Contemporary Prep and obturation

Question 1

what is the expectation of RCT according to European soceity of endodontology?

Answer 1

ž The objective of RCT is to shape, then clean, the root canal system on order to remove micro-organisms, their metabolic products and potential substrate. Once this chemo-mechanical preparation is complete then to seal the root canal as well as possible to create a favourable environment for healing

Question 2

what are the two phases of chemo-mechanical prep

Answer 2

instrumentation
irrigation

Question 3

what are the two types of instrumentation that can be used to prepare the canal

Answer 3

hand instrumentation
Automated instrumentation - rotary

Question 4

what are the pros of using protaper gold file system?

Answer 4

• creates variable taper – the prep is not the same all the way along the canal – this is pro as it means only parts of the file is in contact with the canal wall so that reduces torsional failure

-we can treat almost all cases with this system
- flexible for curved canals, increased resistance to cyclic fatigue failure preventing risk of fracture

Question 5

what are the cons of protaper

Answer 5

flexible so in sclerosed canals when you add force it will bend whereas other systems will progress through the sclerosed canal

Question 6

wave one gold is a reciprocating file, how does this file rotate

Answer 6

rotates 150 degrees CCW then 30 degrees CW

Question 7

pros for wave one gold

Answer 7

Simple system with one file, good cyclic fatigue resistance as it is not constantly rotating, minimal engagement with canal wall which reduced torsional failure,

Question 8

cons for wave one gold

Answer 8

Can create ledges if forced, need to use orifice opening file (Sx file or gates glidden) in sclerosed canals

Question 9

which file is best for extremely curved canals

Answer 9

Waveone as Waveone has more restricted movement which is good for limited access

Question 10

what is the anatomical name for the landmark where the tooth ends and it is the transition of hard tissue to soft tissue

Answer 10

apical constriciton

Question 11

at which anatomical landmark do we need to aim to finish our obturation

Answer 11

apical constriciton

Question 12

what 2 methods can be used to determine the working length?

Answer 12

Diagnostic radiograph
electric apex locator

Question 13

what is the limitation of using diagnostic radiograph

Answer 13

if you take a radiograph it may look like the file is going to length but if you take another radiograph from another angle it will show the file is going past the apex

Question 14

what is the limitation of using apex locator

Answer 14

very accurate however in some cases we are unable to get to the apex so the apex locator is not of use in these cases

Question 15

how can we overcome the limitations of the two methods used to determine working length

Answer 15

can use both – use preop radiograph to determine WL, use apex locator to double check, if there is a significant difference between the two then take diagnostic radiograph to further assess what is going on

Question 16

why is chemical preparation of the chemo-mechanical prep so important?

Answer 16

the files will not contact all parts of the canal walls so chemical irrigation will reach those untouched parts of the canal

Question 17

what can be used as irrigant activation

Answer 17

master GP point

Question 18

why is irrigant activation used

Answer 18

use irrigant activation to disrupt biofilm and encourage the irrigant into the canals

Question 19

how do we use irrigant activation?

Answer 19

works by putting irrigant into the canal then getting GP pumping it up and down about 15 times very fast then repeat for another round of irrigant and repeat this cycle 10 times per canal

Question 20

what is the gold standard obturation technique

Answer 20

cold lateral compaction

Question 21

does obturation play a role in healing

Answer 21

no it is just a seal

Question 22

what clinical scenarios would lead to obturation being difficult

Answer 22

numerous lateral canals
isthumuses are awkwards

Question 23

what are the 6 obturation techniques

Answer 23

• Cold lateral compaction
• Warm lateral compaction
• Warm vertical condensation
• Carrier based
• Paste
• Cement

Question 24

in which clinical scenario is it best to use cold lateral

Answer 24

when apex is blown or canal anatomy does not create retention/resistance form and it is simple and cheap

Question 25

when do heated obturation techniques work best

Answer 25

larger canals where it is difficult to get a good seal

Question 26

what are the advantages of using heated technique for obturation

Answer 26

• More of the canal is filled – 3D fill
• Reduce leakage

Question 27

what is the disadvantage of using heated technique for obturation

Answer 27

• There is risk of extrusion is higher when you use this technique if there is not good retention in the prep, or the apex is open due to inflammation or the root has previously been filled and the apex was damaged in the process

Question 28

why is cold lateral obturation technique the gold standard

Answer 28

it works for most cases and is predictable

Question 29

if obturation does not work what must we consider

Answer 29

altering the prep

Question 30

if patient’s radiograph shows significant internal resorption of root what obturation technique is best for this scenario

Answer 30

Warm technique is the only technique that would work for this problem to allow the sealant to extend past the void

Question 31

if patient’s radiograph shows no taper (bad for cold lateral) of root and there is a wide apex (bad for warm obturation) then how would we obturate this canal

Answer 31

plug apices with MTA plug and then fill the rest with gutta percha