Obturation

Question 1

when do we obturate?

Answer 1

• After thorough disinfection and shaping of the canal
• In the absence of any signs, symptoms of periradicular infection (Swelling, pain, discharging sinus)
• When we are able to achieve a dry canal

Question 2

list the aims of obturation

Answer 2

• To fill the entire pulp space
• A 3-dimensional hermetic seal
• To provide a barrier to reinfection from oral micro-organisms
• To provide a barrier to nutrient supply from peri-radicular tissue fluids

Question 3

What are the ideal properties of a root canal filling material (obturating material)?

Answer 3

• Dimensionally stable
• No shrinkage / expansion
• insoluble
• Easy to place
• Easy to remove
• Biocompatible
• Radio-opaque
• Anti-bacterial
• Long working-time

Question 4

what are the instruments and material used for obturating?

Answer 4

Paper points
Gutta percha points
Root canal sealer (Tubliseal (ZnOE))
Finger spreaders

Question 5

what are paper points used for in obturation?

Answer 5

to dry canals before we obturate

Question 6

how do we know which size of paper points to use to dry the canals?

Answer 6

matching the size to the size used for shaping

Question 7

what material is used for root canal sealer in obturation?

Answer 7

zinc oxide euginol

Question 8

what do finger spreaders correspond with in terms of size?

Answer 8

accessory points

(A, B, C, D)

Question 9

obturation - list the steps of cold lateral compaction

Answer 9

1. Choose a GP point that is matched to your finishing file (F1/F2/F3)
2. Create a notch at the working Length and grip in lockable Tweezers at the working length
3. Check it reaches the Working length

(up to this point canal should be wet from irrigation material used - this helps GP to reach length)

4. Once you’re happy with step 3 (it goes to length), check for tug-back – slight resistance to withdrawal from the canal
5. take X-ray to see if the GP has achieved the working length
6. Dry the canal with paper points
7. Coat canal walls with a thin film of sealer paste
8. Seat the master point in the canal ensuring it still reaches the working length
9. Select an appropriately sized finger spreader and set the stop to be 1 - 3mm short of the working length
10. Hold it in place applying a light apical pressure for at least 15 seconds to allow the GP to adapt, twist and remove
11. Fill the resulting space with a GP point matched to the spreader used and coated in sealer
12. Repeat until the whole canal is filled until a spreader no longer goes further than level with the CEJ
13. Take a final radiograph to check for quality of root filing
14. Using a heated plugger, remove excess GP and compact the coronal 1/3 of the canal
15. Line the access cavity with RMGIC (Fuji Liner) covering the amputated GP
16. Finally - restore the access cavity

Question 10

obturation - if the GP isn’t going down sully into the length of the canal, what could this be caused by?

Answer 10

maybe curved canal - may require the point to bend round the corners and adapt to shape of canal

Question 11

During obturation, why is tug-back so important when placing GP into the canal to see if it is the right size?

Answer 11

means that the GP will not be pulled during obturation

Question 12

obturation - what is meant by the master-point X-ray?

Answer 12

Once we irrigate the canal, try our GP point in, achieve tug-back, we then take an X-ray to ensure that point is reaching the working length

Question 13

what is a mid-fill radioghraph?

Answer 13

we apply sealer to the master GP point, and do same thing as with master-point X-ray but just with sealer

Question 14

obturation - why is it important to work quickly when placing accessory points after opening space up with finger spreader?

Answer 14

as space will be lost due to elastic recoil of the GP already placed

Question 15

obturation - what material should we ideally restore the access cavity with?

Answer 15

composite

Question 16

list the most common problems with obturation

Answer 16

• Unable to get the canal dry
• GP point gets bent in the canal
• No tug-back achieved
• GP points come out with the spreader
• Sealer paste sets too quickly
• Excessive pressure can cause root fracture
• Final radiograph shows:
  
  • Root filling to be short
  • Root filling to be through the apex
  • Voids in the canal

Question 17

obturation - what could we have done wrong if the GP is coming out with the spreader?

Answer 17

didnt have enough tug-back
not enough sealant