Quiz #2 Dent Mat Flashcards
3 oral environment factors to take into consideration
temp changes
corrosive environment
mechanical stresses
what are 3 types of primary bonds
ionic
covalent
metallic
what is a type of secondary bond
van der waal forces
what is found in van der waal forces
H bonds
which primary bond is the strongest
covalent
what do many ceramic dental materials consist of
ionic bonds
what do polymeric materials consist of
covalent bonds
what is a metallic bond
atoms are held together by interactions of valence electrons. however, the e are free to move throughout the solid bc the valence electrons are not bound b/w metal ions
energy is transferred easily through what types of bonds
metallic bonds -> good metal conductivity
can a material have 2 types of PRIMARY bonds?
yes
how is the h bond created
by a permanent dipole that exists within asymmetric molecules
what is an arrangement of atoms
crystalline structure
what is a crystalline structure
a repeated consistent internal structure
4 types of crystalline solids
all metals
non-glassy ceramics
polymer fibers
tooth enamel
a repeated consistent internal structure is known as a
crystalline structure
what is stress
forces within the structure that cause strain
what is strain
the deformation in the structure
what is surface tension
caused by the attractive forces b/w molecules of a liquid.
what is a good wetting property?
small contact angle -> promotes capillary penetration
2 mechs of adhesion
chemical and mechanical
what does adhesion occur through
primary or secondary bonds to the substrate
chemical adhesions is used to bond to
dentin
many cements bond to
the calcium of hydroxyapatite
what is ADsorption
process where a liquid or gas adheres to a SURFACE
what is ABsorption
process where a liquid or gas PENETRATES into solid material
3 mechanical forces in the jaw
torsion, compression, shear
stress is always a combo of
tensile, compressive and shear stresses
what is Poisson’s ratio
measure of lateral strain relative to axial strain
would you want to use a ductile or brittle material
ductile
what is resilience
amount of elastic energy a material can absorb.
area of energy UNDER the linear portion of the stress-strain diagram
what is toughness
area under the entire stress-strain curve. represents the amt of energy the material can absorb before failure
low VP causes faster/slower evaporation
SLOWER
creep
is a slow deformation of a viscoelastic material over time
CREEPS UP
stress
force per unit area
ultimate strength
max stress the material withstands
yield
point at which plastic strain begins
plastic strain
permanent deformation
shear strain
caused by shear stress
