Post and Cores Flashcards
What radiographic endodontic status would indicate a post placement?
Previously root treated
Good apical/coronal seal
Obturation within 2mm of apex
Well condensed
Periapical status
What aspects of root anatomy may indicate a post crown?
Wide roots
Minimum 1:1 root to crown ratio
Minimal or no curvature
No evidence of root resorption
What is the minimum length that a post must be able to extend to sub-crestal on a tooth?
At least 4mm sub-crestal.
What clinical endodontic signs may indicate a post crown?
No sinus
No abscess
Not TTP
No exposed GP
What are the restorative indications for a crown?
Caries free
Minimum 2mm ferrule extending at least around 3/4 of tooth
Minimum 2mm free occlusal space after core placement to allow for crown to be fabricated.
In group function.
What are the periodontal indications for placing a post crown?
No bleeding pockets >4mm
No pockets >5mm
No pus
BOP <15%
Tooth not mobile
No furcation involvement
List the advantages and disadvantages of a direct post.
ADV- Same day post placement, and lower cost.
DIS- Less accurate fit, not suitable for wider canals, no suitable if less than ideal ferrule remains.
List the advantages and disadvantages of an indirect post.
ADV- More accurate fit, suitable for wider canals, and impaired ferrules
DIS- Requires more appointments and costs more.
What types of materials can posts be made of?
Metal (Cast gold, SS, brass, titanium)
Ceramic (Zirconia, alumina)
Fibre (Glass, quarts, carbon)
Outline the advantages and disadvantages of a cast metal post?
ADV- Radiopaque, easy to retrieve, better fir to overlaying metal crown.
DIS- Poor aesthetics, risk of root fracture from transferred force, corrosion risk.
Outline the advantages and disadvantages of a ceramic post?
ADV - High flexural strength, greater aesthetics.
DIS - Difficult to retrieve, technique sensitive, difficult to spread silane coupling agent, requires a dry field.
Outline the advantages and disadvantages of a fibre post.
ADV- Allows light cure through post, mimics roots elasticity modulus.
DIS- Difficult to retrieve, technique sensitive, less radiopaque.
What is the benefit of a parallel post over a tapered one?
Less stress on root
Greater retention
What is the benefit of a tapered post over a parallel one?
More conservative.
What is the benefit of a smooth post over a serrated one?
Passive fit, less stress on root upon insertion, risk of root fracture.
What is the benefit of a serrated post over a smooth one?
More retentive.
What are the ideal post characteristics?
Parallel sided (more retentive)
Non-threaded (imparts less stress onto tooth)
Cement retained (acts as a buffer between forces)
What extra-oral landmarks do you look for when assessing for a post crown?
- Smile line
- Symmetry
- Incisal show
- Speech
- Skeletal pattern
- FWS
- TMJ
What intra-oral features would help you assess whether to place a post crown?
- Occlusion
- Excursions
- Guidance
- Periodontal status
- Caries status
- Overeruption
- Shade and shape
- Interocclusal space
- Ferrule placement
What are the risks of placing a post?
Perforation
Root fracture
Post fracture
Infection requiring re-RCT
All of which could then indicate XLA
Note that the risk are increased in bruxists, Class IId2, and Class III edge to edge malocclusions.
What are the ideal post lengths and widths for a post crown?
4mm sub-crestal post
At least same height of the crown
Ideally 2/3 root length, whilst maintaining apical 4mm
Width not greater than 1/3 root diameter
What are the preparation requirements for a post?
2mm high ferrule
4mm preserved apical GP to maintain seal
Width not greater than 1/3 root diameter
Outline the procedure for prepping a tooth for a direct post?
Assessment/consent/MH/Shade
Check occlusion and guidance points
Give LA and place dam
Remove previous restorations/caries
Refine crown margins
Calculate working length of desired post
Use GG 3/4 to prep 2mm of GP from canal
Use post system to create post space
Adjust prep to include ferrule, and other retentive factors
Outline the procedure for cementing a fibre post.
Irrigate post space with hypochlorite
Try in the post to assess prep
PA can be used to check
Use cement based on manufacturers instructions
Load the post space with cement, seat to prep margins
Remove excess cement
Prepare and redefine margins for crown prep
Take impressions for crown prep and provisional restoration.
Outline the procedure for taking the impression for an indirect post.
Complete prep
Wash prep with hypochlorite
Select tray
Insert impression post, blunt coronal for retention
Retract gingiva
Carefully wash and dry
One stage impression - light body around prep and post
Medium body over top
Take a bite reg and opposing arch alginate
Place temporary post inside prep
Complete composite core build up
Construct provisional restoration
