Y3 L8 Retreatment and surgery

Question 1

What is the sucess rate of primary root canal treatment?

Answer 1

86% to 98%

Question 2

What are the 3 RCT outcomes after 1 year as defined by the ESE?

Answer 2

• Success
• Uncertain
• Unfavourable

Question 3

How does the ESE define success?

Answer 3

• Patient is asymptomatic and can funciton equally well on both sides
• The periodontium should be healthy, including a normal attachment apparatus
• Radiographs should demonstrate healing or progressive bone fill overtime
• Principle of restorative excellence should be satisfied

Question 4

How does the ESE define an uncertain outcome?

Answer 4

• Radiographically, the lsion has remained the same size or only diminished in size
• If this occurs, assess the lesion each year until it has resolved or for a minimum period of 4 years
• If it persists after 4 years, the tooth is usually considered to be associated with post-treatment disease

Question 5

How does the ESE define an unfavourable outcome?

Answer 5

• Tooth is associated with signs and symptoms of infection
• Radiographically, the PDL space may be widened, lamina dura lost or a visible lesion has appeared, or pre-existing lesion increased in size
• Lesion has remained the same size or only diminished in size during the 4 year assessment period
• Signs of continuing root resorption

Question 6

What are the tx options for persistent disease following RCT?

Answer 6

• Extraction
• No tx (risks of pain, acute abscess formation and lesion increasing in size which will reduce success rates of retreatment)
• Re-treatment: non surgically or surgically

Question 7

How is post treatment disease defined?

Answer 7

Presence of a post-treatment inflammatory periradicular lesion (i.e. apical periodontitis) on a root filled tooth where the lesion can no longer be assumed to be undergoing healing.

Question 8

What are the indicators of endodontic treatment failure?

Answer 8

Clinical:
- Pain/discomfort
- Infection and swelling
- Sinus tract

Radiographic:
- Widened PDL space
- Loss of lamina dura
- New periapical lesion or pre-existing lesion has increased in size
- Signs of continuing root resorption

Question 9

What are the possible reasons for non-healing apical periodontitis?

Answer 9

• Poor technique: no rubber dam, inability to instrument all of the root canal, inadequate restoration leading to leakage, poor disinfection, poor obturation
• Missed canals
• Complex anatomy
• Extra-radicular infection
• True cysts
• Foreign body reaction
• Iatrogenic errors

Question 10

What is the most common cause of endo tx failure?

Answer 10

An inadequate RCT.

Question 11

What are the microbial and non-microbial aetiological causes of post treatment disease?

Answer 11

Microbial: intra- or extra-radicular infection
Non-microbial: cysts

Question 12

Describe intra-radicular infection as a cause of post treatment disease.

Answer 12

Bacterial infection within the root canal system
- Most common cause of post-treatment disease
- Causes include inadequate cleaning and shaping, obturation with voids or short of apex, poor corontal seal
- Bacteria can recolonise and cause infection, or enter through poor restoration
- Causes apical periodontitis

Question 13

Desribe extra-radicular infection as a cause of post treatment disease.

Answer 13

Infection outside of the root canal system
- Occurs if bacteria invade the peri-radicular tissues.
- Actinomyces israelii is one bacterial species commonly associated with this type of infection

Question 14

Describe cysts as a reason for post treatment disease.

Answer 14

• Very rarely, a periapical cyst can be the cause of post-treatment failure.
• Can be very challenging to diagnose.
• Cysts may not respond to non-surgical root canal treatment.
• Treatment: surgical removal of lesion and microscopic testing

Question 15

What are the indications for non-surgical retreatment?

Answer 15

• Where possible, non-surgical treatment is always preferred over surgical
• Teeth with inadequate root canal filling with radiological findings of developing or persisting apical periodontitis and/or symptoms
• Teeth with inadequate root canal filling when the coronal restoration requires replacement or the coronal dental tissue is to be bleached

Question 16

How is GP removed?

Answer 16

• Good vision, magnification with loupes/microscope
• Gates Glidden burs to remove coronal portion of GP
• D series rotary ProTaper files
• Hedstrom files
• Use solvents to remove GP in difficult cases where files alone are not sufficient

Question 17

How should you obturate a tooth with an open apex?

Answer 17

• MTA plug
• Warm GP

Question 18

What are silver points?

Answer 18

• Historic
• Poor sealing ability, subject to corrosion
• Silver point can be removed with Steiglitz forceps and retreated with GP

Question 19

How are crown posts removed?

Answer 19

Use ultrasonic and a post removal kit.

Question 20

What is the risk with post crowns?

Answer 20

Post crowns are more likely to experience a vertical root fracture due to the high stress placed on the root, the only treatment option is extraction.

Question 21

What are the indications for surgical retreatment (ESE)?

Answer 21

Question 22

What are the indications for surgical retreatment (RCS)?

Answer 22

1. Periradicular disease associated with a tooth where iatrogenic or developmental anomalies prevent non-surgical root canal treatment being undertaken
2. Periradicular disease in a root-filled tooth where non-surgical root canal retreatment cannot be undertaken or has failed, or when it may be detrimental to the retention of the tooth (eg obliterated root canals, teeth with full coverage restorations where conventional access may jeopardise the underlying
   core, the presence of a post whose removal may carry a high risk of root fracture).
3. Where a biopsy of periradicular tissue is required.
4. Where visualisation of the periradicular tissues and tooth root is required when perforation or root fracture is suspected.
5. Where it may not be expedient to undertake prolonged nonsurgical root canal retreatment because of patient considerations.

Question 23

Describe the steps of apical surgery.

Answer 23

1) Local anaesthesia
2) Raise flap to visualise lesion
3) Perform osteotomy to gain better access and vision to the lesion: use a rear-exhausting surgical turbine with sterile coolant, sharp burs and a shaving action, use micro mirrors due to small structures
4) Curette lesion and send to pathology department
5) Root resection
6) Root end prepared with ultrasonics, 3mm of GP removed
7) Root end is filled with MTA
8) Wound debrided, flap closed using sutures