Dental Materials Chapters 43-46 Flashcards
What has to be done prior for dentin bonding to be successful
etching to remove the smear layer
etching a tooth is to remove
the smear layer - Thin layer of build up blocking tubules
bonding agents should be cured for
20-30 seconds
tooth whitening comes in what percentages
10,16,22
where do you place a dentin bond
on the dentin of a prepped tooth
Enamel bond can only be placed on what surface
intact enamel surfaces
What are 3 types of enamel bonds
sealants, ortho brackets, resin bonded bridges
Dental bonding reduces the ____ which reduces chance of ___
microscopic gap, microleakage
How does bonding improve retention
creates a Micromechanical retention between structure and restoration
3 precautions of using acid etch
it is corrosive, protect the pulp, avoid contact with soft tissue
What is the procedure for etch
- Dry cavity prep
- apply etch and leave for 15-30 seconds
- rinse and dry thoroughly
How does a successful etch make the tooth look
chalky or frosted
If saliva contaminates acid etch what do you have to do
repeat the process from step one
3 forms of acid etch
liquid/gel
maleic acid
phosphoric acid
How is amalgam placed in the tooth
placed in prep in small increments, condensed after each increment is added
why is amalgam condensed when placed
to tightly pack into the tooth, and to rise excess mercury to the top to be scraped off
for a small amalgam restoration a __mg capsule is used
600mg
for a large amalgam restoration a ___Mg capsule is used
800mg
What separates the powder and liquid components of a capsule
a thin membrane wall
What aids in mixing inside a capsule while in the trituration machine
a pestle
Trituration is
the process in which mercury and alloy powder is mixed to form amalgam
Trituration is AKA
amalgamation in an amalgamator
Scrap amalgam (non contact amalgam)
leftover pieces, capsules, etc
Trap amalgam (contact amalgam)
suction filter containing particles from mouth
How would you properly dispose of amalgam waste
in properly labelled wide mouth containers, with a tight sealing lid
Mercury Absorption is
absorbed directly through skin contact or inhalation of vapours
Two most common controversies of mercury
- Potential harm to patient
2. Toxicity level to DHCP
the amount of mercury released from pressure of chewing is
extremely small, you’re exposed to more in day to day life
What makes the mercury in amalgam restorations almost harmless
when its combined with the other materials the chemical nature changes
mercury is part of amalgam to make the mixture more ___
workable/pliable
Physical characteristics of mercury
liquid at room temp
vaporizes at high temp
gives plasticity
highly poisonous
what are the 4 metals found in alloy powder
silver, tin, copper, zinc
a 1:1 ratio of amalgam is the
Eames technique
What are the percentages of mercury to alloy
43-54% mercury, 57-46% alloy powder
Direct restorations are
applied/created directly in the mouth
what 5 materials are used for direct restorations
amalgam composite glass ionomers tooth whitening temporary restorative materials
Indirect restorations are
created in a lab, bonded or cemented in place
4 Materials for indirect restorations
nobel alloys, basic metals, ceramic, porcelain
what is an example of a indirect restoration
ceramic crown, PFM crown, FG bridge
Polymerization is
the process of resin changing from a pliable state to a hardened restoration
Hybrid (comp resin) is a
combination of large and small particle, strong and shiny
Microfilled
tiny and shiny, small particles (anterior teeth)
Macrofilled
strong and dull, large particles (posterior)
what 4 things is resin composed of
organic resin matrix
inorganic fillers
coupling agent
pigment
organic resin matrix is a
fluid monomer called dimethacrylate
BIS-GMA stands for
dimethacrylate
the coupling agent in composite resin is for
bonding filler to the resin matrix creating strength
3 examples of inorganic fillers
quartz, glass, silica
composite resin bonds to the natural structure, therefore it
moves fluidly with contact and expanding movements
there are how many classes of glass ionomers
6
what is the most versatile dental material
glass ionomer
2 advantages of glass ionomers
chemically binds to the surface
releases fluoride
Type I glass ionomer is for
cementation of indirect restorations
type II glas ionomer is
class V restorations near gingiva and root surface
type III glass ionomer is
Liners and bases
Sealants are a class ___ glass ionomer
IV
Ortho bands and brackets are a class __ glass ionomer
V
Type VI glass ionomer is for
core build up restorations
Glass ionomer is a ___ base
insulating
polycarboxylate is a _ and _ base
protective and insulating
A non irritating cement to the root would be
Polycarboxylate
can polycarboxylate be used under direct or indirect restorations
yes
Poly carboxylate bonds to
enamel
Zinc phosphate Type II (medium grain) is used for
insulating base of Deep cavity preps
Zinc phosphate type I (fine grain) is used on
permanent cementation of indirect restorations
Castings / cast restorations are AKA
indirect restorations
zinc phosphate is ___ to the pulp
irritating
what would you use before a zinc phosphate cement to protect the pulp
a liner or desensitizer to counteract the acidity
what should the temp of a glass slab be while mixing zinc phosphate
68 degrees F
what is the cool glass slab intended to do while mixing
dissipate the heat and increase working time
when mixing zinc phosphate the powder must be added to the liquid in
small increments
ZOE type III (IRM) is used for
placement of Temporary restorations (primary teeth, emergencies, regenerative)
ZOE cavity liner is class
IV
ZOE type II is for
permanent cast restorations or appliances
why is ZOE type II stonger than type I
it has added reinforcements to create strength to hold a permanent
ZOE type I (temp bond) is for
temporary cementation/provisional coverage
ZOE stands for
zinc oxide eugenol
IRM stands for
intermediate restorative material
eugenol is oil from
cloves that have a soothing/sedative effect on the pulp
what is the fulcrum
finger rest
what tools are used in the removal of cement
explorer, mirror, scaler, floss
Variable that effect cementation are
temp, humidity, mixing time, liquid/powder ratio
Permanent Luting agents are used for
long term cast restorations
long term cast restorations (indirect) are
crowns, bridges, veneers, inlays, onlays, fixed ortho appliances
when seating crowns, luting agent must be evenly filled and equally __
distributed
Temporary luting agents are used for
when a restoration needs to be removed later on (intermediate)
What would you use a temp luting agent on
a temporary crown, bridge, veneer
what is the consistency of a temporary luting agent
thick putty like, tacky and able to be rolled into a ball
luting cement has a consistency of
syrup, should create a string when lifted
luting agents act as a
glue holding tooth structure and casting together
Dental cements come in forms of
luting agents, liners & bases, IRM
Sedative bases
soothe damaged or irritated pulp
Zinc oxide eugenol is a ___ base
sedative
Insulating bases are
placed in deep preps to protect from thermal shock
zinc phosphate, polycarboxylate and glass ionomer are all ___ bases
insulating
Protective bases
reduce post op sensitivity and damage to pulp
Which base is protective and insulating
polycarboxylate
dental bases are applied after liner to provide
pulpal protection from acidic cements
when applying desensitizer you use a
cotton tip applicator and apply on exposed dentin
What can you use in place of a varnish that does not need any prep
desensitizer (primer)
desensitizer is used to seal tubules from
oral fluid getting between tooth and restoration
HEMA and glutaraldehyde are found in
desensitizers
HEMA stands for
hydroxethyl methacrylate
Cavity varnish can only be used under which material
amalgam
cavity varnish interferes with bonding and setting reactions of which materials
composite resin and glass ionomers
cavity varnish is used to
seal dentin tubules, reduce micro leakage, and a barrier from highly acidic materials
Calcium hydroxide is known as
dycal
calcium hydroxide is used to
protect pulp from chemical irritation
when would you use dycal
when pulp exposure is expected or seen (red spots)
Cavity liners are used to line the
deepest portion of the prep and seal tubules
cavity liners regenerate the production for
dentin
Physical pulpal responses are
thermal and electrical
mechanical pulpal responses are from
handpiece vibration and improper occlusion
chemical pulpal responses are from
acids in dental materials
biological pulpal responses are from
bacteria in saliva contaminating the exposed pulp
vibration from a handpiece on an irritated tooth can cause a
mechanical pulpal response
what dictates the dental liner/base to be used
depth of prep
what is utility wax used for
extending the length and height of an impression tray
bite registration wax is used to
take a bite impression
inlay casting wax is to form patterns of
indirect restorations on model
casting wax is used for
single tooth direct restorations
when trimming models you should always
wear goggles/mask
soak in water for 5 minutes prior to trim
start trimming biggest arch and then match
use proper angles on art portion
which impression model material uses the most water
plaster
Anatomic portion
teeth of model
art portion
base of model
3 types of gypsum products
stone, high strength stone, plaster
high strength stone is AKA
densite or improved dental stone
3 types of Occlusal impressions
ZOE bite registration paste
wax bite
polysixoline bite registration paste
Hydrophobic
impressions that dislike moisture
syneresis
alginate impression looses moisture and shrinks
imbibtion
alginate impression absorbs water and expands
smearing
additional alginate in undercuts, occlusal, inter proximal, palate
glazing
smoothing surface of alginate by wiping moist finger across surface
2 types of alginate impression material
fast and normal set
maxillary alginate has
more powder and water
alginate is a
irreversible hydrocolloid
alginate beading is the use of __ to extend tray
utility wax
2 types of impression trays
stock and custom
final impressions are taken to make
indirect restorations, dentures, implants
preliminary impressions are used for
custom trays, diagnostics, provisional coverage
Impressions are the ___
negative
gypsum products are used to make the ___
positive
3 types of curing
auto cured, light cured, dual cured
Retention
the ability to hold two things firmly together when they don’t naturally adhere
why are retention cuts used in amalgam
it docent naturally adhere, cuts add more stability
wetting
ability of liquid to flow over a surface into irregularities
viscosity
property of a liquid not able to flow easily
surface characteristics
a liquid flows easier on a rough surface than smooth
film thickness
thinner the film better the adhesion
adhesion
how well a product sticks
flow
how a product moves within a tooth when placed
solubility
substance dissolving in another
corrosive factors
temp, humidity, saline, foods
4 application properties
adhesion, flow, retention, curing
2 corrosive properties
solubility, corrosive factors
galvanic action
electric shock
what causes electrical shock
interaction of multiple metals in the mouth
thermal change
rapid temp change causing contraction and expansion
ductility
metal stretched by tensile force without fracture
malleability
metal extended in all directions without fracture
shear stress (grinding) is
two forces parallel sliding in opposite directions
compressive stress (chewing) is
two forces pushing towards eachother
tensile stress (tog of war) is
two forces pulling away from eachother
mechanical forces are
biting forces and stress & strain
