DMS Flashcards
what are the differences in composition between decorative and dental ceramic
dec has koalin 50% but den has less that 5%
dec has 15% feldspar but den has 70-80%
dec has 0% glass but den has up to 15%
transluceny
allows transmission of light, but not completely transparent
opalescence
material appears to change in colour when viewed under different lighting
colour shift, light scattering
how can you modify the ceramic surface to make it more retentive prior to using silane?
hydrofluoric acid
chemically, how does a silane coupling agent work when bonding composite to ceramic
hydrolysis -> condensation -> polymerisation
dual bonding mechanism
methacrylate group that covalent bonds with resin through free radical polymerisation
alkyoxyl groups bonds with hydroxyl groups on ceramic surface
what is the function of silane in a composite restorative material
improves bonding/adhesion
enhances mechanical properties
how is porcelain surface prepped in a lab for bonding
etching with hydrofluoric acid
what do you use to bond porcelain to composite luting resin
silane coupling agent
when would you use a dual-cured material
thick material [procelain etc]
metal restoration
why would you still light cure a dual cured material
properties are reduced by 25% if not dual cured
types of veneers
porcelain, composite
gold
what would you do to a metal in a lab to prepare
sandblast
what chemical agent used to bond metal
MDP, 4-META
What metal can be used for an acid-etch retained bridge
NiCr, CoCr
anatomical landmark for the post dam
vibrating line
components of stainless steel and percentage
iron 72%
chromium 18%
nickel 8%
titanium 1.3%
carbon 0.7%
describe work hardening
strengthening of metal via plastic deformation
crystal structure dislocation, dislocations interact and create obstructions in crystal lattice, resistance to dislocation formation develops
increased strength and hardness
springiness
ability of material to undergo deflections without permanent deformation
disadvantages of self cure PMMA
high shrinkage
high thermal release [exothermic]
poor abrasion resistance
residual monomer which may be toxic
poor compressive/tensile
MOD Bell Glass Inlay - how to determine impression is usable
no airblows
ensure impression not seperated from impression tray
full cuspal coverage
gingival margin recorded
no tears
list 4 faults with impressions
airblows
voids
dragging
tear upon removal
no adhesive applied prior
how would you decontaminate an impression
rinse under cold water
place in perform for 10 mins
sodium benzoate
take out, rinse, wrap in gauze, place in bag and send to lab
