Endodontics
Course Review
Enoch Ng, DDS 2014
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File separation factors in operator control
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Rotational speed – increased RPM = increased separation rate
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Operator experience
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Apical pressure – increased pressure = increased separation rate
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Instrument taper – increased taper = decreased time to separation
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Factors out of operator control
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Canal curvature – radius curvature decrease = decreased time to fracture
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If unable to bypass/remove file, or if patient has symptoms, can do surgical root canal
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Open a flap, open the bone, reveal root apex and remove file from bottom of the root
Irrigants/Lubricants
Instruments shape, irrigants clean
Canal shape is variable, some areas cannot be instrumented
Irrigant should be deposited to fill half way up the pulp chamber
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Use only side vented needle – prevents NaOCl exiting apex
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Never bind tip in the canal – always keep it in motion
Flush chamber first, then canals
Irrigant only works 1-2mm ahead of the tip
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Gentle pressure – flushes back out access
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Measure – use stopper or bend to 2-3mm short of CWL
NaOCl accidents are SERIOUS – edema, hemorrhage, pain, risk of infection
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Passive ultrasonic irrigation (PUI)
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File is ultrasonically activated in irrigant filled canal
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Creates acoustic streaming of irrigant
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1min of PUI after hand/rotary cleaning/shaping 7x more likely to yield negative culture than hand/rotary
instrumentation by itself
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EndoVac
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Negative pressure irrigation
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Facilitates delivery of irrigant to working length, potential to reduce accidents
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Significantly better debridement of apical 1mm than need irrigation
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Lubricant allows for more efficient instrumentation – RC prep, glycol, urea peroxide, EDTA chelating agent
New developments – K3XF, R-phase technology, K3 cross section
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Vortex file – processing of M-wire gives microstructure containing marsenite
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Possibly alloy strengthening, increased cyclic flexure fatigue resistance
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Sybron (twisted file) – R-phase heat treatment optimizes strength and flexibility of NiTi
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TF cutting flutes created from twisting (not grinding) the file
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Can withstand significantly more torque
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Significantly better resistance to cyclic metal fatigue than NiTi’s manufactured from grinding
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PathFile – rotary file used to establish canal patency (used after #10file to get working length)
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Apical sizes 13, 16, and 19
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Significantly less modification of curvature and fewer canal aberrations
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Self-adjusting file – hollow and thin cylindrical NiTi lattice, adapts to cross-section of root canal
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Single file used through entire procedure (after a glidepath with a #20 K-file)
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Preparation with similar cross section but larger dimension than original canal
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Constant irrigant flow
