Endodontics
Course Review
Enoch Ng, DDS 2014
Posts
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Aid in retention of core/restoration
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Weaken tooth structure (loss of dentin) – they do NOT strengthen tooth
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Increases likelihood of tooth fracture and perforation
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Post length = crown height, or ½ root length
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Remove gutta percha with heated instrument
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No post has achieved fluid tight seal – 5mm gutta percha should remain for apical seal
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Use smallest post possible – 1.5mm dentin surrounding post on all sides
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Knowledge of root anatomy essential for successful post placement
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Mx incisors – sufficient bulk to support post
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Mx canines – wide facial/lingually
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Mx premolars – roots curve distally, taper rapidly, buccal root has canal invagination 83%
Place post in palatal canal
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Mx molars – 85% palatal canals curve facially
Not visible radiographically, but invaginations on facial aspect of palatal canal
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Mn incisors – higher success without post/core, thin mesial/distally
Invaginations common, multiple roots common
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Mn premolars – lingual inclination of roots (caution for facial perforations)
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Mn molars – roots thin mesial/distally, invaginations are common, danger zone
Place post in distal canal
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Success rate
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Anteriors – no advantage for coronal coverage – composites work equally well
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Posteriors – no advantage for posts – coronal coverage increases success rate
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Exception – RPD patients
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Types of Posts
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Threaded – most retentive, causes root fracture
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Tapered – least retentive, most dentin conservative
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Parallel – middle ground
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Bonded fiber – conservative prep, 1 visit placement
Post length can be conservative, bond aids in retention/seal
Favorable fractures
Isolation with rubber dam still needed
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Cast posts
Impossible to exclude bacteria during temporization period
Unfavorable fractures
Fabrication nearly impossible while maintaining isolation
Posts Summary
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Case selection – know anatomy, keep dentin removal to minimum, anticipate potential complications
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Posts should be reserved for limited clinical scenarios
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Bonded fiber posts under RDI is preferred
Restoration Summary
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Rubber dam isolation, conservative tooth structure removal
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Intact anteriors don’t need a crown (can use composite), but posteriors do require cuspal coverage
