Core Restorations Post-Core Systems Flashcards
Core Restorations
(also known as foundations)
Replace missing tooth structure prior
to crown preparation
When is a core necessary?
1. “No preparation should be extended farther
into the tooth than – mm at the cervical
line or down – mm from the central fossa.”
2. “No wall of dentin should be reduced to a
thickness less than …”
3. If –% or more of the coronal tooth
structure remains, sufficient retention for a
single crown can be achieved by adding
retentive features to the preparation
1.5, 1.5
its height for sake of
retention.
50
Materials for Core Restorations
(3)
*Dental Amalgam Alloy
*Composite Resin
*Glass Ionomer/Resionomer
Amalgam Alloys
Advantages
(5)
*Easy to manipulate
*Favorable mechanical
properties (high compressive
strength, wear resistance, and
dimensional stability)
*Corrosion products
*Acceptable for areas difficult to
isolate
*Relatively inexpensive
Amalgam Alloys
Limitations
(4)
*Relatively slow setting amalgam alloys (set 15 min)
*Corrosion
*Do not adhere to tooth structure
*Require a certain thickness for strength
*Color
*Relatively slow setting
(2)
*Usually cannot be prepared at the same visit
*High copper spherical amalgam alloys (set 15 min)
*Corrosion
*May cause discoloration of tooth structure
Composite Resin Core
(5)
*Bond to tooth structure
(however the bond strength
to dentin is weak)
*Can be used in thickness
<1mm
*Rapid polymerization
- can be prepared the same visit
*Time efficient, economical
*Relatively easy to manipulate
Composite Resin Core
Limitations
(4)
*Bond strength to dentin is
weak, require mechanical
retention
*Very susceptible to
moisture contamination
*Require good isolation, the
core margins must be
supragingival (2 mm tooth
structure to provide a
ferrule)
* Polymerization shrinkage (microleakage)
Composite Resin Core
(3)
*Light polymerized composite resins (Hybrids)
*Chemically polymerized (i.e. ParaCore)
*Dual polymerized (light activated and
chemically polymerized)
i.e. FluoroCore (Dentsply Sirona)
Glass Ionomer Cements
& Resin Ionomers
(5)
*Glass Ionomer cements (also available Metal reinforced
glass ionomers)
*Resionomers/Hybrid Ionomers
Hybrid of traditional glass ionomer and composite resin
*Significantly inferior strength compared to
amalgam alloys or composite resins
*Water imbibition
*Recommended only for low stress bearing areas or
as block-out materials for undercuts
Retention of Core Restorations
“A core must be anchored firmly to the
tooth and not just placed to fill the void”
Retention is achieved most times with the
use of pins whether an amalgam alloy or
resin core is used.
SKIPPED
Threaded pins (TMS)
(3)
*Minuta (0.0135 inch)
*Minikin (0.017 inch)
*Minim (0.021 inch)
Pin Retention
*One pin per
missing cups/marginal ridge
*4 maximum
Pin Retention
*Location
*Ideally on —
*– mm inside DEJ for vital teeth
*No closer than – mm from the axial wall
line angles
0.5-1
0.5
SKIPPED
Amalgam Bonding
(5)
*Increase in retention is minimal
*Sealing of the dentinal tubules
*Decreases post operative sensitivity
*Increases tooth reinforcement
*Technique sensitive, little working time,
added cost
Core Restorations
(2)
*Preserve tooth structure where possible
*Maintain vitality of tooth where possible
Core Restorations
*Preserve tooth structure where possible
*Natural tooth is the strongest core material
*Maintain vitality of tooth where possible
*Success rates of vital teeth are significantly
greater than on endodontically treated
teeth
Core Restorations
*– mm of natural tooth height to provide
a ferrule
*Understand limitations associated with
each material and technique
2
Dowels - Posts
Dowel:
a post, usually made of metal
that is fitted into a prepared root
canal of a natural tooth. When
combined with an artificial crown or
core, it provides retention and
resistance for the restoration.
Dowels - Posts
FUNCTION of a POST
(3)
➢Anchor the core material with a
stable post
➢Restore missing tooth structure
➢Reinforce the tooth-restoration