Test #1- 1 Flashcards
What are qualities of metal
-high thermal electrical conductivity
-ductility
-opacity
-luster
*atoms in regular or crystalline arrangement
high atomic bond strength
What are qualities of a crystalline arrangement
liquid to solid
3 spatial dimensions
What are qualities of Ceramics/Porcelain
very brittle, high melting point, low thermal and electrical conductivity, not very chemically active
What are ceramics/porcelain a combination of
kaolin, feldspar, quartz
Molded without chemical reaction taking place; change takes place with temperature changes
thermoplastic- dental polymers
a chemical change that takes place during molding
thermosetting
a small organic molecule that can be bound to similar molecules to form a polymer
monomer
material composed of many repeating units called monomers
polymer
plastics are
synthetic
rubber is
natural
polymerization is
the conversion of low molecular weight compounds (monomers) to high molecular weight compounds (polymers)
what contains 2 or more different monomers
copolymer
what is a cross-linking agent
network of adjacent polymer chains, makes polymer stronger
what is a composite
*dimethacrylic acid polymer
What material is heavily filled and used for direct restorations, veneers, inlays cementation, and sealants
composite
more fillers =?
increased strength
what is the galvanic response
coupling of 2 dissimilar metals
what is thermal conductivity
rate at which heat flows through a material
what is solubility
ability to dissolve in liquid
what is the liquid a substance dissolves in
solvent*
what is the uptake of fluids into a solid
sorbtion/absorbtion
when is sorbtion detrimental
when restorations or cement deteriorate
What is the primary result of molecular interaction
result of from chemical bond
what are primary molecular interactions based on
polyacrylic acid
what is the secondary molecular interaction
physical forces with no chemical union
*most common
*what is the wetting angle
angle measured through the liquid at which a liquid interface meets a solid surface
(how well a liquid covers the surface of a solid)
what does it mean when there is a high contact angle
less of the surface is covered, hydrophobic, less wetting
what contact angle does a good adhesive have
one that approaches zero
low contact angle=
hydrophilic, more wetting
what are some examples of material with a lower wetting angle
- impressions
- bonding agent
what is disintegration
- breaking up of a solid
- end process of fluid and material interactions
what is adhesion
attaching two solids together
what is the force of attraction between molecules or atoms on two different surfaces
adhesion
What are tensile forces on an object
forces are directed away from each other (stretched or elongated)
What is the ability of a material to resist pulling
tensile strength
what is the resistance in the material to the external force or ability to resist pushing
compressive
what is shear
ability to resist tearing forces directed parallel to eachother
what force is when one portion of a structure is forced to slid by another portion
shear
was the is the elastic limit
- measures the stiffness of a material
- maximum stress with out permanent deformation
what is AKA a proportional limit
elastic limit
compression=
denting
tension=
stretching
shearing=
bending
Torsion=
twisting
What is ultimate strength
point just before fractures
what is ductility
ability to be drawn into a wire
ductility=
low ductility=
elongation
brittleness
malleability
ability to be hammered or rolled into thin sheets without fracture (compression)
Resilience
energy necessary to cause permanent deformation
toughness
ability of material to resist fracture
creep
gradual permanent change in dimension that occurs in an object due to constant loading, (flow after set, amalgam)
viscosity
ability of a material to flow
thixotropic
some materials have high viscosity but change with pressure (mixing, impression material)
What is Rockwell hardness (RHN)
depth of an indentation made with a steel ball, composites
what is knop harness (KHN)
measuring the length of a diagonal made with a diamond indenter (metals and porcelain)
Fatigue is created by
repeated application of stress to an object causing tiny cracks to be generated within the structure until failure occurs
*stress =
force applied to specific area
What are mouthguards made of
semirigid but soft plastics (resins)
these are made of thin sheets of material that are thermoplastic (soft molded) then becomes rigid and holds shape
mouthguard
what are splints used for
to distribute biting or grinding forces to prevent injury to teeth, alveolar bone or TMJ
what is a periodontal splint
used to transfer forces to adjacent teeth allowing compromised tooth support
what are perio splints made of
wire, mesh, metal or plastic
do applicable self test and crosswords about bleaching to prep for exam
-
what is designed to be placed on a tooth for a limited time to maintain integrity and function of dentition
temporary restoration
what materials are used for temp restoration
acrylic, composite, synthetic resins, ZOE
What do we have to be careful with, with acrylic resin temp restorations
they are exothermic and could damage pulp and surrounding tissue
what are examples of synthetic resins
acrylic, polymers, plastics
in acrylic resins what is added to the heat monomer and polymerization initiator to create a resin
methacrylic acid
what are some examples of acrylic resins
sealants, direct restorations, inlays, denture teeth, denture base and saddle, ortho appliances
what is a resin
a class of solid or soft organic compounds of natural or synthetic origin, high molecular weight most are polymers
what are examples of resins
polyvinyl, polyethylene, polystyrene
what is a synthetic
made my chemical synthesis, combining elements into a whole
what does ZOE consist of
zinc oxide particles, additives, eugenol
__________ is acidic and can irritate pulp, but also stimulates secondary dentin which insulates pulp
Eugenol
ZOE cant be used under what*
composite materials, inhibits polymerization
what as been used as a liner under amalgam restoration
ZOE
what is added to ZOE to increase strength
acrylic fillers
ZOE qualities:
soluble in oral fluids
poor compressive strength
porous
what does the sedative effect of ZOE determine
if a tooth is likely to respond well to permanent restorative efforts
