DIAN - Endodontics

Question 1

Outline the three levels of endodontic treatment complexity - going by the AAE guidelines?

Answer 1

Level 1 - Carried out in practice
Level 2 - Carried out in practice or referral
Level 3 - Carried out in referral

Question 2

When is an endodontic treatment indicated to be of level 1 complexity?

Answer 2

Root canal curvature <30 degrees
No obstructions to access (eg. perforation)
Previous obturation poorly condensed, short of apex
Dismantling of crowns and bridges is required
Emergency treatment (extirpation, drainage)

Question 3

When is an endodontic treatment indicated to be of level 2 complexity?

Answer 3

Root canal treatment between 30 and 45 degrees
Teeth >25mm in length
Canals or consider not negotiable in the coronal third
Limitation of mouth opening
Well condensed
Removal of fractured posts >8mm in length

Question 4

What is meant by the term canal patency?

Answer 4

A preparation technique where the apical portion of the canal is kept clear of debris.

Question 5

When is an endodontic treatment indicated to be of level 3 complexity?

Answer 5

Root curvature >45 degrees
S shaped canals
Canals considered to be non-negotiable for entire length
Developmental abnormalities (bifid apex, complex branching)
Severely traumatized teeth beyond enamel and dentine
Iatrogenic damage or pathological resorption
Posts >8mm in length
Major iatrogenic damage (large ledges, blocked canals, perforations which can be repaired
Periradicular surgery

Question 6

What aspects of the medical history are relevant when assessing patients for endodontic treatment?

Answer 6

Pregnancy (Perform within first trimester)
CV disease (contraindicated if MI within last 6 months)
Cancer (mode of treatment required, consider long term prog)
MRONJ
*For all the above consider liaising with relevant medical professional

Allergies (GP is safe, possible NiTi or latex reaction)

Question 7

What clinical aspects are relevant when assessing patients for endodontic treatment?

Answer 7

Pulpal features (Sinus, abscess, TTP)

Caries status (Consider restorability)

Periodontal status (Deep pockets, pus, mobility, furcation)

Remaining coronal tooth structure

Restorative status (remaining structure, pre-existing crown)

Adjacent tooth status (sound periodontal/apical status)

Question 8

What radiographic aspects are relevant when assessing patients for endodontic treatment?

Answer 8

Previous RCT (seal quality, condensation, within 2mm of apex)

Peri-apical status (PDL widening, apical radiolucency, immature apex)

Root anatomy (number, curvatures, calcifications, resoptions)

Restorative (crown status, crown to root ratio)

Bone levels (contraindication if low)

Caries status (subcrestal is unrestorable, significant caries may prevent isolation)

Question 9

What are the possible risks of endodontic treatment?

Answer 9

Perforation
Instrument separation
Continued symptoms (may not resolve)
Hypochlorite accident
Missed canals
Trismus
Possible need for referral

Question 10

How would you describe the procedure of a routine RCT to a patient?

Answer 10

RCT involves removal of the tooth pulp, disinfection of the root canal systems, and placement of a root canal filling material. A crown may be needed to protect the tooth afterwards.

Question 11

What are the alternative treatment options to RCT?

Answer 11

Accept and monitor
Extraction
Surgical root treatment
Other

Question 12

Outline the procedure for the access stage of a typical root canal treatment.

Answer 12

MH and Consent

Pre-op radiograph (EWL)

Administer LA

Place rubber dam

Remove caries and restorations

Assess restorability (dam must be placeable on subsequent visits)

Cut appropriate access cavity

Question 13

Outline the procedure for the instrumentation stage of a typical root canal treatment.

Answer 13

Carry out coronal prepartions to get straight line access, with ISO files (+/- gates glidden)

Determine CWL (radiograph, apex locator in dry canal)

Instrument canal with appropriate technique (modified step back / crown down)

Carry out recapitulation, patency, and irrigation throughout

Question 14

What is the purpose of 2.5% hypochlorite when irrigating?

Answer 14

Dissolves necrotic and vital biological tissue, acts as an anti-microbial, and acts as a lubricant for instruments.

Question 15

What is the purpose of 17% EDTA when irrigating?

Answer 15

Dissolves the endodontic smear layer
Inorganic tissue
Acts as a lubricant
Chelating agent
Decalcifying agent (useful in sclerosed canals)

Question 16

Outline the procedure for the obturation stage of a typical root canal treatment.

Answer 16

Fill canals with appropriate technique/material

Remove 1mm of GP from the top of the canal to get a good seal.

Seal with RMGIC

Place appropriate core

Assess the need for cuspal coverage

Follow up and restoration of tooth

Review annually for up to 4 years

Question 17

Outline the main principles of obtaining endodontic access?

Answer 17

Allow removal of entire contents of pulp chamber

Allow visualization of the pulp floor and orifices

Allow direct access to apical third of root

Allow retention and support of temporary filling material

Provide reservoir for canal irritant

Be as conservative as possible

Question 18

Describe how you would breach the pulp chamber, and open it sufficiently?

Answer 18

Pierce in a single point where the pulp chamber is expected.

Make an access cavity big enough for a safe-ended endo access bur, to ensure the pulpal floor is not damaged.

Design an appropriate shape for the tooth, allowing straight line access, whilst being as conservative as possible.

Question 19

How should hypochlorite be handled when irrigating?

Answer 19

Use a side vented needle, and continuously move the needle back and forth to prevent extrusion into the apical tissues.

Ideally use your forefinger, not you thumb as you are doing this.

Pass the needle behind the patients head, being aware of droplets when handing to assistant.

Question 20

How can the hypochlorite be activated when in the canal, and why is this important for chemo-mechanical disinfection?

Answer 20

Specialized endo ultrasonics, photoactivated disinfection, sonics, preheated hypochlorite.

The root canal system is complex and may have obstructions, activation helps to penetrate the root canal system.

Question 21

Outline a routine canal prep on a single rooted tooth, using the modified step back technique.

Note: Irrigation protocol is not needed in this explanation.

Answer 21

Scout the canals with a size 10 K file

Carry out coronal pre-flaring (gates glidden sizes 2/3s, only in the coronal to a few mm)

Prepare the coronal two thirds

Establish the CWL using apex locator/radiographs, this should be 0.5-1mm short of the apex.

Establish a glide path with a size 10 K file

Prepare the apical 1/3 to 3 sizes large than the first file to bind at the apex using a watch winding technique.

Consecutively work up a file size, stepping back 0.5-1mm each time, until it joins the coronal prep.

Question 22

What should you do if there is an abscess, uncontrolled bleeding, or weeping canals?

Answer 22

Dress the canals with non-setting calcium hydroxide, and leave for 2-4 weeks to resolve.

Review after this time to clean and assess if it is now appropriate to obturate.

Question 23

Outline the different types of canal prep.

Answer 23

Apical to coronal:
- Standardized
- Step back
- Modified step back

Coronal to apical:
- Step down
- Crown down
- Hybrid
- Double flared
- Modified double flared
- Balanced force

Question 24

What is the purpose of preparing the coronal aspect of the root canal system before the apical?

Answer 24

Improves tactile sensation
Minimizes bacteria infiltration into the apical portion/tissues
Allows for a more accurate working length

Question 25

Outline a routine canal prep on a single rooted tooth, using the crown down technique.

Answer 25

Scout the canals with a size 10 K file

Carry out coronal pre-flaring (gates glidden sizes 2/3s, only in the coronal to a few mm)

Prepare the coronal two thirds

Establish the CWL using apex locator/radiographs, this should be 0.5-1mm short of the apex.

Establish a glide path with a size 10 K file

Use an appropriate file for the canal, using the selected rotary system.

Use files in sequence, with a brushing motion away from the canal.

Question 26

What steps should be taken in the event of hypochlorite accident?

Answer 26

Stop procedure

Inform the patient

Irrigate with copious saline

Leave tooth open for drainage

Administer long acting infil.

Prescribe amox or metro

If e/o swelling 30% greater than healthy contralateral, refer.

Question 27

Give four options for obturation of the root canal.

Answer 27

Cold lateral compaction

Warm vertical/lateral compaction

Thermoplasticized GP injection

Continuous wave compaction

Question 28

How can you ensure the canal is properly disinfected before the root canal stage?

Answer 28

Appropriate irrigation regime used throughout prep.

Final 1 min EDTA rinse
Followed by thorough hypochlorite rinse.

Question 29

Outline the method of cold lateral condensation to obturate a root canal?

Answer 29

Select master GP cone, and mark at CWL.

Lightly coat master cone in sealer

Seat in canal and confirm it goes to length.

Select finger spreader, set it to 1mm short of CWL, and place alongside master GP.

Dip accessory points in sealer, and repeat process.

Remove excess GP, 1mm below orifice to ensure seal.

Question 29

How can the pulp chamber be cleaned prior to core placement after obturation?

Answer 29

Cotton wool dipped in alcohol

Ultrasonics

Question 30

How can ledges be avoided during endodontic preparation?

Answer 30

Good access cavity design
Straight line acesss
Pre curved files
Lubrication
Watch winding motion
No excessive force

Question 31

What risks are associated after an endodontic perforation has occurred?

Answer 31

Pain
Swelling
Bruising
Trismus
Missed canals
File fractures
Hypochlorite accident
Need for more visits
Need for referral

Question 32

What steps can be taken to repair a perforation?

Answer 32

Repairing of the perforation using calcium silicate cements (MTA/Biodentine).

ZOE or GIC can also be used.

Both options require selling over with GIC before continuing on with the RCT.