Endodontics
Course Review
Enoch Ng, DDS 2014
Cleaning and Shaping
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Continuously tapered form that holds filling material within the canal
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Maintains original anatomy and conserves root structure
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Maintain position of apical foramen without over-enlarging
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Shaping facilitates cleaning
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Allows irrigant access
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File shape, irrigant cleaning
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Small file (scout access)
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Straight line access – may require coronal flaring
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Enlarge to size 20 for estimated working length (minimal file size)
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Irrigate
Gates Gliddens
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Side cutting
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Used for straight portion of canal
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Used serially and passively with successively smaller sizes at greater depths
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Used to brush away restrictive dentin and provide straight line access
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Irrigate after each GG use
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Cutting head diameters
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#2 – size 70
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#3 – size 90
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#4 – size 110
Shaping and Access
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Coronally, prepare AWAY from the furcation
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Be aware of danger zones
Mesial concavity of mesial root of Mn molars
Distal wall of MB root of Mx molars
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Anticurvature techniques
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Precurve files
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Instrument with pressure towards curve and coronally
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Balanced force hand instrumentation
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Checking canals
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CWL – usually #20 file, may be larger
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MAF – largest file used at corrected working length
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May want to use different files (K-files and hedstroms) to differentiate between canals in radiograph
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Improving cleaning
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Combining both hand instrumentation and rotary
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Apical Foramen Resorption – natural constriction may be destroyed
Set working length shorter = 1.5mm
May be difficult to obtain apical seat
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Apical stop – MAF and next smaller file do not go beyond working length
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Apical seat – MAF does not go beyond working length, but next smaller file does.
Resistance with smaller file is felt
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Open Apex – MAF goes beyond working length, no resistance is felt by smaller file
