Restoration of Extensively Damaged Vital Teeth Flashcards
According to central core guidelines, the pulp and ____mm of surrounding _____ should be preserved
1mm; dentin
According to central core guidelines, retentive features should not be cut deeper than:
1.5mm at cervical line or central fossa (2mm)
According to central core guidelines auxiliary retentive features should ideally be kept in:
“safe zone”
According to central core guidelines- for caries removal, deeper areas should be:
filled with base
Avoid excessive tooth removal in the name of:
retention
Describe what happens to the pulp as we age?
shrinks
List the five categories to consider in decision making:
- type of restoration
- using defects as retentive features
- pin placement & retention
- bases & cores
- tooth preparation procedures
What questions should you ask yourself to determine the type of restoration to use when LARGE DECAY has destroyed the tooth structure:
- WHERE is the decay?
- How much tooth structure is remaining?
- WHERE is the remaining tooth structure ?
- Can I restore this?
- Should I restore this?
Extensive peripheral damage =
Full crown
What restoration would you choose based on the following image?
Full crown (extensive peripheral damage)
Isthmus destruction greater than 1/2 intercuspal width =
inlay or onlay
More than 50% of tooth structure is gone and loss of cuspal support =
crown (& likely a core build up too)
Less destructive central lesion =
inlay or onlay
Large central lesion =
build up & crown
Combined central & peripheral destruction -
core build up & crown (possible RCT/post)
When would you decide you needed RCT with combined central & peripheral damage?
- if pulp is exposed
- if post is needed for retention of build up
Often, a tooth preparation will need to be modified by adding retentive features to:
increase retention & improve resistance form
List some examples of retentive features used to modify a prep:
- re-orientatino of sloping surfaces
- adding grooves
- adding box forms
- adding pins with a buildup
T/F: There are times when leaving a crown prep without a buildup I can help with retention too. Sometimes you need to leave it ugly
True
What can we do to increase resistance form with “less-than-ideal” tooth structure remaining?
- Reduce TOC of axial walls
- Add grooves
- Add box forms
- Increase wall height
What are ways to increase wall height of a prep, in order to increase resistance form with less-than-ideal tooth structure remaining?
- place finish line more apical
- pin retained core
- crown-lengthening
- orthodontic extrusion
Increased axial reduction in the cervical 1/2 of the preparation wall will:
Reduce taper & create more retention & greater resistance form
Grooves should be placed ______ when trying to increase retention & resistance
parallel to long axis of tooth
Grooves should be placed parallel to the long axis of the tooth with the following requirements:
1) at least 1mm wide & deep
2) 0.5-1.0mm away from finish line
3) spaced around the tooth
Proximal grooves _____ the radius of the arc of rotation
shorten
Walls of a groove or box are best placed ______ when in a short preparation with minimal occlusal clearance
perpendicular to the displacing forces
- Remove caries
- Convert caries removal into a box for by squaring walls
- Not need on intact walls
- Box should be well into dentin (deep enough) to resist displacing forces
What is being described? What is this used for?
Box form used for retention
Why should the box form be placed well into dentin?
To resist displacing forces
Box forms can aid in:
Retention & resistance
When two boxes are needed, less than 180 degrees of tooth circumference remains. Why is this significant? What should you do in this situation?
Great risk for cuspal fracture; use a build-up & full crown to protect against fracture
The following aid in _____
- sloping walls
- box form
- grooves
retention
When increasing the wall height through placing the margin more apically, often this is below the gingiva, however we must:
avoid invading biological width
When adding material to “build up” the tooth, this can give more wall. Remember the ____ needs to be on tooth structure & you still need at minimum ____ of ferrule
finish line; 2-3 mm
How might you remove the biological width restriction?
Crown lengthening
Extruding the tooth out of the bone to gain height:
Orthodontic extrusion
What procedure had the effect seen in the following image?
Crown lengthening
Where can the margin be placed if you are trying to increase the wall height?
More apically (below gingival line)
Also called a foundation restoration:
Core build up
Replaces lost tooth structure to improve retention of a crown:
Core build up
A _____ must be anchored firms to the tooth & not just be placed to fill the void
Core build up
Retention for a core is often with the use of:
pins
A build up is needed when _____ of the tooth structure is lost
more than 50%
What would be needed to crown the tooth in the following image?
Core build up
Describe what is occurring in the following images:
- not enough tooth structure for crown retention
- build up added after crown lengthening
- success
What happens to a crown when the prep has short axial walls?
Repeated de-cementation
When there is excessive interocclusal distance (tall crown height) this needs:
pin-retained core
Crown margin (finish line) needs to be on _____ or prognosis of restoration will be compromised
sound tooth structure
What is the difference between amalgam core build ups and composite core build ups?
Amalgam core build ups= STRONG (but not retentive)
Composite core build ups= RETENTIVE (but not as strong)
Use of pins is recommended when:
1/2 or more of the clinical crown has been destroyed
Cusps thinner than 1/2 their height are considered weak and should either be:
shortened or removed
For amalgam core, the cavity floors and walls should be:
flattened
Crowns margins should be at a minimum _______ to build up material margin
1mm apical
What are the mechanical properties of an amalgam core build up?
- compressive strength
- dimensional stability
- corrosion- sealing
What are the limitations to an amalgam core buildup?
- matrix placement can be difficult
- slow setting material
- no bonding or natural retention
- requires at least 2mm thickness
- color shows through some ceramic crowns
- final crown prep occurs another day
List the mechanical properties of a composite core buildup:
- bonds to tooth structure
- still needs help with pins
Three advantages to a composite core build up (compared to amalgam core build up) include:
- quick setting
- can be thinner than 2mm
- color of material aids in crown matching
Your patient needs a core build up and crown in the same day, what material will you use?
Composite (Amalgam takes more than one visit)
Limitations to composite core buildups:
- technique sensitive
- isolation can be challenging
- micro leakage possible as material shrinks when cured
_____ are helpful to support the build up material when residual tooth structure does not provide adequate retention itself
pins
pins increase _____ for buildup support
resistance
Where do pins increase the resistance of the core buildup?
Both internally & apically
T/F: Pins should be placed parallel
False- they should be place non-parallel
What are the guidelines for pin placement?
- place in sound, healthy dentin
- do not damage or undermine nearby enamel
- avoid perforation of pins into pulp
- best used in line angle of posterior teeth
- 1 pin per missing cups, line angle or axial wall
- atleast 5 mm of space between pins
- max of 4 pins per tooth
It is important to not damage or undermine nearby enamel when placing a pin, how can this be accomplished?
1) flat area of placement
2) 0.5-1mm from DEJ or axial wall
3) atleast 0.5 mm of dentin should surround the pin
Pin placement procedure:
- use ____ to make ____
- used with ____ hand piece
- watch ____ & ____
- pilot drill; pilot hole
- slow speed
- angulation & position
-cutting tip & helical flutes
-2mm deep (threaded pins)
-one motion without stopping
-too much wobble or imperfect handpiece technique creates a pilot hole that is too wide
this describes:
Self-limiting twist drill (for pin placement)
T/F: Pins often need to be bent to help created non-parallelism and to create even more retention
True
Pins placed into dentin should be
1) _____ deep into the dentin
2) _____ coronal into buildup
3) minimum ____ radius of buildup still around pin after prep is done
1) 2mm
2) 2mm
3) 1mm
What pin compilation is seen in the following image?
Fluted root shape
What pin compilation is seen in the following image?
Furcation
What pin compilation is seen in the following image?
Pulp penetration (RCT needed)
How would you resolve the following pin complication?
-Pin into pulp
RCT needed
How would you resolve the following pin complication?
-Pin exits tooth surface above bone
Flap & smooth to tooth contour
How would you resolve the following pin complication?
-Fractured pin
Move to another location 1.5mm away
How would you resolve the following pin complication?
-Stripped pin (loose pin)
Use larger size of pin
______ are used only to protect pulp in teeth that have excavation that are deep & near the pulp
bases
When are bases used?
Only to protect pulp in teeth that have deep excavation near the pulp
Bases can be used to fill in ____ when an entire buildup is NOT needed
undercuts
Bases are ____ material that do NOT provide ____ like a build up
Weaker; strength
Bases are NOT strong enough to:
support grooves, boxes or other retentive features
_____ material protects the pulp and provides smooth, flat pulpal floor
base
What materials are used as bases? (4)
- Polycarboxylate cement
- Glass ionomer cement
- Resin-modified glass ionomer cement (RMGI)
- Silver-reinforced glass ionomer cement (Ketac-Silver)
CaOH (Dycal) is an example of a:
liner
If used, a liner is placed:
under base
Give an example of the common protocol used with bases:
- gluma (gluteraldehyde) 2x60 seconds
- Dycal (CaOH)
- Vitrebond
- Glass ionomer
- Routine restoration steps
What can be seen in the following images? What does this aid in?
Orthodontic extrusion - increase in wall height for retention
In the process of restoring extensively damaged vital teeth, prior to prep:
Evaluate periodontal & endodontic health
In the process of restoring extensively damaged vital teeth, prior to prep, if periodontal & endodontic health is nonvital, what should be done?
RCT
In the process of restoring extensively damaged vital teeth, prior to prep, after evaluating periodontal & endodontic health:
remove all caries
