Week 10- Solutions for common Endodontic Problems

Question 1

What are some endodontic problems?

Answer 1

• Access to the pulp chamber
• Location of fine and calcified canals
• Problems with cleaning, shaping and obturation
• Problems with re-treatment
• Problems with post-endodontic treatment
• Endodontic emergencies
• Root-Resorptions
• Perio-Endo Lesions
• Perforation

Question 2

What should be done before accessing the pulp chamber?

Answer 2

Remove caries and restore tooth with stable restoration (not GIC)

Question 3

What is the reason for doing a stable CR filling before endo tx?

Answer 3

• If GIC is used it can wash out and the reference points can be lost (would need to start again)
• Helps with rubber dam placement

Question 4

What are tips for accessing pulp chamber?

Answer 4

• Know anatomy and where to find canal entrances
• Have radiograph visible
• If you need to access through a crown, don’t trust visible anatomy- trust the radiograph. If necessary, get another radiograph with cone shift.
• Get straight line access
• Have loupe/microscope with high magnification
• Clean floor of pulp chamber

Question 5

What are tips for locating fine and calcified canals?

Answer 5

• Use small instruments #8, #10
• Use special pathfinder instruments (stiffer- better tactile feedback)
• Use sonotrodes for digging
• Rinse with lots of hypochlorite
• move files slowly
• Clean files frequently
• If file is bent, replace it.
• If canal is finally not accessible, leave it and fill accessible ones. Then, reconsider case.

Question 6

What are tips for eliminating problems with shaping?

Answer 6

• For EAL, recheck lengths after initial shaping
• If unsure, reconfirm with silver points
• Always have stable and reproducible reference points
• Apex and reference point need to be visible on IOPA
• Shape canal entrances (gates glidden or circumferential hand-filing with H file)
• Do not over or under shape

Question 7

How do you prevent ledge formation during cleaning and shaping?

Answer 7

• Pre-bend steel files
• Use H files
• Use NiTi rotary systems
• Rinse

Question 8

How can you prevent file fractures with cleaning and shaping?

Answer 8

• Do not push files- lubricate
• Use only for short time
• If file does not want to work, skip to a smaller one

Question 9

What can overshaping cause?

Answer 9

Strip perforation

Question 10

What is the issue with undershaping?

Answer 10

Cleaning and obturation is difficult

Question 11

What is the general rule for rinsing canals?

Answer 11

• 5ml per canal (for molar 3 syringes)
• The cleaning solution needs time to clean: 10-20 mins overall cleaning time
• Preheated solutions and ultrasonic activation are recommended

Question 12

What are problems with obturation

Answer 12

• Fitting master cone can be difficult
• Cone pulling out during condensation

Question 13

What should you do if the master cone is too short vs too long from the apex?

Answer 13

• Too short: smaller cone or reshape
• Too long: cut the tip
• No tug back: cut the tip
• Always check with x-ray (cone should be at exact reference point)

Question 14

Why is tug back required?

Answer 14

Ensures good master cone fit and better control during condensation

Question 15

What does it mean if master cone pulls out during condensation

Answer 15

• Tug back not sufficient (no friction)
• Condensation force too small

Question 16

How can we avoid problems with retreatment?

Answer 16

• Use H files >#20
• Frequently check file and replace if damaged.
• Don’t use chloroform or NiTi rotary files

Question 17

When should posts be placed for RCT?

Answer 17

• If no problems are expected, immediately place a post
• If problems are expected wait at least 1-2 weeks.

Question 18

How/when should RCT teeth be restored following obturation?

Answer 18

• Apply stable adhesive restoration directly after obturation
• If a crown is required, do it ASAP (2-4 weeks)

Question 19

What are key factors for treating endo emergencies?

Answer 19

• Sound diagnosis and sufficient LA
• If need to start RCT, do it directly and do it well
• NSAID’s are generally not sufficient for pulpitis
• No antibiotics are required unless special indication.

Question 20

How should root resorptions be managed?

Answer 20

• Remove cause (infection?) and resorption has a chance to stop
• No lost tissue can redevelop
• Inform pt about limited success probability

Question 21

How should lateral root-resorptions be managed?

Answer 21

• Remove cause and resorption has chance to stop
• Take IOPA with horizontal tube shift to rule out internal resorption
• Inform pt about limited success probability.
• Use ledermix

Question 22

How should perio-endo lesions be managed?

Answer 22

• Confirm diagnosis
• RCT and initial perio tx
• Reconsider case after 3-6 months
• Basic idea: both inside and outside must be cleaned sufficiently
• Endo first bc healing of perio tissues will not be possible until infection/inflammation is removed from the root canal system. More predicatble outcome if endo done first.

Question 23

How should perforations be managed?

Answer 23

• Close perforation with MTA after general cleaning and shaping
• Microscope highly beneficial

Question 24

What material is used if the perforation is above bone level vs below?

Answer 24

Below bone or in furcation: MTA

Above bone level: GIC

Question 25

Can you fix perforations with Ca(OH)2?

Answer 25

No, because it doesn’t set

Question 26

If high bacterial load, how long should dressing be placed?

Answer 26

Ca(OH)2 for time between 1-4 weeks