, used exclusively on the completely endentulous patient with no undercut areas
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Term
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Definition
- Model plaster
- Plaster of paris
- is primarily used for orthodontics or low strength model pours
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Term
| Dental plaster: Types I and II |
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Definition
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Term
| Dentals Stone: Type III, IV, V |
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Definition
- Type III - model stone
- Type IV - die stone
- Type V - high strength
- alpha hemihydrate
- requires less water
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Term
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Definition
| all gypsum products expand during setting; setting expansion normally is 0.1 to 0.2 percent |
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