Dental Materials Flashcards
chemical attraction between unlike molecules
adhesion
chemical attraction between like molecules
cohesion
n index which indicates how one material reacts to temp extremes in relation to another
coefficient of thermal expansion
the force at which a material breaks under pressure
compressive strength
slow dimensional change caused by compression
creep
the ability to undergo change of form without breaking
ductility
a material’s ability to recover its initial shape after undergoing a force
elasticity
an electrical current generated by dissimilar metals in an acidic environment
Galvanism
the process of solidification by cold (gelling)
gelation
absorption of a solvent by a gel
imbibition
a material’s capacity to be shaped by force or pressure
malleability
passage of oral fluids/bacteria into and out of tooth structure due to a marginal gap or failure of the marginal (restorative) seal
micro leakage (percolation)
the linking, branching, or cross linking of smaller molecules to generate a larger molecule
polymerization
the force at which a material can not return to its original shape
proportional limit
the force needed to stretch a material to the point of fracture
tensile strength
resistance to flow
viscosity
an alloy of mercury with silver, copper, tin, and zinc
amalgam
why is copper added to amalgam
minimize corrosion- gamma II phase eliminated
is silver (a base metal) susceptible to corrosion
yes
desirable features of what? - *durable, compressive strength similar to enamel, relatively inexpensive
amalgam
undesirable features of amalgam
unattractive, high thermal conductivity, dimensionally unstable (creep), delayed expansion if contaminated by saliva, requires tooth support, fracturable by excessive occlusion, susceptible to galvanism when new
final polish in mouth of amalgam is with what
tin oxide
establish micro mechanical retention with enable and dentin by adapting to relief areas created by conditioning with phosphoric acid
dental resins (BIS-GMA or urethane dimethacrylate)
bonding failures usually do to what in sealants
contamination by saliva or oils
if contamination occurs during sealant placement what do you do
re etch
most common filler particles in composite
silicates, quartz, glass
used to seal dentin or medicate the dental pulp (seal/medicate)
liners
liner. soothes the pulp*, oily, contra indicated with composite
zinc oxide/eugenol
used to provide thermal insulation or mechanical protection for the dental pulp. includes all cements
bases
used to affix a restoration to tooth structure, or as a base
cements
commonly used for *temporary cementation, orange solvent used to clean this off
zinc-oxide/eugenol cement
reversible hydrocolloid, physical reaction, temperature dependent, susceptible to imbibition and synopsis, gelation, hydrophilic, flexible
agar
irreversible hydrocolloid, chemical reaction, not temperature dependent, susceptible to imbibition and synopsis, hydrophilic, flexible
alginate
you need to do this to prevent setting/compaction of powder for alginate
aerate (fluff)
this is a mineral, calcium sulfate di-hydrate
gypsum
the ____ water needed, the greater the setting expansion (dimensional change) and lower the compressive strength of the final product
more
beta calcium sulfate hemi hydrate
plaster, type II gympsum
alpha calcium sulfate hemi hydrate, better than beta
stone, type III gypsum
alpha calcium sulfate hemi hydrate, with additive to make more durable and wear resistant
diestone, type IV gypsum, also called improved stone
what to do to accelerate set of gypsum
add potassium sulfate, mix with warm water
what to do to slow set of gypsum
borax
wax, used to modify the shape of impression trays and cushion braces
utility wax
wax used for cast restorative patterns
inlay and casting wax
wax useful to obtain occlusal records
bite registration wax
wax useful in removable prosthetic procedures
baseplate wax
wax used in pouring models (vertical wax around impression)
boxing wax
wax that becomes sticky when heated, used to attach models
sticky wax
used to fabricate inlays, onlays, crowns, and bridges
casting alloys
resist tarnish and corrosion
noble metals
noble metals include
gold, platinum, palladium
subject to tarnish and corrosion, may be allergenic
base metals
base metals include
silver, copper, nickel, tin, and zinc
implants are _____ (within bone)
endosteal
leading cause of dentinal sensitivity
pyrophosphate - tartar control toothpaste
