damage pulp

pain on restoration if close to pulp

protect against temp and electrical charges

only a small amount is needed so it doesnt crack from pressure exerted from chewing/biting

true/false 

all dental materials have some solubility in water?

absorption of fluid

usually affects poymeric materials and also porcelain

increases likelihood that resorption will be retained on the teeth.

excessive removal of teeth is lessened

promotes the sealing of margin

high viscosity whould have high resistance and would not spread easily?

true/false

true

and example is honey it is thick, spreads slowly, highly viscous, and high resistance

an object or modifier

a light source

someone with the capacity to observe or recieve the modified light coming from the object.

munsell:  visual systems

CIE- a spectrophotometric system (measures red, blue, and yellow)

hue

value

chroma

dominant color of object

ie teeth are usually yellow to yellow-red

value of color

normal value is 6-8

saturation or the intesity of the color 1-10

(if 10 it is fully saturated)

usually normal teeth are low in saturation 1-3

the fact that light entering the tooth may be affected in several ways

light may be transmitted through

may be reflected

may be scattered

may be transparent

chromium 

it protects agains corrosion

chlorine is bad for chromium 

when two dissimilar metals touch each other ie aluminum foil and amalgam or amalgam and gold

they create an electrical current

it can produce metal oxides and fall into crevices to help seal out bacteria

it can also increase longevity of restoration by reducing potential for secondary / recurrent decay

fluid gets in and out of interface between restoration and tooth

could result in corrosion or decay

combo of tensile and compressive

ie a bridge that spans a long length will have this

slide to top of an object over the bottom

ie a deck of cards spread out on a table

force/area

change of dimension

deformation/length 

when stress is applied and snaps back into position and has elasticity.  the dimension was recovered.

the elastic modulus or also called youngs modulus

most stress that can be absorbed without permanent deformation

aka proportional limit or yield point

where it does not snap back into its origional dimension

compression- squeezing stress

tension-pulling stress

shear-sliding stress

torsion-twisting stress

bending-combo of compression and tension

resists indentation

resistant to wear and abrasion

helpful in knowing what can withstand biting force

gradual but permanent change in dimension that occurs in an object subjected to a constant load.

example poissons ratio and dental amalgam  (biting too hard makes changes)

slow decrease in force over time

ie,  ortho rubber bands lose force over time and must be changed

loads applied will cause change in 3 dimension

stress will be higher around defects

fractures could occur

intrinsic factor that describes ability to resist fracture or crack

high fracture toughness indicates good resistance to cracking

 when 2 surfaces are brought into direct contact with a third body acting between them.

ie, sandpaper removing material from wood

tries to lay down more dentin

odontoblasts transmit message to pulp

pain messages can be transmitted by hydrodynamic theory

cooled materials will contract and heated materials will expand. a measure of this change in temp is called the coefficient of thermal expansion.

true/false