Dental pt6 Flashcards
Class of impression material
elastic
non elasric
impression material non elastic ex
gypsum (plaster)
guttapercha
dental impression compound
waxes
ZnO eugenol
(mention impression material -> impression compound, wax, gutta percha ; think of impression non elastic -> gypsum +ZnO eugenol -> dental impression + wax +gutta percha +gypsum + Zn eugenol)
Impression material elastic ex
Hydrocolloids
Non aq elastomer
(impression elastic -> 1 is like water, 1 doesnt
-> hydrocolloids
-> non aw elastomer)
Classification hydrocolloids
reversible: agar
irreversible: alginate
(hydrocolloids -> think of water -> agar - alginate)
(agar -> edible -> reversible -> can be eaten - cen be thrown up)
Classification non aq elastomer
silicon
polyester
polysulfides
(impression non aq -> no likes water
-> boobs dont like water -> silicon
-> poly stuff - polyester, polysulfides)
Charac alginate
use for removable denture (alginate aka alternate aka removable)
water evaporates -> hardens
tear easily
unstable dimention
elastic recovery (elastic impression -> elastic recovery)
cheap
Charac agar
full mouth impression (agar -> food -> edible -> full mouth -> full mouth impression)
highly elastic, flexible (elastic impression -> elastic)
NO odor
NO toxic (food -> NO odor, NO toxic)
Charac Silicon
best detail caption
high strength
elastic
NOT rigid
expensive
(Silicon
->best type -> best detail caption
-> high strength
-> elastic
-> expensive)
Ways silicon poly.
Condensation -> ethanol by product ; setting shrinking (Add base paste + accelerator paste)
Addition - NO by product (add base paste to catalyst paste)
Types viscosity
- high (heavy body)
- medium
- low (light body)
Technique impression material
single mono phase impression
2 steps putty wash
1 step putty wash (double mix sandwich)
Steps of 2 steps putty wash tech
check again
try tray in mouth
adhesive to tray
isolate abudment teeth
heavy body mixing onto tray
tray in mouth - NO move
clean mouth
evaluate impression
remove undercut areas
separate trays place light body
put in mouth - NO move
clean
evaluate
disinfect
Charac polyether, polysulfide (elastic)
Polyether > good detail caption than polysulfide
Polyether > expensive than polysulfide
fixed denture
high strength
hydrophilic - can have deep mouth impression
easy remove
max 1hr until (+) impression make
Layers porcelain
Opaque layer (oxide layer) -> biscuit bake 10min
Base layer at low temp (thick, > translucent)
Incisal/Translucent (enamel like) layer for shine (glaze bake)
System to make porcerlain crown
Cerec system - scanning machine -> optical impression
Procera sys milling ceramics
CAD-CAM
Ad all ceramic crowns
stable
biocompatible
high resistant to wear, distortion
aethetics
Dis all ceramic crown
brittle
small flaws -> propagate -> create cracks
(ceramic -> easy to break -> brittle )
Func porcelain
denture teeth
porcelain enamels (cover metal cap)
all ceramic crowns (jacket crown)
(porc - aesthetics -> cover
-> cover metal cap - porc enamels
-> jacket crown - all ceramic crown)
All-ceramic crown
All ceramic crown: jacket crown
No ceramic core:
- Castable: Na2O, CaO (via lost wax process)
- Pressed glass: IPS1 (High leucite) ; IPS2 (Lithium disilicate)
Ceramic core: Milled/ CAD CA,: Al2O3 core; ZrO2 core
(No ceramic core -> can be put into oven -> castable NaCa -> Na2O, CaO)
Ad of glass porcelain
strong
aesthetic
Chem composition porcelain
SiO2
high melting point - additives -> reduce
ranges melting point
(Porce - beautiful - remsembles glass -> SiO2 -> high melting range)
Ranges melting point porcelain
High fusing - 1300
Med fusing - 1100 - 1300
Low fusing - 850 - 1100
Ultra low fusing (most preferred) - 850
Biocompatibility
interxn materials/ devices w/ body tissue, fluids
Stages injury
chemical lesion
func lesion
morphological (anatomical) lesion
Response to injury
necrosis
inflammation (immune respone)
variation of tissue - ex: dentinal tubules have local response
Content dentinal tubule
odontoblast process
serum (plasma) like material
Hyper sensitive pulp
damage to dentinal tubules, displacement serum material as effect on n. endings coming from pulp b/c external hydrostatic/ osmotic changes
Dentine permeability
diffusion thru dentinal tubules in form of fluid movement aka Convection transport
diffusion proportional to thickness dentin, size molecule transported
Biocompatibility test stages
initial
2nd
preclinical usage
Biocompatibility initial testing
- cell planting, growth - check if material inhibits growth cells ; check if material effects activity cells by checking if reduce MTT into MTT-formazan
- Membrane permeability - give tryphan blue -> check health of cells. Tryphan blue enter -> aka membrane injured
- Agar overlay - agar covers cells stained by natural red. If cells injured -> natural red leaks
- Dentin barrier - thin dentin btw material, cells. Check if diffuse thru dentin -> effect cells
- Chemotaxic effect/ immune response - not described in ANSI/ADA
Mutagenesis tesing (assay) use
ID carcinogenic materials - faster than animal testing
Tests of mutagenesis testing
Ame’s test
Style’s test
Dominant lethal test
Oral, intraperitoneal LD50 test
Ames test
Mutant salmonella typhimurinum
- NO live w/o exogeneous histifine
- Mutation -> mutant NO produce his again -> aka material mutagenic
(Ame -> to eat raw fish - no have salmonella -> ame: mutant salmonella typhimurinum -> NO live w/o exogeneous hist)
Styles test
Fibroblast NO grown agar gel - mutated does
Dominant lethal test
Spermatogenesis
Oral and intraperitoneal LD50 test
mixture injected into albino mice peritoneal cavity
2nd testing
aka animal testing
2nd testing steps
rub material in cheek hamsters
implant material in animal -> check rxn bone, CT
put material on skin guinea pigs -> check rxn
put on healthy monkey’s teeth -> check pulp irritation in class 5 cavity
implant into bone -> check mobility radiolucency, penetration (monkey alveolar bone)
Def corrosion
elements alloy ionise
Ex corrosion
Cu -> ionized -> release 2e- -> Cu2+ -> leaves alloy -> effect tissue
Compare corrosion single phase alloy, multiphase alloys
single phase alloys < 30X ionized mass then multiphase alloys
Element’s liability
high: Cu Ni Zn Ga Cd (liability high-> ciu nho day ga ch)
medium: Ag
low: Au Pa Pl (low -> augh PaPer -> Au Pa Pl)
Effect elements liability
elements effect other element’s liability
ex: Pa reduce liability Cu
What cause increase ionized released in corrosion
reduced pH
Biological rxn corrosion
bacterial adhesion
toxicity
subtoxic
allergy
Clinical symptoms corrosion
subjective:
burning
itching
taste
objective:
inflammation
ligua geographica
ligua plicata
linchen planus
Color def
light perception by Cones (eye’s receptors)
How to perceive light
Rods
Cones
Rods
scotopic vision - needs 1 photon (+) -> brightness
Cones
Phototopic vision - needs more photons (+) -> colours
Colours seen b/c
Phototopic vision - cones divided to 3 types based on light sensitivity: green red blue
humans ID light based on
electromagnetic energy
range electromagnetic energy
380-780nm
Tc Color
black body emits colors when temp changes
Attributes of color
hue
brightness
saturation
Hue
degree stimulus ID as similar/diff from other stimuli chromatic/achromatic
Saturation
intensity specific color (chroma) aginast gray when gray = 0 saturation
Color adaptation
brains adapted to cont. stimuli same spectrum -> less sensitive
Clinical correlations
teeth shads chosen while looking at gray-blue color time to time
lipstick - change perception color teeth
hospital surgeons wear green/blue -> see colours all the time -> brain > sensitive to red blood
Colour blindness types
Monochromatic
Dichromatic
Abnormal trichromatic
Monochromatic
0.003% female (2/3 main color NO active aka 1 active)
Dichromatic
2-3% men (NO 1 main color aka 2 active)
Abnormal trichromatic
5-6% all ppl (NO missing but addition in the brain NO good to 2nd colours ex: brown)
Colour mixing use
create new colours
Types mixing
additive
subtractibe
complex subtractive
Additive
retina stimulated by 2 diff wave length -> new color born
Subtractive
filt. -> light removed
Complex subtractive
artistic w/ pigments
Opaque material can
reflect - white reflects all color
remission - reflection in surface/ subsurface are
absorbs light (color) - black absorbs all colours
Translucent material can
transmit - color pass thru
Metamerism
matching color object w/ diff spectral power distribution
colour matched aka metamers
Why metamerism occurs
diff type cone - response to diff cumulative E
aka diff comb light
