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19 Cards in this Set
- Front
- Back
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Factors affecting fracture resistance and strength of teeth
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Anatomy
Occlusion Pathology Structure Restoration Endodontics |
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By what percentage does endo treatment reduce tooth stiffness?
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5%
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Occlusal cavity?
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20%
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One marginal ridge?
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46%
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2 marginal ridges?
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63%
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Dehydration
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does NOT produce degredation of physical properties of Dentin
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Protection of Remaining Tooth structure
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No remaining dentin should be less than 1mm in thickness in the horizontal or vertical dimension
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Ferrule Effect
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360 degree metal encompassment provided by the final restoration
Improved resistance to fracture with ferrule effects of 1.5-2.0mm in the vertical dimension |
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Transition Zone
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provides post with resistance to fracture by placing bulk at the junction between the post and core components
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Retention of the post
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directly related to the length
Success is predictable with dowel length of at lease 8mm and/or at least the length of the crown component and/or as much of the foundation sub-osseous as supra-osseous |
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Do posts make teeth stronger?
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NO
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When to use a post?
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Only when it is necessary to retain a core
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Post Retention
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&uarr post length and diameter can &uarr retention
Parallel posts are more retentive than tapered posts The luting cement used can affect retention |
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Post Resistance affected by
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amount of remaining tooth structure
post length and rigidity presence of antirotational features presence of a ferrule effect |
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Diameter of Post (Dowel)
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Post should be no wider than 1/3 of the tooth width
At least 1mm of remaining structure should remain around the circumference of the post hole |
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Post Design
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5mm GP seal required (3mm min)
Post should engage at least 1/2 of the structure supported by bone Dowel at least as long as the crown above Dowel below the alveolar crest should be equal to or greater than restored tooth above |
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Fiber Posts (carbon, quartz, glass, silicon)
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modulus of elasticity similar to dentin
allows flexibility w the root when stressed bonding b/t post and dentin required |
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Difficulty of Post Retrievability (Easiest to Hardest)
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Metal > Fiber > Ceramic > Zirconium
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Foundation Material
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Cast Gold
Amalgam Amalgam and Pre-fabrication Post Composite Composite and PFP Glass Ionomer Glass Ionomer and PFP |
