Is it rigid or elastic?
Rigid
Is it reversible or irreversible?
Irreversible
Its set due to____
Chemical change
Count its uses.
- as a cement l, to fill the spaces between the gingiva tissue and teeth since it protects agains bacterial infection)
- Temporary Filling(for hollow teeth to spread the compaction between upper and lower teeth force)
- Root canal filling(to prevent and/or even cure them)
- Is a part of surgical pack
- Bite registration paste
- Temporary relining material(placed on the bottom of the teeth to shape the gingival that holds the teeth to make the dentures are more comfortable for the patient)
- For final impression
Why do they use Zinc oxide eugenol for Bitting registration paste?
Becuase it has a short setting time
Why do they put plasticisers on zinc oxide eugenol when they use it for Bite registration?
To prevent it from sticking to the tissue
In what form do they provide zinc oxide eugenol?
Two paste tubes:
1)base(White zinc oxide)
2)catalyst(eugenol)
How many types of zinc oxide eugenol are there?
Type:
I)hard
II)Soft
How thick is the paste?
1mm
Why should the amount of the two pastes be the same?
To not change the setting time
How long should the mixing be?
30-40sec
Define working time
Its the amoint of time needed to mix the pastes, pour it in the tray and seat the tray in the mouth of the patient
What do you use to mix the two pastes?
A mixing pad and a spatula
The initial setting time of Type I is ___min, and the final setting time for Type II is ___ while the initial setting time for type II is and the final setting time fornType I is ____
3-6, 15, 3-6, 10
What type of tray is used with zinc oxide eugenol?
Special tray(they are trays made from the primary impressions of the patient)
How to increase the setting time of zinc oxide eugenol?
- Cooling the pad and spatula
- Using oils like olive oil
How to decrease the setting time of zinc oxide eugenol?
- Put in small amounts of Zinc acertate
- Put it additive accelerators
- Small drops of water
What are the properties of zinc oxide eugenol?
- Consistency and flow
- Dimensional tolerance: it shrinks<0.1% during hardening
- Detailed and accurate
- Causes irritating tissue and sometimes burning sensation in the mouth
Advantages of zinc oxide eugenol
- Dimensional stability
- Accuracy
- Can be modified
- Easy to manipulate to fit your case, like its setting time(by changing the amounts of pastes)
- Long working type
Disadvantages of zinc oxide eugenol
- Burning sensation becuase of eugenol
- Sticks to the skin
- Its rigid so it breaks in undercuts