Endodontics
Course Review
Enoch Ng, DDS 2014
File Types
K3 files
Properties
Band coding
Design features
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3 radial lands
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Positive rake angle, non-cutting tip
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Lengths 21mm, 25mm, 30mm
Properties
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Passive, reaming dentin removal
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Low tendency for canal transportation
-
Leaves a thick smear layer
-
300-350 RPM recommended
Top band – taper
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0.4 – green
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0.6 – orange
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0.8 – blue
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1.0 – pink
Bottom Band – ISO tip size
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20 – yellow
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25 – red
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30 – blue
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35 – green
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40 – black
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45 – white
Rotary files
Protaper files
Profile
Profile
Design Features
-
3 radial lands
-
Negative rake angle, non-cutting tip
Properties
-
Passive, reaming dentin removal
-
Low tendency for canal transportation
-
Leaves a thick smear layer
-
150-350 RPM recommended
Design features
-
No radial lands
-
Negative rake angle, non-cutting tip
Properties
-
Active cutting dentin removal
-
Higher tendency for canal transportation
-
Thin smear layer, less debris remaining
-
150-350 RPM recommended
Procedural Errors
o
Informed consent before starting, inform patient of referral cases
o
Inform patient of complications immediately
o
Document incident in records
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Danger zone – apical/middle third of root close to furcation, where dentin/cementum is thin
o
Safety zone – opposite side of danger zone
o
Easy to perforate laterally into danger zone when instrumenting
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Perforation
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Zipping – in a curved canal, apex is opened up from file trying to straighten itself out during over
instrumentation by/beyond apex
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Instrument separation - prevented by
o
Avoid placing excessive stress
o
Use instruments less prone to fracture
o
Follow instrument use protocol
o
Assess canal curvatures radiographically before beginning
o
Open orifice before negotiating canals
o
Create adequate glide path with hand files
o
Use low rotation speeds and torque levels
o
Use crown-down technique
o
Irrigate/lubricate during instrumentation
o
Use pecking/pumping motion (K3 and K4 motion is in-and-out)
o
Practice new systems/techniques on extracted teeth first