02 SSC Flashcards
What are the indications for SSCs
Large lesions Rampant Caries Following Pulp Therapy Teeth with developmental defects Fractures teeth Temporary restoration of young permanent teeth
Why are SSCs indicated for large multi-surface lesions
Because they historically have a high failure rate
What teeth have an especially bad track record for multi surface restorations
Mandibular first molars
Why might behavioral issues be an indication for an SSC instead of a restoration?
Because if they child is so bad that they need to be sedated, you only want to do the procedure once
What are the numbers as far as comparing SSCs to multi-surface amalgams?
70% of 2-surface amalgams need replacement before the age of 8
Only 12% of SSCs ever need further treatment
List the order of restorative reliability from best to worst
SSC>Amalgam>Composite>GI
Which restorative material has the worst survival rate
GI
What is the armamentarium for SSCs
Assorted crown sized
Crown contouring pliers
Crown crimping pliers
Crown scissors
Heatless stone
Rubber Wheel
Why might anesthesia be required, even following pulp therapy
comfort due to damage to gingiva
Why should a rubber dam be used
Controls
Moisture and Contamination
When should the rubber dam be removed
To check occlusal reduction and occlusion
May be needed to make proximal slice
What are the four principles of tooth preparation
- Remove all evidence of caries
- Remove loose and overhanging tooth structure
- Place any needed liner or supporting base
- Complete any needed pulp therapy
What should be measured before the SSC preparation
mesio-distal width in order to select the correct sized crown
What bur should be used to reduce the occlusal surface
Large flat fissure bur
Large Round bur
What are the three steps to complete the occlusal reduction
- reduced groove
- cusp tip
- cusp slope
How much should the occlusal be reduced in order to have enough clearance
1-1.5 mm
What is the most important part of the preparation
the proximal reduction
What feature will prevent the seating of the crown
a proximal ledge
What are three keys to the reduction of the proximal surface
- Protect adjacent tooth
- Beveled buccal surface
- Preparation below gingival crest
What do you need to check for after the proximal reduction
- Probe to check that there is no ledge and enough clearance for the crown
- Make sure there is the proper amount of proximal clearance
What must be done in order to avoid leaving a ledge
the proximal slice must extend sub-gingivally
What are 4 keys of a complete preparation
- Contact broken
- Material removed
- Occlusal reduction
- Proximal reduction
What are the three steps to put finishing touches on the preparation?
- Bevel the occlusal-facial and occlusal-lingual line angles
- Round the gingival border of the bevel
- Round the proximal-facial and proximal-lingual line angles
What are finishing touches 4-6
- Round sharp edges of enamel
- check for adequate occlusal and proximal clearance
- check for proximal ledges
What are the three types of ssc crowns that we can choose from
- 3M ION Pre-fab
- 3M Unitek
- Denovo
What are the advantages of the 3M ION Pre-fab crowns
- Pre-trimmed, belled, and crimped
- Requires minimal adjustment for fast and easy placement
- Accurately duplicates anatomy for better fit and performance
What sizes are the preformed SSCs available in
2-7, Pedo and Adult
What are two situations where a UNITEK SSC would be indicated
- May be needed when significant space loss has occurred secondary to interproximal decay
- When caries extends further gingivally than the length of the Ion crown
Which crown type has flat axial surfaces and requires axial contouring
Unitek
Which crown requires shortening and marginal adaptation
Unitek
Which crowns have curved axial design
Pre-countoured ION/ESPE
Which crowns have anatomically defined occlusal surfaces
ION/ESPE
Which crowns require less manipulation to accurately fit a prepared tooth
ION/ESPE
What are the 5 steps for fitting a SSC
- Pick size
- Length of crown
- Marginal adaptation
- Contouring
- Crimping
What measurement is used to help in crown selection
mesio-distal width
How should the crown be placed?
Set lingually and rotate over the buccal slope
Should you have to use a lot of force to put the crown on?
no, it should go into place with little pressure
What is the problem if the crown easily slides over the tooth with no pressure
It is too big
What is the problem is the crown will not seat entirely over the tooth
it is too small
If a crown is too large or a crown before contouring might cause this
Blanching of the tissue
What should you do if a snug fit cannot be obtained
reduce buccal and lingual surfaces slightly
How do you adjust the crown fit if needed
With the crown in place scribe line along buccal and lingual gingival crest
When trimming the crown how much excess should be trimmed off?
Enough so that the margins are 1.0 mm below the scribed line
What instruments decrease the circumference of the crown while creating a fit that is more snug
Contouring pliers
What should you inspect after fitting in terms of the crown margin
- Inspect the crown for exposed tooth structure and open margins
- Crown margin should be 1 mm below gingial crest
What does contouring do to the crown circumference
Reduces
How do you contour the crown
Use contouring pliers to bend inward the gingival third of the crown…..more contouring on buccal and lingual
Why are crown margins crimped
Ensure good cervical marginal adaptation
“Snap” seating
What are the two common crown cements used
Polycarboxlyate
Glass Ionomer
What can you use to have the child help seating the crown
Band seater or bite stick
Three steps to complete crown cementation
- check that crown is comletely seated
- Remove excess cement when tacky
- Use floss to clean interproximal areas
What are the four bullet items for the final check of the crown restoration
- check for interproximal and subgingival cement
- Polish crown surface lightly with pumice
- Check occlusion
- Ignore minor occlusal discrepanciees
Which tooth adjusts itself very quickly
primary molars
What is usually the cause of a crown not seating properly?
A proximal ledge which should be removed with a tapered bur
What is usually the solution to a loss of space?
Rotate the crown slightly mesio-buccally
Use flat beaked pliers to flatten the contact points, this reduces the mesio-distal width
what are the pliers with the little hook like things on the end
Howe pliers
Do crowns interfere with the exfoliation of primary teeth?
No
Crowns are significantly better than restorations if the child is under _____ years of age
5
Crown and alloy are not significantly different if tooth is due to be exfoliated within _____ years
3
What is the main goal behind using SSCs
To keep primary teeth restored until they are ready to exfoliate
What do you want to avoid when deciding to use a crown?
Re-treatment
Things to consider
Patient behavior v. restorative techniques
Longevity/durability of the restoration material
Ability to maintain the restored tooth by appropriate diet and OH
What are the 5 indications for strip crown
- Extensive or multi surface caries
- Congenitally malformed teeth
- Discolored teeth
- Fractured teeth
- Sufficient crown material remains after caries removal to retain resin
What are the materials needed for a strip crown restoration
- Anterior restorative materials
- Celluloid crown forms in various sizes
- Scissors to trim crown form
During a strip crown prep, how are the caries removed?
With a round bur on slow speed to protect the pulp
What are tapered burs used for during a strip crown prep?
Interproximal and incisor reduction
What are the 3 steps to forming the celluloid crown for the strip crown prep
- Crown form trimmed so cervical margin extends slightly below gingival crest
- Height adjusted to match adjacent tooth
- Vent hole placed
What are the 3 steps to prepare the tooth surface for a strip crown
- Pulp protection applied
- Tooth surface etched, washed and dried
- Bonding agent applied and cured
What do you want to avoid when squeezing material into the crown form
creating voids
When the crown is seated, where should the excess composite come out?
Cervical opening and vent holes
Usually you need to cure to a depth of _____ mm
4
Why are they called strip crowns?
Because you strip off the crown form after the composite is cured
What are 4 other types of anterior crowns
SSC
EZ Pedos
SSC w/ Facial cutout and composite (Window)
NuSmile
