dimensional change
a change in the size of matter for dental materials that usually manifest as expansion caused by heating and contraction by cooling
reason why dental material may change size
setting process, exposure to heat and cold associated with
percolation
Passage of a liquid to flow slowly between gaps in teeth.
soulbility
how easy a substance can be desolved
sorption
process in which one substance takes up or holds another by either absoprtion or adsorption
absorption
uptake or accumulation
adsorption
The accumulation of gases, liquids, or solutes on the surface of a solid or liquid.
flow and creep
deformation of a solid when subjected to constant stress.
three types of stress
Compression, Tension, and Shearing
strain
change in length or deformation produced by stess
elastic strain
deformation that is not permanent, provided the stress is released
plastic strain
permanent deformation has occurred; upon removal of force, body does not return to original dimensions
proportional limit
The maximum stretch or load that will cause no permanent deformation.
yield strength
The point at which the material stops being elastic and starts being plastic.
ultimate strength
The load required to cause actual breakage.
elastic modulus
Relative stiffness of a material; ratio of elastic stress to elastic strain
elongation
amount of deformation before material ruptures under tension (tensile stress)
malleable
ability of a material to withstand permanent deformation under compressive forces
hardness
resistance of material to indentation under compressive forces without penetration
four hardness test
brinelle, rockwell, vickers knoop (bill rocked vickies knickers)
wettability
measurement of liquid wetting a solid
viscosity
way material flows
low viscosity
Flows easily
high viscosity
Flows slowly
thermal conductivity
how material conducts temperature
adhesion
an attraction between molecules of different substances
galvanism
an electrical current transmitted between two dissimilar metals
corrosion
dissolving of metal in mouth. wears away need to replace
tarnish
suface discoloration. Reaction of metal to saliva or food.