6. Obturation

Question 1

The smear layer is formed during canal preparation. What is it and what problems does it cause?

Answer 1

The smear layer is organic pulpal material and inorganic dentinal debris. It packs into dentinal tubules (1-5um).
If left in the canal it can cause bacterial contamination, substrate & interferes with disinfection. It can also prevent sealer penetration.

Question 2

How is the smear layer removed?

Answer 2

17% EDTA or 10% citric acid

Question 3

What is the function of a sealer?

Answer 3

Seals space between dentinal wall and obturating material.
Fills voids and irregularities in canals, lateral canals and space between GP points.
Lubricates during obturation.

Question 4

What are the three methods for placing sealers?

Answer 4

Master cone
Files
Ultrasonics

Question 5

What are the four methods of GP obturation?

Answer 5

Cold lateral compaction
Warm vertical compaction
Continuous wave compaction
Carrier based obturation

Question 6

What are the pros and cons of cold lateral compaction?

Answer 6

Can be used in most clinical situations.
Good length control.
Does not allow good adaptation to canal irregularities.

Question 7

What are the five thermal techniques for GP obturation?

Answer 7

Warm vertical compaction
Warm lateral compaction
Thermoplastic injection techniques
Continuous wave compaction
Carrier-based techniques

Question 8

What is the problem with overfilling the canals?

Answer 8

Decreases chance of apical regeneration

Question 9

What factors affect the timing of obturation?

Answer 9

Signs & symptoms
Pulp status
Periapical status
Difficulty
Patient management