impression faults

Question 1

What are 5 reasons for the incomplete reproduction of preparation margins?

Answer 1

1. insufficient retraction
2. blood and saliva contamination
3. impaired flow ability due to exceeding working time
4. inadequate coverage of the area with light body
5. impression material has a low tear resistance

Question 2

6 causes of voids on the margin:

Answer 2

1. blood and saliva contamination
2. improper syringe technique
3. working time exceeded (impaired flow ability)
4. air bubbles in syringes
5. tray not seated properly
6. stored at a higher temperature

Question 3

6 causes of voids on the margin:

Answer 3

1. blood and saliva contamination
2. improper syringe technique
3. working time exceeded (impaired flow ability)
4. air bubbles in syringes
5. tray not seated properly
6. stored at a higher temperature

Question 4

Causes of tearing at the margin:

Answer 4

1. insufficient retraction
2. inadequately mixed materials
3. premature removal of the impression
4. imp material has low tear resistance
5. expired impression material

Question 5

Causes of distortions in the final impression:

Answer 5

1. working time exceeded
2. lack of support / stabilisation of the tray by the operator
3. distortions during impression removal
4. inappropriate combination of the tray and impression material