Physical properties - Dental materials

Time dependent plastic strain of a material under a static load or constant stress

• Flow

• Creep

• Velocity

• Stress

Eye is sensitive to -λ of 400nm(violet)- 700nm(red).

• True

• False

Eye is most sensitive to light in green-yellow region(550nm)

• True

• False

Exceptionally sensitive scientific instrument that measures intensity and wave length of light

• Spectrophotometer

• Calorimeter

• UTM

• All

Change in length per unit length of a material when its temperature is raised 1˚k. (μm/m˚k)

• Coefficient of thermal expansion

• Coefficient of thermal conductivity

• both

• none

Certain metals develop a thin ,adherent, highly protective film by reaction with environment

• Corrosion

• Passivation

• Erosion

Corrosion resistance is very important consideration dental alloys because release corrosion products affect

• Physical property

• Chemical property

• Biocompatibility

An important type of E-C corrosion occurring when combinations of

• Similar metals

• Dissimilar metals

• Alloys

• Molecules

Disintegration of a metal by corrosion may occur in mouth because of

• warmness and moistness

• fluctuations in temperature

• ingested foods with wide range of PH

• acids liberated from localized attachment of debris

• all the above

The process by which a metal surface is dulled or discolored when a reaction with a sulfide ,oxide, chloride, or other chemical causes a thin film to form

• Tarnish

• Corrosion

• Erosion

• Moisture