CSA endo labs week 3

Question 1

What are problems with RCT?

Answer 1

•Unable to gain access to
o	pulp chamber 
o	To the canal 
•Unable to reach apex
•Loss of working length 
•Breakages

Question 2

What happens when can’t access pulp chamber?

Answer 2

• Check preop radiograph – look for depth & direction
• Check direction of drilling regarding anatomy & root angulation
• another radiograph if in doubt

Question 3

What to check in Radiograph?

Answer 3

• pulp chamber, size & position
• Canal: location, size & curvature
• Obstructions
• Likely working length
• Look for accessory canals – particularly in maxilla

Question 4

What happens when can’t access canal?

Answer 4

• Look for colour of dentine at canal orifice – darker
• DG16 probe often get past obstructions
• NaOCl in pulp chamber – look for bubbles at orifice
• small file, lubricant

Question 5

What happens when can’t reach apex?

Answer 5

• use a smaller file
• Lubricate & make canal wet
• Pre – curving file tip ( get around bend/corner)
• Use watch winding technique
• Heavy apically directed pressure won’t help
• Use file & lubricant, not muscles

Question 6

What does heavy apically directed pressure lead to?

Answer 6

breakages and ledges

Question 7

When does loss of working length occur?

Answer 7

• Occurs during or after shaping
• Usually occurs due to:
o Accumulation of debris apical to file
o Creation of ledge/dent with file tip

Question 8

When do breakages occur ?

Answer 8

• Over use of instruments
• Heavy handed use of small instruments
• Instrumenting tightly curved canals
• Poor lubrication
• heavy apically – directed pressure

Question 9

When to discard files after use?

Answer 9

o Unwinding flutes

o Kinks

Question 10

What to do with breakages ?

Answer 10

• Verify breakages
• Own up to patient
• Take a radiograph & identify fragment
• Discuss options w/ patient
• Change treatment plan

Question 11

How to verify breakage ?

Answer 11

Look at instrument and see it’s not same length as put in

Question 12

What are solutions to breakages ?

Answer 12

•	Engage fragment & retrieve it:
•	Work past/ 
- Accept it ,Obturate up to fragment 
•	Apicectomy 
•	Extract tooth

Question 13

When is apicectomy ued?

Answer 13

o Last resort if fragment too large/bacteria present there

o surgery to expose the root

Question 14

How to engage fragment and retrieve ?

Answer 14

o Use another file – try engage file to pull it out

o Ultrasonic scaler – shakes fragment loose

Question 15

What if can’t make prgress with breakage ?

Answer 15

• Own up to mistake

* Discuss options with patient

Question 16

What solution with unable to progress with problem

Answer 16

• Refer to specialist
• Expect sub-optimal result
• Extract tooth