Cementation Flashcards
It is essential that both the casting and the tooth preparation are _____ and ____ prior to the cementation procedure.
Clean
Dry
What must be maintained during the entire set time of the cement?
A dry field
What are the four common types of luting agents?
- Zinc Phosphate Cement
- Zinc Polycarboxylate Cement
- Glass Ionomer Cement
- Composite Resin Cement
What is the main weakness associated with Zinc Phosphate?
It may cause moderate pulp irritation
What are four strengths associated with Zinc Phosphate?
- Adequate ______
- High ______
- Reasonable _____ ______
- Easy _____ ___ ______
- Strength
- Solubility
- working time (five mins)
- removal of excess
Mixing of Zinc Phosphate requires what materials and equipment?
Powder: Zinc Oxide
Liquid: Phosphoric Acid
Glass Slab for Mixing
What is the main difference between Zinc Phosphate and Zinc Polycarboxylate?
Zinc Phosphate may cause moderate pulp irritation, Zinc Polycarboxylate will NOT
Which has a shorter working time, Zinc Polycarboxylate or Zinc Phosphate?
Zinc Polycarboxylate
Which is easier when attempting to remove excess material, Zinc Phosphate or Zinc Polycarboxylate?
Zinc Phosphate
Zinc Polycarboxylate is intended for use in cementation of _______ because its rapid increase in film thickness may impede proper seating of a casting.
single metal units in low stress areas on sensitive teeth
What is the main disadvantage and main advantage to using Glass Ionomer Cement?
Disadvantage: susceptible to moisture contamination
Advantage: release of Fluoride
Glass Ionomer has a higher ______ than both Zinc Polycarboxylate and Zinc Phosphate.
Compressive Strength
In what two forms is Glass Ionomer available?
- Hand-Mixed (powder + liquid)
2. Capsulated
Composite Resin Cements are not suitable for use on ____.
Gold Castings
Resin Composite Cement bonds _____ to resin composite restorative materials and ______ porcelain.
Chemically
Silanated
Composite resins will bond ____ to resin composite restorative materials and will bond ______ to sandblasted metal alloys.
Chemically
Micromechanically
Which cement allows for shade-matching?
Composite Resin
The newest variety of cements is “resin-modified glass ionomer” which provides high _______, low _____, and _____ release.
Strength
Solubility
Fluoride
Compare the strength of Resin-Modified Glass Ionomer to that of other cements.
- **stronger than: zinc phosphate, zinc polycarboxylate, and some glass ionomers
- **weaker than composite resin
Resin modified Glass Ionomer is ______ soluble than glass ionomer but has similar adhesion properties and fluoride release.
Less
BOARDS: On what kind of surface should cements be mixed?
On a thick, COOL, glass slab
BOARDS: How should the glass slab, used for mixing cement, be cooled?
Run the slab under cold tap water for 15 minutes, then dry completely
BOARDS: Why should the glass slab be cooled prior to mixing the cement?
The cool surface will increase the working time of the cement by slowing the exothermic chemical reaction
What is the powder to liquid ratio for cements?
Powder: 1 inch diameter mound
Liquid: 8 drops per crown
What are the advantages and disadvantages to an increased powder to liquid ratio when preparing cement?
Advantages: Improved Strength, reduced solubility
Disadvantage: Increased viscosity
Into how many increments should cement powder be divided?
8
What is the proper mixing technique for cement?
On a cool glass slab, divide the 1 inch mound of powder into 8 increments, drop 8 drops of liquid per crown onto the opposite end of the slab, incorporate one increment of powder into the liquid, mix for 10 seconds over a WIDE area of the glass, continue adding increments to the mix, evaluate cement thickness after half of the increments have been added
What is the proper cement thickness?
Raise the spatula 1 inch above the glass slab and evaluate over 1-2 second time lapse. Ensure that there is a Thin band that forms
What is the improper cement thickness?
Raise the spatula 1 inch about the glass slab and evaluate over 1-2 second time lapse. If a thick, wide band forms it is incorrect.
True or False: If the cement mix is too thick, continue adding drops of liquid until reaching the desired viscosity.
FALSE: if it is too thick, discard and begin again. Adding liquid to the mix would interfere with the setting reaction and weaken the cement
BOARDS: When the proper consistency of cement is reached, cover the _______ of the casting.
Axial Walls
do not FILL the casting with cement
BOARDS: True or False: When applying cement, the axial walls of the casting and the prepared tooth should be lightly coated.
False: NEVER COAT the prepared tooth!
______ a casting to seat has been shown to be ineffective and is liable to cause tooth fracture.
Malleting (forcing)
BOARDS: Should you etch a tooth before cementation?
No, you want to protect the prepared tooth from leaking chemicals into microtubules. May even want to use varnish on the prep
When seating a casting, place the casting on the prepared tooth and press firmly with your finger in the direction of _______.
The path of insertion
Utilize a _______ motion when seating a casting.
Rocking
buccal-lingual rock…. the roll mesial-distal
What should be done if the casting cannot be completely seated?
REMOVE IT IMMEDIATELY
If the cement has set sufficiently, but the casting is not properly aligned, how will the casting be removed?
The only way is to CUT it off and START OVER at your expense
What are some causes of incomplete seating?
- Luting agent too thick
- insufficient seating force
- Binding occured between axial walls of the prep and casting
In a clinical setting, if the set time is 10 mins, firm pressure from biting on a cotton roll must be applied for ____mins. Moderate force is then needed for an additional ____mins.
4
6
Remove excess cement with a(n) _______ moving _____ to the margins.
Explorer
Parallel
When evaluating a cemented casting, there should be proper _____ ________, proper _________, and absence of ______.
Margin adaptation
Contours
Rocking-movement
