Endodontic materials Flashcards
2 materials used for endo instruments
nickel titanium
stainless steel
what does the size of a hand instrument represent
the diameter of the tip
what size is the tip on a size 10 hand file
0.1mm
how much bigger is D16 to D0
0.32mm greater
what is the tip angle on a hand instrument
75 degrees
what is the taper on a SS hand instrument
0.02
2%
what does a taper of 0.02 mean
every 1mm towards the shank, the diameter increases by 0.02
what are the available lengths of SS files
21, 25 or 31mm
what is the consistent working length of SS hand file
16mm
what is the increase in diameter from file to file, from sizes 10-60
0.05mm
what is the size increase from file to file, from sizes 60 - 140
0.1mm
SS hand file metal composition
10.5% chromium
disadvantages of SS hand files
poor flex
advantages of SS hand files
dont corrode rust or stain
types of SS files
K file
flexofile
hedstrom file
what are barbed broaches used for
removing pulpal tissue - not suitable for narrow, curved canals
flexofile use
preparation of glide path
apical gauging
negotiating ledges
tip on a flexofile
nonaggressive (batt)
what motion are hedstroem files used in
up and down motion due to stiffness
when are hedstroem files used
only in retreatment to remove GP or an overfilling of root canal
as the file cuts when moved in the coronal direction
what do NiTi files require
torque control motor
metal composition of NiTi
56% nickel
44% titanium
what are the new NiTi files made of
M wire
what are the 3 crystalline phases of M wire
deformed and microtwinned martensite
premartensitic R-phase
austenite
advantanges of M wire
greater flex
increased safety
by how much is cyclic fatigue improved with M wire
400%
rotation speed and torque of proglider
300 rpm
torque 2
what lengths are protaper gold instruments available in
21mm
25mm
31mm
what is used as an interappointment medicament
non-setting calcium hydroxide paste
pH of calcium hydroxide
12.5-12.8
commercial names of CaOH
hypocal
ultracal
symptoms of a canal with exudate
TTP and tender to percussion
discharge present at each canal opening
apexification
open apex tooth is filled with calcium hydroxide to stimulate the formation of a hard tissue barrier at the apical portion of the root
indications for apexification
vital radicular pulp in an immature tooth pulpotomy
if vital pulp tissue is present apically
pulpless immature tooth with or without periapical radiolucency
horizontal root fracture (80% success)
what is used for apexification
mineral trioxide aggregate
what would be used to induce hard tissue formation in the presence of iatrogenic perforation
CaOH
Internal resorption tx
if not perforated - extripate pulp, dress CaOH, obturate with warm GP
if perforated - defect sealed, surgically or with MTA
what does internal resorption present as
pink spot
types of external resorption
surface resorption
inflammatory resorption
replacement resorption
pressure resorption
systemic resorption
idiopathic
tx for non vital immature permanent incisors
apexification
apical barrier
revascularisation
GP composition
19-22% gutta percha
59-75% zinc oxide
waxes, coloring, antioxidants and metallic salts
what is GP
trans isomer of polyisoprene (rubber)
what are the 2 forms of GP
beta phase - solid
alpha phase - heated, becomes soft
GP disadvantages
shrinkage on cooling
poor adhesion to dentine
cant be heat sterilized
types of sealers
zinc oxide eugenol
calcium hydroxide
GI
epoxy resin
Types of calcium silicate cements
1st gen - MTA
2nd gen - biodentine, bioaggregate
