density
measure of the weight a material has compared with its volume (marshmallow)
hardness
the resistance of a solid to penetration, also resistance to wear and abrasion
ultimate strength
the maximum amount of stress a material can withstand without breaking
elasticity
ability of a material to recover its shape completely after deformation from an applied force (rubber band)
stiffness
materials resistance to deformation, measured by young's elastic modulus-stiffer materials have higher modulus. The greatest stress a material can withstand without permanent deformation is the proportional limit
resilience
is the resistance of a material to permanent deformation
toughness
the ability of a material to resist fracture
ductility
the amount of dimensional change an object can withstand without breaking
malleability
the ability to be compressed and formed into a thin sheet without breaking
thixotropic materials
are materials that flow more easily under mechanical forces (toothpaste, ketchup)
viscosity
the ability of a liquid material to flow
dimensional change
all forms of matter expand when they are heated and contract when cooled
coefficient of thermal expansion
measurement of the change in volume or length in relationship to change in temperature
percolation
repeated shrinkage and expansion of a restoration during ingestion of cold and hot fluids and foods producing an opening and closing of a gap between the restoration and the tooth surface
thermal conductivity
the rate at which heat flows through material (metals are good at this)
heat capacity
amount of heat a material can retain/hold/hoard
heat of fusion/vaporization
how much energy is required to melt, boil or vaporize
water sorption
ability to absorb moisture
corrosion
deterioration of metals due to a chemical attack or electrochemical reaction with a dissimilar metal
tarnish
when the surface of a metal restoration, especially amalgams, can undergo discoloration due to oxidation of the surface of the metal
galvanism
transmission of electrical current between two dissimilar metals
wetting
the degree to which a liquid adhesive is able to spread over the surface of the tooth and restorative material
film thickness
the minimum thickness obtainable by a layer of a material (dental cements)
surface characteristic
cleanliness of the surface, moisture contamination, surface texture and surface energy of the restoration and tooth
hue
is the dominant color of the wavelength detected (teeth are seen in the yellow and brown range)
chroma
is the intensity or strength of the color (teeth are rather pale in color)
value
describes how light (white) or dark (black) the color is (teeth have value ranges in the light scale)
transparent
light passes directly through an object
opaque
light is completely absorbed by the object
translucency
the quality of partially transmitting and partially scattering light
hardness
ability of a material to resist forces of indentation
fatigue
repeated application of stress to an object causes tiny cracks to be generated within its structure
creep
the gradual but permanent change in dimension that occurs in an object subjected to a constant load
wear
complex phenomenon that occurs when two surfaces are brought into direct contact of indirect contact with a third body acting between them (most common types are abrasion and attrition)
compressive force
force applied to compress an object, pushing or crushing stress, biting down on something
tensile force
force applied in opposite directions to stretch an object, pulling stress
shearing force
force applied when two surfaces slide against each other,sliding stress
force
is a weight or load that is applied to an object
stress
resists the applied force
bending
combination of stresses/compression and stretching plus compressive, shearing and tension within an object
elastic limit
maximum stress level at which complete recovery of strain occurs on release of the stress
elastic deformation
the object returns to its original shape after stress is removed
plastic deformation
point where stress is no longer proportional to strain, the object will not return to its original shape
ultimate strength
the maximum stress that can be withstood before breaking
stress
force or load applied to an object
strength
resistance internally to the stress
strain
internal rearrangement of atoms to adjust stress (change is length divided by original length)
relaxation
attempt of material to return to its original form
deformation
change in shape from the strain