Management of Endodontic Failure

Question 1

Aim Endodontics tx?

Answer 1

Prevent/ cure periapical periodontitis

Question 2

How assess outcome of endo?

Answer 2

Has aim been met - absence/ resolution periapical periodontitis

Question 3

Strict sign of success?

Answer 3

No symptoms, no clinical sign disease and no PA radiolucency

Question 4

Loose sign of success?

Answer 4

No symptoms and no clinical sign of disease

Decrease (no increase) size pre-op PA lucency

Question 5

Best way to grade outcome of endo success?

Answer 5

Favourable
Uncertain
Unfavourable

Question 6

What does survival of tooth mean?

Answer 6

Tooth present in arch and is asymptomatic and functional

Question 7

Main 3 factos affect endo success?

Answer 7

1. Pre-op status PA tissue
2. Quality root canal filling
3. Quality coronal restoration

Question 8

What makes success more likely when considered pre-op status PA tissue?

Answer 8

Vital pulp - pulpitis/ necrotic but uninfected

Success = 95%

Question 9

What sign when assessing pre-op status PA tissue would make success less likely?

Answer 9

Periapical periodontitis - PA radiolucency
Because canal heavily infected
Success = 85%

Question 10

Does size of PA radiolucency affect success?

Answer 10

If larger 5mm diameter further reduction chance success

Question 11

What defines a good quality root filling?

Answer 11

Extends within 2mm of apex and is well compact

Question 12

What decrease chance of success when assessing filling?

Answer 12

Overextended/ underextended

Voids in filling

Question 13

What looking for in coronal restoration?

Answer 13

No marginal deficiencies/ defects/ recurrent caries -route for bacteria to re-infect

Question 14

Best coronal restoration provide post-RCT?

Answer 14

Full-coverage

Question 15

Why are full-coverage restoration adv after RCT?

Answer 15

Improve coronal seal

Improve structural durability

Question 16

When should success RCT be assessed?

Answer 16

9-12 months following - clinical and radiographic assessment
Earlier if continued symptomas

Question 17

Should new PA be taken less 9-12 months if pt have symptoms?

Answer 17

Only if suspect further dx e.g root fracture

Question 18

How long should RCT be assessed for?

Answer 18

Depending outcome of review up to 4 years

Question 19

What symptoms should ask pt about when assessing RCT?

Answer 19

Pain, swelling and function

Question 20

Does lack of symptoms = success?

Answer 20

Not always

Question 21

What are other reasons for symptoms if RCT not unfavourable?

Answer 21

Occlusal interferences
Food trapping
Tooth fracture
Neurogenic pain

Question 22

What should be assessed in clinical exam?

Answer 22

Look swelling/ sinus tract
Tenderness palpitation soft tissue
Tenderness percussion of tooth
Presence fractures
Presence caries
Periodontal status - depth/ mobility
Quality restoration

Question 23

What assess post-op radiograph?

Answer 23

Quality filling
Presence/ absence PA lucency
Size PA lucency - compare pre-op
Quality restoration
Caries and perio

Question 24

When would CBCT be indicated to assess RCT?

Answer 24

Persistent pain w/ no sign conventional radiograph

Question 25

What is favourable outcome?

Answer 25

Symtom free Functional tooth Clinically associated tissue health Radiograph - PA tissues healthy

Question 26

When is there an uncertain outcome?

Answer 26

No signs or symptoms BUT Radiograph - PA lucency persist - same size/ reduced within 4 year assessment period

Question 27

When is outcome unfavourable?

Answer 27

Pt symptoms Tooth not functional Clinical sign infection Radiograph: new lucency, increase size lucency, lucency persisted at/after 4 year assessment

Question 28

How does outcome affect further review?

Answer 28

Review 9-12 months Favourable - no further review Uncertain - annual review 4 years Unfavourable = further tx

Question 29

When should indirect restoration be placed?

Answer 29

After resolution clinical signs and symptoms | Don't need wait resolution radiographic lesion

Question 30

4 reasons endo can fail?

Answer 30

Intraradicular infection Extraradicular infection True cyst Foreign body reaction

Question 31

What is intraradicular infection?

Answer 31

Persistant infection due residual microbes left in canal | or microbes re-enter (due coronal leakage/ fracture)

Question 32

What can cause extraradicular infection?

Answer 32

Periapical actinomycosis

Question 33

Why can endo fail due cyst?

Answer 33

Apical cysts are self sustaining and won't heal with satisfactory RCT

Question 34

How assess outcome RCT if you didn't do it?

Answer 34

Hx - where and when performed Ideal if have original diagnosis Did tx initially remove symptoms What technique used - was rubber dam used, hypochlorite etc

Question 35

4 main options if endo failed?

Answer 35

No tx - monitor XLA Endo re-tx Apical surgery

Question 36

What should pt be advised if endo fail and have decided no further tx?

Answer 36

Tooth will require regular review To return if signs/ symptoms develop Acute flare up may occur

Question 37

When are XLA considered after failure RCT?

Answer 37

Pt doesn't wish have further tx Tooth restorability doubtful Non-functional tooth w/ no strategic value Untreatable disease - root fracture/ advanced bone loss

Question 38

What is tx of choice if have post-tx disease and pt keen to save tooth?

Answer 38

Endo re-tx

Question 39

What must a tooth be to consider re-tx?

Answer 39

Restorable

Question 40

Is success of re-tx good?

Answer 40

Success = 80% | Success normal RCT = 83%

Question 41

What should pt be advised of prior re-RCT?

Answer 41

Tooth may be deemed unrestorable - fracture/ gross caries | Complex w/ associated risks - perforation, unable instrument canal

Question 42

When can surgical endo be carried out?

Answer 42

Not possible to carry out re-rct

Question 43

Indications surgical endo (re-tx)?

Answer 43

Re-RCT would be unfavourable Obstructions in canal can't be removed/ negotiated Posts - risk fracture if removed Perforation - need surgical repair Investigative procedure - biopsy/ confirmation fracture True cyst

Question 44

What does endo-re-tx comprise of?

Answer 44

Removing content canal following by disinfection and cleaning Can include repair perforation

Question 45

What are ways to remove GP?

Answer 45

GG bur followed hand file (K and H files) Re-tx rotary NiTi Solvent technique

Question 46

How are GG and hand files used in re-tx?

Answer 46

GG removes coronal GP Hand files remove apical GP Use tactile sensation of rubbery GP

Question 47

Why use hedsrom files for re-tx?

Answer 47

Grip GP as it engages in the cutting flutes

Question 48

Adv using rotary NiTi re-tx files?

Answer 48

More resistant fracture and dislodge GP coronal direction

Question 49

Examples of solvent?

Answer 49

Chloroform, eucalyptus and orange oil

Question 50

Ideal time to use solvent?

Answer 50

Following bulk removal

Question 51

How can endo posts be removed?

Answer 51

Use ultrasonic - break cement lute Using fine forceps Post removal kits

Question 52

Stage of removing endo post?

Answer 52

Remove crown and core material - leave post | Loosen post

Question 53

How remove threaded post?

Answer 53

Can often be unscrewed

Question 54

What technique can be helpful to remove therma-fil carriers?

Answer 54

Using braiding technique - braid.2 hand files around carrier

Question 55

Issue with silver points?

Answer 55

Corrode over time - can disintegrate during removal

Question 56

What changes success of removal fractured instrument?

Answer 56

``` Where instrument fractures What type instrument it is How long fragment is Accessibility Ability bypass if can't be removed ```

Question 57

How remove fractured instrument?

Answer 57

Good access and vision - microscope | Use ultrasonic/ modified GG

Question 58

What assess when perforation made?

Answer 58

Size Location Condition remaining tooth

Question 59

Types of perforation?

Answer 59

Internal and external

Question 60

Choice of material for repair perforation?

Answer 60

MTA | Biodentine

Question 61

What are pt options in general practice for re-tx?

Answer 61

Refer to dentist - specialist/specialist interest - private | Refer hospital - not all will accept