|
Endodontics |
Dr. Julian Webber
Management of
Endodontic Failure
Dr. Webber
opened with compliments to
Management
of Endodontic Failure is an important issue because the standards of Endodontics
around the world are poor, therefore we have many failures to deal with and
retreatment is a big part of many practices. We need to know how to save some
of these teeth lest they end up as fodder for the Implantologists.
Firstly, we need a Biological and Anatomical understanding of Endodontic
Success and Failure. Rather than use the term Apical Periodontitis (AP), Dr
Webber prefers the term Periodontitis of Endodontic Origin (PEO) because we all
know PEO can occur anywhere around the surface of the root that is inside the
supporting bone – not just apical. He quoted classic studies by Kakehashi (1965)
Moller (1966, 81) and Sundqvist (1976). Failures are undoubtedly bacterially
related. We need to eradicate or eliminate the bacteria to a sufficient level,
we will get healing. We must also
eliminate the substrate that the bacteria thrive upon. However, the complexity
of the RCS anatomy makes this is a tall order.
Aim of Treatment:
We need to eliminate infection in the canal system and at the same time add a
coronal seal to enhance the apical seal at the end of the RCS. (Quotes Sjogren 97 Saunders
& Saunders 94 Ray and Trope.) Although widely quoted, we shouldn’t
let Ray and Trope’s study (that showed that quality of coronal restoration was
sometimes MORE important than the quality of the endodontic treatment) be too
influential. We need to do the best possible job in all aspects of treatment –
eliminate bacteria, eliminate the substrate, fill in 3D and have a good coronal
seal – in order to have optimal treatment success.
The
quality of endodontic treatment around the world is generally poor. He showed a
chart of studies of the
Chart - Prevalence and Quality of Endodontic Treatment: Inadequate Treatment
(where filling is not within 1-1.5 mm from radiographic apex). 10 studies from
Eu and N. Am. were shown (1990-2002). Success rates varied from as high as 87%
to a low of 50%. Webber makes an excellent point: While we on roots continue to
debate the merits of filling to the RT or patency – if we could just teach the
General Practitioners of the world to clean adequately to within 1 mm of the
apex and then put in a quality endodontic filling with a good coronal
restoration, we would see much better results for Endodontics in general. While
we Endodontists continue to argue about prep size, taper, location of filling,
puffs and patency, etc. – it will be a
long time before we can persuade the whole world that Endodontic treatment is
predictable, retreatment is predictable and that implants are NOT the answer.
Chart - Prevalence
and Quality of Endodontic Treatment: Inadequate Treatment/Presence of AP
(same studies from Eu and N. Am. (1990-2002)). We see that where the standard
of RCT of poor – the associated level of PA disease is high. We need to elevate
the standards so that these figures are not looked upon with glee by the
Implantologists and are used against us.
In 1986,
the late Dr. Herbert Schilder quoted the term “Retreatdodontics” and said that
“the future of Endodontics lies in the Retreatment of Endodontic Failures”. 75
% of the cases in Webber’s practice are retreatment. Even if our success rates
are in the 90s %, we still have a significant percentage of retreatment that is
required all over the world.
Do Retreatments
work?
Webber quotes Bergenholtz et al Scand J. Dent Res 87 217:233 that states:
Treatments with technical shortcomings could, following retreatment, be
markedly improved as regards effectiveness and distance to apex. Following a 2
year observation period of 556 cases, retreatments carries out because of
technical inadequacies alone were successful in 94% of cases.
Abott
PV (Aust Dent J.1999) A retrospective analysis of the reasons for and the
outcome of conservative endodontic retreatment and periradicular surgery
- An in office
study 575 teeth over 6 years. 555 (96.5%) were assessed as successful. All
teeth were disassembled/removed all coronal obstructions/coronal caries and
bacteria. When done in this way – (no compromises) 92% success was achieved
after only 3-6 months.
Doornbusch et al IEJ 2002 Radiographic evaluation of cases referred for
surgical Endodontics
278
radiographs of cases referred for surgical endo were assessed by an Oral
surgeon, GP and Endodontist. OS said 41% of cases were amenable to conventional
endo ReTx, GP 67% and the Endodontist 80%. It concluded that most teeth
referred to surgical treatment to an OS could be retreated by orthograde
nonsurgical TX rather than surgical RCT.
Indications for SRCT ReTx
-
Procedural Errors in the apical third. Webber does only about a HALF DOZEN
SURGICAL CASES PER YEAR!! He only does
it in situations where there is no other possible avenue of treatment. He shows
an example of previous tx with badly torn apex – he
did SRCT on this max premolar but said that this was the only SRCT he did
during about 6 months of cases last year.
Retreatment Indications:
·
Failure
of initial therapy or inadequate retreatment
·
Inadequate
root filling radiographically or clinically checked in situ without evidence of
failure in a tooth scheduled for placement of a new restoration. ( It doesn’t
matter if no symptoms or no pathology – it still needs a good endo under the
new restoration)
Problems with Retreatment
·
Frustration
·
Unpredictable
results
·
Profitability
Retreatment Steps
Costing Retreatment Fairly and
Sensibly
Ruddle
(1996) How to profit from Endo: Finding the fair fee for Endodontics
Dent Econ 88(11)30
Retreatment
is “A complex procedure that should cost the patient the same or less than the
alternative to compensate the extra time required to achieve natural tooth
retention.” If you charge the same fee
for conventional tx that you do for ReTx you will:
You must
sell the value of the retreatment of the procedure to your patient. You need to
educate the patient and say that saving the tooth in this manner will cost you
“a little bit less” than having the tooth extracted and replaced with an
implant. Webber feels that, when faced with this decision, most patients would
opt for retreatment. (This assumes that the perio condition is good and that
the tooth can be properly restored.)
Webber
then shows a disassembly case. Crown cut off, core dissected. Post removal,
silver cone removal from core material. Access recleaned, canals shaped and
cleaned and then filled. Webber charges 50% more than conventional endo fee
when retreating a case like this. Webber believes that in situation where the
restorative dentist is not sure as to whether to proceed, the Endodontist
should be the first consult. The Endodontist should be part of the decision
making process.
Dealing with Retreatment
Obstacles
·
Crowns
and Bridges
o
Webber
has tried devices such as Morell, Richwil, Higa, Metalift System and WAMkey.
But in MOST cases, he simply CUTS THE CROWN OFF.
·
Posts
o
Hemostats
and Microsurgical forceps (expensive!)
o
Ultrasonics
o
Dedicated
Post removal devices
§
Thomas
PRS ( has Peezo type drills for going through fiber posts)
§
Gonon
PRS
§
Ruddle
PRS –
Webber prefers to try to ultrasonically vibrate the post
and try to get it out that way. Always use copious water to prevent overheating
of the post during vibration. If he can’t remove it ultrasonically in about
10-15 minutes, he moves on to a post removal system. It is rare that you can
NOT remove a post with one of these PRS systems. You should always warn
patients when post size or length /root size may risk fracture. In that case
SRCT might be a better option. He then
showed the Ruddle PRS video.
·
Silver
Cones
o
Microsurgical
Forceps – ideal for when silver cone heads are sticking up in the chamber
o
Braided
Hedstrom files
o
Ultrasonics - work around the periphery for the cone with
an ultrasonic file
Some cases are best managed by to bypass the silver cones
with very small hand files and then using them to remove the cone with an
outward motion.
·
Gutta
Percha
o
Solvents
§
Webber
is not a fan of solvents because of the sludge of softened GP it creates (Chloroform,
Xylol, DMS IV). If you do use solvents,
you must remove all of it with a paper point wicking technique before you start
re-preparing it.
o
ProTaper
Universal D1, D2, D3 @ 500-700 rpm
§
In
may of 2006 this new ProTaper Universal system was introduced ( except in the
§
D1
file: Removes Filling Material from the coronal third
·
11mm
handle - 16 mm cutting surface
·
White
ring for ID
·
9%
taper matches average coronal diameter
·
ISO
30 active tip for easier penetration of obturating material
§
D2
file: Removes filling material from the middle third
·
11mm
handle - 18 mm cutting surface
·
2
White rings for ID
·
8%
taper matches average mid canal diameter
·
ISO
25 Non active rounded tip to follow canal path
§
D3
file: Removes filling material from the apical third
·
11mm
handle - 22 mm cutting surface
·
3
White rings for ID
·
Reduced
7 % taper matches apical third diameter
·
ISO
20 non active rounded tip to follow canal path
o
Micro
Debrider
§
These
are small files that are constructed with 90 degree bends and are used to remove
any remaining Gutta Percha on the sides of the canal walls/isthmuses after
re-preparation.
Most literature shoes that we cannot remove all the
previously placed filling material.
Wilcox et al JOE 1987 13 453-7 Endodontic Retreatment:
Evaluation of gutta percha and sealer removal and canal reinstrumentation. Canal walls
completely free of debris are not usually observed.
Imura et al Comparison of relative efficiencies of four
hand and rotary instrumentation techniques during retreatment JOE 2000 33
361-66 Overall all
instruments leave filling material inside the root canal
·
Carrier
Based Systems- Thermafil
o
Rotate
ProTaper F1 or F2 into the groove of the carrier @ 800 RPM
o
Rotate
D1,D2,D3 into groove @ 700 RPM
o
Insert
and retrieve with Hedstrom File
Thermafils are not as difficult to remove as
some people may think.
·
Pastes
o
Soluble
ZnO Pastes
o
Insoluble/Hard
Pastes
o
Russian
Red ( Resorcinol based pastes)
Paste removal can sometimes be extremely difficult.
Cohen AG The
efficiency of different solvents used in the retreatment of past e filled root
canals ( Master’s Thesis) BU 1986 The most effective solvents for softening
formaldehyde resin pastes were those that had potentially harmful effects.
Vranas et al JOE 2003 29:69 The effect of endodontic solutions on resorcinol-formalin
paste Endosolve R appeared to become incorporated into the paste
softening it without actually dissolving it.
Jeng and El Deeb
JOE 1987 13 295 – Removal of hard paste fillings from the root canal by ultrasonic
instrumentation
Dr Webber mentions DMS IV as well as Endosolv
R (Septodont) as agents for paste removal as well as
a myriad of ultrasonic tips. He has no favorite manufacturers and suggests that
each of us has our favorite types and brands. Sometimes (
especially with Russian Red) we have to accept some compromises. Because
the tooth structure is stained red it is often difficult to discern where the
tooth is and perforations are easy to make when attempting to remove this
material. We need good magnification and careful ultrasonic .
·
Broken
Instruments
Webber says that we need to have a strategy to do this. We
need to reevaluate the “magnificent obsession” of attempting to remove broken
root canal instruments. He quoted UGH and Berg IEJ 1986 19:2-10 Endodontic
treatment of root canals obstructed by foreign objects
His strategy:
o
In
coronal third – attempt retrieval
o
In
middle third – retrieve or bypass
o
In
apical third – leave and observe
Do we need to remove all broken instruments?
Crump and Natkin JADA 1970 88(3) 134 Relationship of broken root canal instruments
to endodontic case diagnosis 53 cases of inadvertent breakage at apex
compared to 53 controls. 2 year follow up as good as
success from correctly filled canal.
Fox et al 1972
Instruments
twisted off at apex and locked tightly in the canal served to prevent apical
percolation
Therefore in situations where the instrument is broken at
the apex, there must be some consideration made for filling to the level of the
broken instrument and then monitoring the case.
Minimal requirements:
·
Microscope
·
Assistant
should also be able to see (via auxiliary scope or monitor)
·
Webber
likes the Satelec ultrasonic unit and uses various
tips
He uses the Carr technique for modifying a GG bur with a
disc, then creating a staging platform before using an ultrasonic tip to rotate
around the file in a counterclockwise manner to dislodge it. If you can’t see what you are doing – if you
do not have the correct magnification- you should not be doing this.
The secret of removing the instruments broken in the
coronal and middle thirds is understanding how much
coronal tooth structure you have to remove in order to gain access to the
instrument. If we must “over-prepare” the coronal portion to gain access, then
maybe it is a better idea to leave the instrument in place rather than
compromise the coronal dentin.
Cancellier devices and Krazy
Glue can also be used. Sometimes it works, sometimes it doesn’t but you still
must have several different strategies to allow you the option of selecting the
best device for the situation. He showed Ruddle’s IRS
System video. He said that while the video is impressive, it rarely works that
easily. We all have a good laugh while watching how simply the system seems to
retrieve the broken file – he comments that he wishes they all came out that
easily.
·
Bypassing
Broken Instruments
o
Bypass
with K file #8/10
o
Continue
bypass sequence
o
(Dislodge
with Ultrasonic K file #15 or 20
o
Copious
irrigation
He showed a lower molar with a large portion of broken file
in the middle and apical third. The angle of retrieval was such that too much
coronal dentin would have to be removed to allow straight line access to the
coronal part of the file. So he chooses a bypass strategy in this case. The
canal was prepared well enough to incorporate the file into the prepared canal
space. He shows another case that cannot be retrieved or bypassed. He remarks
that breaking a file is not negligent, but NOT telling the patient is
negligence.
Saunders et al 2004 JOE 30(3) 177-179 Effect of separated instrument on bacterial
penetration of obturated root canals The presence of 3mm of a fractured 40/.04 instrument did not speed up
or slowdown penetration of bacteria compared to controls. Extruded
sealer onto flutes equivalent of any other obturation technique. In the
absence of residual infection coronal seal was the most important factor.
In other words, in the absence of a periradicular lesion, (i.e./ a suspected vital case) we should consider leaving the
instrument in place, IF we can do a good job with the rest of the canal system AND we can get a good
coronal seal as well. We need to reconsider the obsession with instrument
removal at the expense of good tooth structure and risk of procedural or
structural compromise.
·
Perforations
o
MTA
is the material of choice (
o
All
the armamentarium associated with it is necessary – i.e./ Dovgan
carriers and Pluggers, Lee Block and instrument
o
Webber
has had success with the MAP system ( Produit
Dentaire) now being sold by Dentsply
as the MTA Gun.
·
Apical
Closure and Perforation Repair
Webber showed a case where the patient insisted that the
anterior tooth be saved. Very large resorbed apex with LEO. An MTA plug was placed and the case
re-restored. He then showed two perforation cases (furca and lateral). We must
ensure that the perf repair material is up against bone because it washes out
of exposed to the oral environment.
Webber
says that that retreatment is hard but that we need to take an optimistic view
when approaching cases. (Tanaka’s Law – 1. Nothing is
as hard as it looks 2. Everything is more rewarding than it seems. 3.
Everything will go right and at the best possible moment)
Single Visit Retreatments:
Webber
usually does SINGLE VISIT RETREATMENT. The only indication for non-completion
of retreatment in a single visit is when he is unable to get the canal
dry. In that case he will fill the other
canals and then treat the wet canal with CaOH. Note: He is the first of several “one
steppers” who will present at the
