Lec Endo Material 2 Flashcards
12 steps to endo:
dx, infection control, access, debridement, WL instrument, canal prep, irrigation, drying, medicamentation, temp, obturation, resto
When to use screw in slow speed with torqu multiplier:
rotary files
slow speed arrangement for GG:
normal head, no torque multiplier
How many times slower does the torwue multiplier make the slow speed?
64X slower
Creator of first endo file:
Ed Maynard
Most commonly used stainless steel hand files:
K-files
Hand file sizes:
10-100
Size of tip of 100 file:
1mm
Size of tip of 10 file:
0.1mm
How to figure out the size of the tip of a file:
move decimal point of the size of the file 2 digits to the L
Diameter of file increases by:
0.02mm/mm starting at tip
Length of flute of files:
16mm
D0:
initial diameter
Name the parts of the hand file:
tip, flute, shank, handle
Organization that regulates file size:
International Standardizatoni Organization (ISO)
Name the 2 white hand files:
15, 45
Name the 2 green hand files:
35, 70
Name the 2 red hand files:
25, 55
Name the 2 black hand files:
- 80
Name the 2 yellow hand files:
20, 50
Name the 2 blue hand files:
30, 60
Color of 8 file:
gray (special size)
Special size files:
6, 8, 10, 12 (pink, grey, purple, orange)
How to choose file length:
tooth location in mouth, access, root length
Available file lengths:
21, 25, 31mm
Length of most spiral cutting edges of hand files:
16mm
Active part of hand file is almost always this length:
16mm, length of shank changes
Define taper:
the rate of inc of X-sectional diamter
ISO taper for manual files:
0.02
D0 for a 25 hand file:
.25
D1 for a 25 hand file:
0.27
D3 for a 25 hand file:
0.31
D16 for a 25 hand file:
0.57
Avg taper of a root canal:
0.02mm/mm
TF? Rotary files have the same taper as hand files.
F
Files w different tapers have the same:
tip diameter
Sharp angle at tip of file indicates:
cutting tip
Fxn of non cutting tips:
guidance
When to use non cutting tips:
less engagement of dentin, prevents transportation
Files w tips that are non-cutting at UB:
15-80 files
non-cutting tip is aka:
Roane tip
TF? 8 and 10 files at UB are cutting.
T
Files with this type of transverse cross-section are more cutting:
sharper angles
transverse cross-section shaper that leads to less friction and more debris removal:
triangle (60’)
transverse cross-section of most K-files:
square (90’) miles
TF? The sharper the angle, the larger the angle.
F. the smaller
Adv of stainless steel files:
resistant to corrosion, sterilizable, can prebend, rigidity increases w sized
Composition of stainless steel files:
74% Fe, 18% Cr, 8% Ni
Composition of nickel titanium files:
56% Ni, 44% Ti
This provides torsion for hand files:
twisting of flutes (check)
3 types of hand instruments:
Barbed Broaches, Reamers, Files
Barbed broaches engage:
tissue only, removes cotton pellet, weaker instrument, fracture
Use barbed broaches for:
pulpectomy
Beware of this w barbed broaches:
will break if you touch the walls, never use in curved canals
Reamers, cutting tip or non-cutting tip?
cutting tip
TF? Reamers have fewer flutes that K-files.
T
How do reamers cut?
rotational motion
Do reamers have inc or dec flute space?
inc (fewer flutes)
K-files, cutting tip or non-cutting tip?
cutting
When do K-files cut?
insertion, withdrawal, clockwise and counterclockwise rotation
Ideal way to enter canal:
little pressure, cut on the way out
When do hedstrom files cut?
only w filing motion
Hedstrom files:
ground spiral, aggressive cutting
Are Hedstrom files more or less prone to separation?
more
TF? You should only use a reaming motion with Hedstrom files.
F. never use reaming motion
Design of Hedstrom files:
dec diamater
TF? Hedstrom files can be used to remove pulp.
T
Flex-R, aka:
Roane tip
Are the tips of Flex-R files cutting or non-cutting
inactive, (non-cutting)
Are Flex-R files grounded or twisted?
grounded
Adv of NiTi files:
shape memory, superelasticity, resistance to cyclic fatigue, less cutting efficiency
K files, more or less resistant than reamers?
less
K file are only for:
cleaning
Better flexibility, stainless steel or NiTi?
NiTi
Heated martensite becomes:
austenite
Undergoes deformation more easily, austenite or martensite?
martensite
More resistant to fatigue, NiTi or SS files?
NiTi
Less cutting efficiency, NiTi or SS?
NiTi
More efficient overall, NiTi or SS?
NiTi
32:1 reduction contra angle, more or less susceptible to fracture:
more
Benefits of engine drive rotary instruments:
speed and torque control
% fracture rate of NiTi hand instruments:
5%
Effect of Nickel titanium rotary instrument fracture:
complicate or compromise RCT outcome
3 main factors, clinical performance of NiTi depends on:
Design, Alloy/Manufacture, methods of use
More susceptible to fracture (rotary NiTi):
Reduction Contra Angle (check)
Lower taper, more or less space apically?
less
What does less space apically mean”?
more debris can be forced apically
TF? Higher tapers will cut more dentin coronal to point of contact.
T
Variable taper files:
protaper
Constant taper files:
profile
Benefit to Protaper Gold:
metallurgical enhancement via heat tx technology, flexibility, memory (prebend), cyclic fatigue
Portion of the canal shaped by S1 and S2:
cervical and middle
Width of rubber stopper:
1.5mm
Clean stands should be filled w this in cx
sodium hypochlorite (disposable sponge)
How far to insert paper points:
to WL
Obturation materials:
sealer, core (GP), instruments, devices
Ideal fitting material:
easily places and removed, seal apically & laterally, no shrinkage, solid after insertion, impervious to moisture, doesn’t stain tooth, RGO, bacteriostatic, doesn’t irritate periapical tisue, sterile or sterilizable
