Contemporary Preparation and Obturation Techniques

Question 1

what is the objective of a RCT

Answer 1

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

summary of objective of a RCT?

Answer 2

 Access the root canal system
 Chemo-mechanical preparation of the
canals
 Obturation of the canals
 Restoration of the tooth

Question 3

what are we looking for in chemo-technical prep?

Answer 3

 Oversimplification but…….
 Instrumentation phase
 Irrigation phase

Question 4

how do we instrument?

Answer 4

• Hand, rotary, reciprocating, swaggering,
  adapting, conforming, self- adjusting…….
   Each technique / file system has its place eg. some teeth prefer different instruments
   Before use, essential to have good
  knowledge of how they work, their pros and cons
   Then can be applied them to an individual case, either as a system or as a hybrid technique

Question 5

describe NiTiNOL?

Answer 5

 Flexible
 Resistant to fracture when placed into
curved root canal (up to a point…..)
 resistant Torsional failure
 Cyclic fatigue failure = ensure file moving up down

Question 6

what are some NiTiNOL developments ?

Answer 6

 Many contemporary files are now made
from heat treated ‘M-wire’
 R-phase NiTi
 Hugely increased resistance to CF
failure which allows for more inventive
movements and file designs
- makes them more flexible

Question 7

what are some of the current file systems ?

Answer 7

 Protaper Gold
 Protaper Next
 Wave One Gold
 Reciproc
 Twisted File Adaptive
 Mtwo
 BioRace
 And the list goes on

Question 8

describe Protaper gold

Answer 8

 Rotary file, uses heat treated NiTi
 Same geometry as Protaper Universal,
variable taper
 Almost all cases can be treated using
this system

Question 9

pros and cons of proper gold

Answer 9

 Flexibility both good (curvature) and bad (sclerosed canals can causes bends)
 Number of files in the system when
using manufacturer’s protocol
 Increased resistance to CF failure

Question 10

describe wave one gold ?

Answer 10

 Reciprocating file
 Same heat treated NiTi as PT Gold
 Rotates 150 degrees CCW then 30
degrees CW

Question 11

pros and cons of wave one gold

Answer 11

• Simple system
   Good CF failure resistance
   Minimal engagement with canal wall reduces torsional failure
   Can create ledges if forced
   Need to use orifice opening file in sclerosed canals

Question 12

cost of files ?

Answer 12

 Protaper Gold £9 (x4?)
 Protaper Next £13 (x2?)
 Wave One Gold £9 (x1?)

Question 13

why is WL determination and canal prep important ?

Answer 13

 Need to know where you want to finish
 Anatomy of the apical region

Question 14

WL anatomy

Answer 14

Question 15

what are the 2 commonly used methods to figure out WL?

Answer 15

x-ray
apex locator

Question 16

what is the zero reading ?

Answer 16

 The “Zero” reading is the point where
the hard and soft tissues meet
 Instrumenting to this point will invariably
lead to damage at the apical constriction
 Depending on skill with instruments
consider working up to 1mm back of
this, whilst maintaining patency

Question 17

what are some objectives with instrumentation phase ?

Answer 17

 Preparing a shape that you can irrigate
and obturate
 Conflicting evidence on what the optimal
shape is
 Schilder’s principles still hold good

Question 18

what is schilders design objective ?

Answer 18

 Continuously tapering funnel from the
apex to the access cavity.
 Cross-sectional diameter should be
narrower at every point apically.
 The root canal preparation should flow
with the shape of the original canal.
 The apical foramen should remain in its
original position.
 The apical opening should be kept as
small as practical

Question 19

what is the Instrumentation protocol using
Protaper Gold?

Answer 19

 Estimate from pre-op radiograph
approximate WL, and also length to
curve
 Place hand file to curve or as far as it
will go passively and open to size 15
 Coronal flare, using XA to curve with a
brushing motion away from the furcation
 Use hand file and EAL to get Zero reading
 Prepare to Zero minus 0.5mm with S1/S2
 Gauge apex to decide on MAF and recheck
with EAL
 F1/F2 to length

Question 20

what is the instrumentation protocol using
Wave One Gold?

Answer 20

 Prepare glidepath by hand to curve
 Coronal flare with Wave One primary file
to curve (can use GG or SX)
 Establish WL with EAL, gildepath
creation by hand to length
 Take WaveOne file to length using up
and down motion – 3 strokes and out
 Gauge once at length – decide on
finishing size

Question 21

why do we irrigate?

Answer 21

 Many irrigants have been developed
and tried over the years
 Best evidence shows that NaOCl 2%
gives the best outcomes
 Can heat it, increase concentration but
no substitution for constant exchange
and refreshment within the canal
 Irrigate during instrumentation phase,
but remember irrigant only goes 1mm
beyond needle tip
 Most effective irrigation after preparation
phase completed
 Keep syringe moving in the canal, don’t
wedge, side vented needle
 Use some form of irrigant activation to
disrupt biofilm and encourage irrigant
into lateral and accessory canals

Question 22

what is the gold standard for obtuaring ?

Answer 22

cold lateral

Question 23

what is the aim of obturation

Answer 23

 Aim of obturation is to create as good a
seal as possible, without extrusion of
material into the periapical tissues
 Not possible to get a good obturation result unless principles of good preparation have been followed, no matter what
manufacturers claim
 Obturation per se does not lead to healing

Question 24

what problems do we face when obturating?

Answer 24

• complexity of RC system eg. multiple lateral canals

Question 25

what are they different obturation techniques ?

Answer 25

 Cold lateral = – still possible to get a ‘3D’
fill with correct technique and Very useful where apex is blown or canal anatomy does not lend itself to creation of retention / resistance form and simple and cheap
 Warm lateral
 Warm vertical
 Carrier based
 Paste
 Cement

Question 26

what are the pros of heated obturation techniques ?

Answer 26

– Demonstrate more 3D fill
 Reduce leakage in leakage studies
 Can be quicker but still time consuming to do properly
 Risk of extrusion / loss of apical control
much higher

Question 27

what is warm vertical compaction ?

Answer 27

 Schilder or Continuous Wave
 Master cone into canal, downpack with
System B, introducing heat as close to the
apex as possible
 Backfill with Obtura
 Seal canal orifice with barrier – IRM or GIC
- most utilised technique
- get more 3d fill

Question 28

how do we choose what obturation technique to choose?

Answer 28

 Consider what canal preparation and
shape you have got – obturate
accordingly
 Cold lateral will work in vast majority of
cases and give a predictable outcome
 If the obturation doesn’t work out,
consider altering the preparation

Question 29

summary

Answer 29

 There are lots of different ways to prepare and obturate root canals
 Think what you are trying to achieve
mechanically and biologically
 First principles of preparation and
obturation are the same however you do it
 When you encounter a problem, always go back to the first principles