DMS Flashcards
DMS Meanings:
- soldering
- wrought alloy
- example
- quenching
4 . allotropic - tempering
- milled
- melting a metal to join two dif. metals together
- alloy that has been work hardened
- stainless steel ortho wire
- rapid cooling to adjust metals properties
- element that exists in two or more forms (i.e. diamond and graphite)
- metal heated bellow MP and cooled in air to increase toughness
- cut metal into shape
definition of an alloy
- types of alloy
Stainless steel:
- constituent elements and their functions
General understanding of the types of iron and how they are formed, including the formation of the type required in stainless steel
work hardening
- what
- what it causes / its benefit
- what required to be done to relive stress built up in this process
- Heating metal/or not (but bellow re-crystallisation temp) and shaping it in some way (hammering, rolling, drawing) - causing plastic deformation = increased hardness
- causes cold working
- SLIP = dislocations form at grain boundaries = less in lattice = harder and stronger
- plastic deformation - benefit = dislocations prevent layers from sliding past each other as easily = stronger
- annealing
- heating metal 450 degree (always bellow MP) and cooling very slowly and specifically to reduces stresses in metal
denture base maid of stainless steel
- how
- positives and negatives
- swagging = die and counter-die with shape press on stainless steel to force it into a shape
- bad = many ways in which shape not good (elastic recovery inaccurate, die and hydraulic press issues, not guaranteed uni-thickness)
- good = thin, high thermal conductivity, corrosion resistant, light, etc
ideal properties for denture base (11)
Denture bases: PMMA
- types
- reaction to cure? and stages of this reaction? (4)
- heat cured / self cured
- image
PMMA denture bases
- PMMA meaning
- polymethyl methacrylate
heat cured acrylic PMMA
- composition
- process for making
- properties (good bad and in-between)
which PMMA denture material is preferred for ortho and why THIS IS WRONGGG
self cure, although neither perfect
as less thermal contraction and only water absorption so slightly larger = better tolerated than the slightly shrunk heat cured
WRONGGG
Self cured PMMA denture base
- composition
- properties (good and bad)
alternative denture base materials (5)
Endo DMS files definitions of relevant meanings
stress
stress concentration
strain
elastic limit
elastic deformation
plastic deformation
plastic limit
shape memory
2 types of fatigue that lead to failure of endodontic files? and what they are?
prevention methods for breaking? (6)
two methods of manufacturing for endo files
two materials used for endo files
endo irrigation DMS:
function
what is the smear layer and why needs removed
types (5)
effect of sodium hypochlorite, EDTA and citric acid and % needed for irrigation pre root filling
sodium hypochlorite
= antimicrobial
= 3%
EDTA / citric acid
= removes smear layer
= 17% / 10% (for citric)
DMS: obturation materials
what and two types
composition
desired properties
DMS endo sealers
function
desired properties
example materials (5)
DMS: endo:
MTA (stands for?)
function
characteristics
two types
elastomeric impression materials
3 types
- polyether
- addition silicones
- alginate
elastomers formation that gives elastic characteristic
Polymerisation with cross linking of polymer chains
factors influencing reproducibility of impression materials by their quality of interaction with the hard and soft tissues? (3 - 5)
DMS: impression materials:
polyethers vs addition silicones comparison in:
setting time
working time
elastic recovery time
shark fin test
resisting tear on removal
DMS: how to adequately make a decision on a dental material bases on manufacturers information:
PMMA as a temporary material
positive and negatives
4 temporary materials
research into the exothermic reactions of restorative materials and what they found?
investment materials:
what for
examples (4)
- and what each used for
desired characteristics
two component parts of material
investment material technique used to make alloy shaped:
and its stages
investment materials: Gypsum bonded materials:
composition
dimensional changes (3)
properties
used for
used for gold casting alloys
investment materials: Phosphate bounded materials:
composition
properties
used for
used for: base metals / cast ceramics
investment materials: silica bounded materials:
properties
luting agent examples (4)
ideal properties of luting agents
Dental cement: zinc phosphate cement:
reaction
setting
positives/negatives
Dental cement: zinc polcarboxylate cement:
reaction
setting
positives/negatives
Dental cement: zinc polcarboxylate cement:
reaction
positives/negatives
Dental cement: glass ionomer cement as a luting agent:
what
setting
positives/negatives
Dental cement: resin modified glass ionomer cement as a luting agent:
what
reaction
importance of resin qualities added to GI
problems
composite luting agents
benefits/negatives
how bond to:
- composite
- porcelain
- metal
- precious metals
what are the two composite luting agents adapted for specifically luting
Temporary luting cements
what
how mixed?
two types
which luting agent best used for different types of materials if
A. easy
B. complicated
Porcelain
positives/negatives
properties
5 required characteristics of an alloy to be compatible with porcelain
5 required characteristics of an alloy to be compatible with porcelain
porcelain fused alloys:
why
how
alloys compatible with porcelain
which most common*
- cobalt chromium***
- silver palladium*
- low gold alloy*
- nickle chromium
- high gold alloy
- MP too low = creep AND not sufficiently rigid (too <Young’s modulus)
- composition - more gold, less everything else (compared to low gold alloy)
where are most failures of porcelain-alloy structures
within the porcelain itself
what are the 3 techniques used for making porcelain crowns?
what are the 4 main materials used?
- conventional feldspathic porcelain painted and furnaced
- pressed crowns
- milled /monolithic crowns
- zirconia core
- lithium disillicate core
- metal cores
- conventional feldspathic porcelain with no core
decorative vs dental ceramics differences? (5)
main difference and its function
how is colour changed?
conventional ceramics
what
how produced
how used
conventional feldspathic ceramics:
positives
negatives
how overcome these problems?
what is the conventional ceramics technique
and what are the new techniques? (4)
conventional feldspathic ceramics
- potassium alumina silicate
- zirconia
- lithium silicate
- pressed crowns
- monolithic / milled crowns
zirconia core ceramics
what
how made
composition important factor
process of making into core
positives / negatives
milled / monolithic crowns and bridges
materials milled
how done
most important property of of milled crowns
cast / pressed ceramics
technique used (process)?
comparison of different crown materials and techniques compared
sintered vs milled vs pressed crowns
where and when use what technique and material for crowns in the mouth
posterior teeth
anterior teeth
anterior bridge work
longer span or heavier occlusion
luting differences between zirconia and lithium disilicate bases
what are and different types of indirect restorations
Inlay restoration
what
material types
uses
indications
adv / disadv
preparation
process
cementation
Onlay restoration
what
types
indications
preparation
process
cementation
Veneer restoration
what
types
indications
contraindications
process
preparations
adhesion
alternatives
what are the 4 main features of materials (8 opposite properties)
what does a high Young’s/elastic modulus mean
the materials is very rigid
what does a stress strain curve graph show (7)
what is strong coping in the chemistry of porcelain
alumina added to porcelain, particles sit within porcelain structure to prevent the progression of cracks becoming larger as interrupts them
increases flexability of material
Bonding of onlays and crowns with what (David’s page)
