**Retraction Cord Flashcards
True or False: When packing cord for a restoration, the cord needs to be placed around the entire tooth.
False
How much healthy tooth structure should be exposed in the impression for the lab to fabricate a successful crown?
the prep line and 0.5-1mm of additional healthy tooth structure
What is the smallest size of retraction cord?
000
What type of retraction cord is preferred, and why?
braided cord is preferred over knitted because knitted can fray easier
Who chooses the size of the retraction cord to be placed?
the operator
What additive promotes contraction of the tissues?
astringent
What additive constricts the blood flow by causing coagulation?
hemostatic
True or False: Cord cannot be layered with multiple pieces.
False
When placing two pieces of cord, what size should be packed first?
the smaller size
How should cord be packed?
-clockwise
-counterclockwise
clockwise
What area of the prep should you begin packing the cord?
at the proximal areas
When the tissue is rebounding and the cord is difficult to place, what type of pressure should you use with the cord packing instrument to aid in easier packing?
Do not press harder; use firm but gentle pressure for a longer time period
How long should the cord remain in place prior to removal?
5-6 minutes
When removing the cord, should you keep the cord dry or moisten the cord?
moisten
How long after the cord is removed will the tissue remain retracted?
30 seconds
What is cordless retraction paste made out of?
diatomaceous clay and aluminum chloride
Aside from placing a rubber dam, what is the most effective and most common method to achieve ginigval retraction?
packing cord
What chemical has been added to impregnated cord that is no longer recommended to be used?
racemic epinephrine
Does retraction cord shrink or expand when wet?
expand
List some common chemical additives to retraction cord.
-racemic epinephrine(contraindicated)
-ferric sulfate
-aluminum potassium sulfate
-aluminum sulfate
How long after the retraction cord has been removed can the chemical additives in the cord continue to have beneficial effect on the tissue?
20 minutes
For a crown prep, what is the average length of cord needed to completely surround the entire tooth?
1-1.5 inches
If retraction cord needs to be overlapped, what area is best indicated to place the second piece?
the proximal area
Why is it commonly contraindicated to overlap cord around the buccal/facial or lingual margins of the tooth?
the gingiva here is tighter and thinner and can cause gapping that will distort the accuracy of the impression