Endodontics
Course Review
Enoch Ng, DDS 2014
[Cold] Lateral compaction
Advantages
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Good length control
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Easier to adjust mid-obturation
Disadvantages
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Difficult to fill canal irregularities (internal resorption)
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Difficult in open apex cases
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Limited in severely curved canal (poor spreader penetration depth)
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Complete preparation
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Dry and inspect for tissue removal and smooth, well-shaped walls
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Check preparation flare (place MF finger spreader into canal – should go to within 1-2mm of CWL)
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Select master cone (in relation to MAF), fit to working length, radiograph to confirm seated to length
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If goes past CWL
Try another cone of same size (tolerance range)
Trim MC
Try larger size MC
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Place sealer on master cone and seat MC into position
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Use size MF or F NiTi spreader
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Place finger spreader alongside master cone to within 1-2mm of CWL – compaction of apical GP
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Use NiTi’s carefully – cannot be pre-curved, may buckle under pressure
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Measure an accessory point matching size of spreader (or 1 size smaller) to length spreader was placed
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Remove spreader, place accessory cone coated with sealer to length
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Repeat until spreader no longer goes beyond coronal 1/3 of the canal
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Take a pre-sear radiograph to ensure length and density of obturation is adequate
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Sear off (200
o
C) and remove excess GP to level of CEJ with System B heated plugger
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Apply light vertical pressure with pluggers – oppose GP’s shrinkage on cooling
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Clean out excess GP with ^OH on microbrush/cotton pellet
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Place final restoration/temporize
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Take post-op radiographs
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If canal was improperly prepared, spreader placement may have excess pressure and fracture the root
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Must pre-fit pluggers to avoid excessive lateral pressure on roots
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If canal is curved, NiTi finger spreaders create less stress and penetrate farther than SS spreaders
Goals of Obturation
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Root canal fillings – completely homogenous mass fills prepared canal in all 3 dimensions
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Presence of voids may provide leakage avenues and give way to bacterial regrowth/reinfection
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Radiographic evaluation criteria
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Length, taper, density
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Removal of GP and sealer to CEJ level in anterior teeth, canal orifice in posterior teeth
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Adequate temporary/definitive restoration
Removal of GP for post placement
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Safest to remove with warm instrument
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Removal does NOT affect obturation success, so long as apical 4-5mm remains intact
Coronal Seal
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Root canal is not finished until final coronal restoration is placed
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Full coverage indicated for posterior teeth
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teeth with poor restoration resulted in more teeth with periradicular lesions than poor endodontic fills