Endodontic Materials Flashcards
why are metal files used
remove soft and hard tissues
remove microorganisms
create space for disinfectants
create shape for obturation
what is stress concentration point on a file
abrupt changes in geometric shape of a file that leads to higher stress at that point
what is work hardening
strengthening of a metal by plastic deformation
crystal structure dislocation
what is nitinol
alloy of nickel and titanium
what does irrigation do
facilitate removal of debris
lubrication
dissolution of matter
penetrate to canal periphery
kill bacteria/yeasts/viruses
biofilm disruption
biological compatibility
what is responsible for antibacterial activity
hypochlorous acid made from sodium hypochlorite
what factors are important for sodium hypochlorite function
concentration
volume
contact
mechanical agitation
exchange
what is the smear layer made of
organic pulpal material and inorganic dentinal debris
what is the effect of the smear layer
bacterial contamination, substrate and interferes with disinfection
prevents sealer penetration
how do you remove the smear layer
17% EDTA
10% citric acid
what is the volume of sodium hypochlorite used per canal and for how long
30ml at least 10 minutes after canal preparation
what is the concentration of sodium hypochlorite used
3%
what does EDTA do
remove smear layer
what is the volume of EDTA used for canal
3ml
what is the concentration of EDTA used
17%
what are the properties of an ideal obturation material
easily manipulated
dimensionally stable
seals canal laterally and apically
non-irritant
impervious to moisture
unaffected by tissue fluids
inhibits bacterial growth
radiopaque
doesnt discolour tooth
sterile
what obturator do we use
gutta percha
what do sealers do
seal space between dentinal wall and core
fills voids in canal
lubricates during obturation
what are the properties of an ideal sealer
exhibits tackiness to provide good adhesion
establishes hermetic seal
radiopacity
easily mixed
no shrinkage on setting
non-staining
bacteriostatic
slow set
insoluble in tissue fluids
tissue tolerant
soluble on retreatment
what sealer is used
zinc oxide and eugenol
glass ionomer
resin sealers
what are the advantages of epoxy resin sealers
paste-paste mixing
slow setting
good sealing ability
good flow
initial toxicity declines after 24hrs
why are sealers containing paraformaldehyde not acceptable
they have severe and permanent toxic effects on periradicular tissues
