Success/ failure in endodontic treatment Flashcards
Describe this radiograph
Poor root filling
Uncercondesned
Overfilled
Large lesion present on the tooth
Post treatment disease or fialure
Describe this radiograph after 3 weeks other radiograph
Treated using biological
Root canal decontaminates
Dress with calcium hydroxides and obturated to the correct length
Good healing
3 weeks post previous radiography
Extraordinary healing - good balanced root canal treatment
No voids
Patient is comfortable
Technical success
Biological success
describe this radiograph
Good root filling
Well condensed
Good white stripes
Lots of irrigation
Describe this radiograph
6 month review
Lesion shrunk down in size
Not completely gone
Both technical and biological success
No swelling or sinus
Describe this radiograph
Radiograph with complex lower first molar
Describe this radiograph
Technical success
Just filled it
Single visit treatment
6-12 months if lesion present
Successful outcome
Describe this radiograph
Thencial approach
Challenging approach
Double
Well condensed well tapered
Distal buccal root
All goen to plan
Considerable manual dynamic
Root canal decontaminated
Small minimal access cavity
Patient should not be experiencing no symptoms
problem
Root filling unacceptable in terms of apical extent
Fill hallways down the root- means prepared halfway down the tooth
Preparation of root canal treatment has been insufficient
Denser fill- less chance of leakage
Filled short
Lack of cleaning that caused the problem\
problem
Exturde - foreign body reaction= failure
Reason this has happened - due to faulted preparation
No taper
No resistance or retention
Apex not kept as smalls s reasonably possible
Careful in preparation so it’s easier to obturate
Problem
Extrusion of gutta percha
Heat up gutta percha = no retention or resistance - easy to extrude
Foreign body extruded into tissues
Equally not symptomatic
Healing in apex
Extrude materials = lower success rate
Problem
Not well condensed filling
Look at preparation
Immature tooth = trauma
Root development not completed
Wide canal = obturate
Somebody selected correct obturation technique
Cold lateral impaction = difficult to create taper
Can’t leave the tooth like that
Consequence of leaving -
Need to address
Medical legally asking for trouble
Obturation needs to be correct as it should be
Problem
Closer
Shorter in mesiobuccal root
Distal buccal root
Shorter than radiographic apex
Problem?
No voids in it
Still too heavily prepared
Not prepare teeth heavily
Likely to fracture
🕐 How long after root canal treatment (RCT) should we assess success?
At least 1 year, then periodically if needed. Some healing (like radiographic changes) can take up to 4 years. ⏳
✅ What are clinical signs of a successful RCT?
❌ No pain
❌ No swelling
❌ No sinus tract
✅ Full function restored
✅ No tenderness
✅ Tooth feels and looks normal
🦷 What radiographic feature indicates healing?
A normal periodontal ligament (PDL) space around the root. However, full PDL regeneration may take longer than 1 year.
📉 What if a lesion shrinks but doesn’t disappear after RCT?
Outcome is uncertain. Keep monitoring until resolved — minimum 4 years. After that, it may be considered a post-treatment disease.
🧍♀️ From a patient’s perspective, when is RCT “successful”?
Lesion is getting smaller
Tooth feels normal and pain-free
They can eat/function without issues
📚 Who sets formal criteria for endodontic outcomes?
The European Society of Endodontology (ESE), based on Strindberg’s 1956 strict criteria and Friedman’s loose criteria.
💡 What are ESE’s strict success criteria?
✅ Normal PDL space
✅ No symptoms
✅ Full function
✅ Radiographic healing
❌ No periapical radiolucency
🧪 What are Friedman’s loose criteria (Toronto Study)?
Tooth is functional
Asymptomatic
Radiographic lesion is shrinking
Allows for healing to take up to 4 years
🧮 What is the difference between “success” and “survival”?
Success = clinical + radiographic healing
Survival = tooth is still present and functional, regardless of radiographs
📊 What are average success rates of RCT?
✅ 90–95% for vital teeth
✅ 90% for retreatments if anatomy is respected
✅ 90% for microsurgical techniques
✅ 97% survival over 8 years!
🧫 What defines a good biological approach in RCT?
Proper disinfection
Calcium hydroxide intracanal dressing
Obturated to correct working length
✅ Healing occurs
🔧 What defines a good technical approach in RCT?
All canals are located & cleaned
No voids, proper taper
Obturated within 0–2mm of apex
Avoids overfill, blockages, ledges, or fractures
👀 What do “white stripes” on a radiograph suggest?
Densely filled canals — indicating excellent obturation quality 📸✨
❗ What can cause biological failure even with good technique?
Persistent infection
Missed canals
Poor coronal seal
Contaminated field
Wide canals not obturated properly
❌ What are common iatrogenic errors in RCT? (6)
Instrument fractures
Ledges from forcing files
Missed canals
Short fill or overfill
Lack of taper
Incorrect working length
🔥 What are risks of overfilling the canal?
Causes foreign body reaction
Delays healing
Leads to persistent inflammation
Especially bad when heated gutta-percha lacks apical resistance
🧱 Why is proper canal taper important?
Ensures proper retention, resistance form, and sealing of obturation.
🧪 What final irrigant helps improve success?
EDTA (17%) as a penultimate rinse — removes smear layer & opens dentinal tubules for disinfection.
⚠️ Why should you avoid mixing CHX + NaOCl as irrigants?
They form a carcinogenic precipitate (parachloroaniline) that is also toxic and stains the tooth.
🕵️♀️ What are signs of post-treatment disease/failure?
Persistent or increasing radiolucency
Sinus tract
Pain, tenderness, or flare-up
Swelling or new infection
Fractures
Missed anatomy on re-evaluation
👑 Why is a crown important after RCT?
Reduces risk of fracture (by 6x)
Provides sealing against coronal leakage
Especially vital in posterior teeth or when marginal ridges are missing
🕰️ When should the crown be placed ideally?
Immediately after RCT to protect the tooth and prevent reinfection or fracture.
🦠 What is a major cause of RCT failure due to coronal restoration?
Poor sealing or leaky restorations allow bacteria to re-enter the canal space.
🔄 What are signs the original disease persists?
Radiographic lesion remains unchanged
Persistent or returning clinical symptoms
No signs of healing despite technically good RCT
What 3 perspectives define “success” in RCT?
Clinician – technical & radiographic success
Patient – pain-free, functional
Biological – infection eliminated, tissue healing
🧬 Why are implants not always a better alternative?
Can be invasive & costly
May not last longer than the natural tooth
RCT preserves natural dentition and has excellent long-term survival
