Endo Tribune U.S. No. 8, 2011

Additions to the NiTi rotary file market / Endodontic parousia — Nullius in verba redux / Industry

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ENDO TRIBUNE
The World’s Endodontic Newspaper · U.S. Edition

August/September 2011

Additions
to the NiTi
rotary file
market
What to bring in
and what to leave out
By L. Stephen Buchanan, DDS, FICD, FACD

Nickel titanium rotary shaping files fundamentally changed
everything in endodontics; conceptually, procedurally and economically. The efficiencies gained
offset the costs, and dental companies were loved for making files
that cost four times more than SS
hand files but delivered a tenfold
improvement.
Those seeds of success have
grown into today’s endo market
where we have come to expect
another new file on the market
every six months. Granted, it’s a
quality problem, but while some of
these new instruments have significant improvements in tip and
blade geometry or were made with
improved metallurgical and forming processes, some have offered
little advancement over existing
technology.
Their introductions were just
business moves proposed to benefit a dental company instead of
dentists and their patients.
So how do we sort through the
list of new, new instruments and
decide whether any of them truly
offer clinical advantages commensurate with the high cost of
purchasing new instrument inventories, new handpieces and the
retraining needed to become competent in their use?
To my mind, there are only a
few reasons to change to a new
rotary file system:
1) Improved safety and consistency of result.
2) Improved efficiency if the
safety and outcomes imperatives
have been met or exceeded.
3) Improved procedural simplicity and/or cost of providing
endodontic services to patients.
In that order! Any new instrument delivering improved efficiency at the cost of safety and
predictability of outcome is a fool’s
choice. So if we are choosing for
g ET page 2B

www.endo-tribune.com

Vol. 6, No. 8

endo opinion

Endodontic parousia —
Nullius in verba redux
By Ken Serota, DDS

The intent of this article is to see
whether I can finally shake up those
of you who read my blog (on www.
oralhealthjournal.com), spend time
on it and yet do not post. The point
of this “mashup” is to engender “discovery” of information, trends, likes,
dislikes, etc., and to dialogue in the
truest manner and context of social
networking within this profession.
Read away McDentist and offer your
commentary — good, bad or indifferent — but never overlook the opportunity to make your voice heard.
Every era lives with contradictions
that it manages to ignore: the Greeks
talked of justice and kept slaves,
the Crusaders preached the gospel
of the Prince of Peace and rode off
to annihilate the infidels, and the
17th century believed in a universe
that ran like clockwork, entirely in
accord with natural law, and also in
a God who reached down into the
world to perform miracles and punish sinners.1
Historically, the decision to perform endodontic therapy and restore
a tooth or to extract and replace it
in some manner was a relatively
“straight-line” decision; however, in
the implant-driven treatment planning era of the new millennium, dentists face a multitude of complicating
factors, most notably the irrefutable
success of dental implant therapy
and the relative ease and facility of
“nuts and bolts” restoration, provided the foundational aspects of
surgical placement are met.2
As a discipline specifically and
as a profession in general, we must
ensure that our process does not
engender “rearranging the deck
chairs on the Titanic”.3 The identification and quantification of specific factors that affect rehabilitative
prognosis in individual patients are
essential to formulating standardized
treatment protocols and individual
treatment plans. Such factors include
bone quantity and quality, caries and
periodontal disease risk, as well as
the critically important factor of the
amount of remaining tooth structure.
Minor or even moderate differences in overall treatment outcomes
or costs must not affect clinical decisions and must not sway critical

Fig. 1: Images of perfusion studies to illustrate the complexities of the rootcanal system of all tooth types.10
thinking.4 Endodontics mandates, as
does any discipline, the aggregation
and verification of scientific knowledge and proof in order to create the
proficiency inherent in the desired
positive treatment outcomes; it does
not manifest as a paint-by-numbers
technical approach whereby the illusion of science is discernible only in
the design and perceived innovation
of the equipment or product brought
to market without retrospective studies or meta-analyses of multivariate,
multicentre treatment outcomes.
In a Madoffian world, it is lunacy
to be driven by guru-centric claims
and pronouncements.
It would be disingenuous and gratuitous to suggest that condemnation
of salvageable and healthy teeth has
not reached epidemic proportions.
Yet, the treatment outcomes studies
on implant survival for the most part
report survival as a binary outcome
rather than using the Kaplan–Meier
survival analysis, which is a far more
accurate reflection of the percentage of success.5 It is because binary
outcome has been the benchmark to
justify removal of salvageable teeth
that the pendulum swung too far too
fast.
Dentistry needs a “Sputnik”
moment to reinvigorate our basic
tenets and grounding funda-

mentals. Sadly, endodontists are
infrequent visitors to the criticalthinking, treatment-planning loop,
as the technological simplification of
the discipline is negating its biological contribution to the interdisciplinary team approach.
This article serves to determine
whether endodontics as a specialty
has made a case for true partnership
in the landscape of foundational,
interdisciplinary dentistry. Its intent
is to assess the innovations and iterations in the toolbox of the endodontic
discipline and ensure that retention
of natural teeth is keeping pace with
biological reality and not marketing
budget-driven science.
There are two historic milestones
that bracket our understanding of
the myriad complexities of the rootcanal system; the first, the work of
Hess, was woven into the fabric of
the era of Focal Infection Theory
and stimulated the annihilation of
millions of salvageable teeth and
put dentistry firmly back in the Dark
Ages of science (Fig. 1).
The second, the use of micro-CT
technology to map the inner space
of teeth, replicated the Hess studies
using digital tools (Fig. 2). Unfortunately, the outcome of this renewed
g ET page 4B

[2] =>

Instrumentation

f ET page 1B

excellence of outcome, we usually
look at our failures and consider how we could eliminate those
painful and expensive experiences
from practice.
However, deconstructing endodontic failures can be nearly
impossible, so it is imperative for
dentists to choose for the right
reasons.
One of the greatest challenges
to dentists making these decisions
wisely is the difficulty of deconstructing endodontic failures —
the prime example being failures
due to apical damage caused by
aggressive tip and flute geometries.
Dentists who use rotary files
have all suffered instrument separation when difficult anatomy is
encountered and rotary files are
allowed to rotate for too long.
This is why dentists interpret a
new rotary file that cuts effortlessly to length in such positive
light, despite the reality that serious laceration will almost always
result when aggressive tip and
blade geometry intersects difficult
apical anatomy.
The only evidence of the disastrous shaping outcome is the inevitable overfill that follows — a
result seldom attributed to its true
etiology but most commonly identified as a cone fit or condensation
failure.
When a given file design always
cuts to length, it is highly unlikely to exhibit fidelity to the original canal path in apically curved
canals. Combining that fact with
the fact that at least half of all canal
curvatures are hidden in our conventional radiographic imaging, it
makes an incontrovertible case for
safety above cutting efficiency if
only one of these two attributes is
designed into an instrument set.
That leaves us to consider new
files introduced to solve mythical
problems not proven to exist or
to deliver efficiencies provided by
already existing instruments that
have been around for a decade.
The best example being the
SAF (self-adjusting file) brought to
market and abandoned less than
a year later. This cardiac-stentlike file, truly a beautiful design
as its hyper-flexible, cross-laced
struts are laser-cut out of NiTi tube
stock, was hailed as a transformational file, and that it is.

Tell us
what
you
think!

What it isn’t, though, is an
instrument that cuts dentin but
rather only sands it, thus creating no reproducible canal shape
and catapulting us back to an era
before system-based endodontics
related obturation procedures to
specific pre-defined shaping outcomes. Oh, and there was also the
issue of needing to buy a proprietary handpiece/irrigation device
and a $50 cost per instrument. So
whose bottom line was in mind?
Not yours.
Another example is the recently
introduced reciprocating file.
What problem does this solve for
you? Do you need to spend money
on a new handpiece and learn
an entirely different technique for
shaping canals that won’t improve
your results or your bottom line?
And is the claim that you can cut a
shape with one file entirely true or
even new for that matter?
Single-file shaping is not a new
or unique claim, as GT and later
GTX Files have cut single-file
shapes since 1996. And, as I have
understood since I first proposed
a single file concept and successfully designed a file line that could
accomplish that outcome, there is
no file design that can cut a singlefile shape in all canals.
Two to three files to cut shape in
a nasty root? Sure, but nobody gets
a single file to length in that one.
The large roots with huge apical
canal diameters? Two should do it,

Endo Tribune | August/September 2011
but nobody is shaping that canal
with a single file.
Small canals with significant
curvature or constriction cannot be shaped with a single file
without risk of instrument separation, and canals with larger apical diameters will usually require
two instruments — one to cut an
initial shape so that the terminal
diameter of the canal can be accurately gauged and the second file
to finish.
With GTX Files, 95 percent of
canals can be shaped with one to
two files in less than a minute, and
half of all medium-sized canals (in
large molar roots) are completed
with just one 30-.08 GTX File. This
is while using any existing rotary
handpiece and a technique you are
familiar with. So this new “singlefile shaping” claim is neither new
nor true.
So what do you bring in and
what do you leave out? The biggest improvement happening in
my clinical practice is the introduction of full rotary negotiation.
And for this giant step forward, you
don’t need a new handpiece; these
files work well in the handpiece
you are currently using.
So two things to keep in mind
here: First, if it ain’t broke, don’t
fix it; and second, be certain before
you make the investment to buy
into a new rotary shaping system
that it solves a problem you actually have. ET

ENDO TRIBUNE

The World’s Endodontic Newspaper · U.S. Edition

Publisher & Chairman
Torsten R. Oemus
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r.goodman@dental-tribune.com
Editor in Chief Endo Tribune
Frederic Barnett, DMD
BarnettF@einstein.edu
International Editor Endo Tribune
Prof. Dr. Arnaldo Castellucci
Managing Editor/Designer
Implant, Endo & Lab Tribunes
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s.rendon@dental-tribune.com
Managing Editor/Designer
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ET About the author
Dental Tribune America, LLC
116 W. 23rd St., Suite #500
New York, NY 10011
Tel.: (212) 244-7181
Fax: (212) 244-7185

Dr. L. Stephen Buchanan,
DDS, FICD, FACD is a diplomate of the American Board of
Endodontics and an assistant
clinical professor at the postgraduate endodontic programs
at USC and UCLA.
He maintains a private practice limited to endodontics and
implant surgery in Santa Barbara, Calif., and is the founder
of Dental Education Laboratories, a hands-on training center
serving general dentists and
endodontist upgrading their
skills in new endodontic and
implant technology.
Buchanan can be reached
through his business, Dental
Education Laboratories, at
www.endobuchanan.com or
info@endobuchanan.com.

Do you have general comments or criticism
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Published by Dental Tribune America
© 2011 Dental Tribune America.
All rights reserved.
Dental Tribune America makes every effort
to report clinical information and manufacturer’s product news accurately, but cannot
assume responsibility for the validity of product claims, or for typographical errors. The
publishers also do not assume responsibility
for product names or claims, or statements
made by advertisers. Opinions expressed by
authors are their own and may not reflect
those of Dental Tribune America.

Editorial Advisory Board

Corrections

Endo Tribune strives to
maintain the utmost accuracy in its news and clinical reports. If you find
a factual error or content that requires clarification, please report the
details to Managing Editor
Sierra Rendon at s.rendon@
dental-tribune.com.

Frederic Barnett, DMD (Editor in Chief)
Roman Borczyk, DDS
L. Stephen Buchanan, DDS, FICD, FACD
Gary B. Carr, DDS
Prof. Dr. Arnaldo Castellucci
Joseph S. Dovgan, DDS, MS, PC
Unni Endal, DDS
Fernando Goldberg, DDS, PhD
Vladimir Gorokhovsky, PhD
Fabio G.M. Gorni, DDS
James L. Gutmann, DDS, PhD (honoris causa),
Cert Endo, FACD, FICD, FADI
William “Ben” Johnson, DDS
Kenneth Koch, DMD
Sergio Kuttler, DDS
John T. McSpadden, DDS
Richard E. Mounce, DDS, PC
John Nusstein, DDS, MS
Ove A. Peters, PD Dr. med dent., MS, FICD
David B. Rosenberg, DDS
Dr. Clifford J. Ruddle, DDS, FACD, FICD
William P. Saunders, Phd, BDS, FDS, RCS Edin
Kenneth S. Serota, DDS, MMSc
Asgeir Sigurdsson, DDS
Yoshitsugu Terauchi, DDS
John D. West, DDS, MSD

[3] =>

ENDO Tribune | April 2011

Industry Opinion & Products 3B

[4] =>

4B

Endo Opinion

Endo Tribune | August/September 2011

f ET page 1B

awareness has not resulted in a more
sophisticated approach to preservation of natural teeth using a century
of evolutionary advances in material and technique, but has fostered
a “simpler is better” mentality, which
will inevitably be as devastating to
retention of the natural dentition as
Dr. Hunter’s egregious dental witch
hunt of the early 1900s.6
The hard-tissue repository of the
human dental pulp takes on numerous configurations and shapes. A
thorough knowledge of tooth morphology, careful interpretation of
angled radiographs, use of small FOV
CBT, proper access preparation and
detailed exploration of the interior of
the tooth are essential prerequisites
for a successful treatment outcome.
A thorough understanding of the
complexity of the root-canal system is
essential for understanding the principles and problems of debridement,
disinfection and root filling for determining the apical limits and dimensions of canal preparations and for
performing successful microsurgical
procedures when necessary.
And yet, the past few decades have
been entombed in the most egregious
nihilistic “Mad Men” description of
the technological wizardry and biological understanding necessary to
ensure long-term predictable prognosis of the endodontically treated
tooth: “clean, shape, pack.” This
has produced a plethora of product
launches that has now reached its
crescendo with the arrival of a “single
file that does all.”
From a metamorphosis of instruments borne of angioplasty materials
to the enhanced elasticity of NiTi and
its reformulation in newly ground
shapes and its use in reciprocating
rather than rotary feed rates, the
market is once again driving science,
and our patients and ultimately our
profession will pay the price for the
oversimplification and obtuse denial
of the reality we know for the expediency we are being trained to crave.
Sealers based on restorative fundamentals were to be the sine qua
non of monobloc creation in the rootcanal space. Unfortunately, one of the
most exhaustive studies done to evaluate evidence-based support on the
merits of their clinical use concluded
that “on the basis of the in vitro and
in vivo data available to date, there
appears to be no clear benefit with
the use of methacrylate resin-based
sealers in conjunction with adhesive
root filling materials at this point in
their development”.7
Science has shown that the direction for eradication of refractory and
chronic disease related to biofilm
elimination lies in photodynamic
therapy, which has provided clear
evidence of clinical efficacy, and
applicability continues to be demonstrated.8 And yet, an array of sonic
and ultrasonic products have infused
the market with specious claims to
optimize microbial control through
innovations in irrigation protocols
designed to disinfect and remove the
smear layer of the prepared rootcanal space in spite of the fact that

Fig. 2: Micro-CT images of a molar tooth. (Photos/Provided by the Root Canal Anatomy Project; http://rootcanal
anatomy.blogspot.com/).
their ability to remove mixed-species
biofilm remains unproven.
The great virtue of mathematics
is that its truths alone are certain
and inevitable; in any universe, the
shortest distance between two points
is a straight line. And yet, the pundits of the new wave in endodontics
would have us believe that single
files — regardless of their envelope of
motion, be it reciprocating, rotary or
piston-like — can effectively debride
the negative space of the root-canal
system in defiance of the morphometrics and myriad complexities of the
inner world of teeth.
Similarly, insubordinate to the science of rheology, carrier-based obturation is deemed equivalent to the
force generation and resultant gravitometrics of injection-moulded, warm
thermolabile techniques as described
initially by Blaney and made mainstream by Schilder.
And yet, we have a new wave of
carrier-based obturation devices that,
in concert with simplified instrumentation protocols, are being marketed
by their developers in the context
that, “I have read this argument about
making root-canal treatment simple.
Many colleagues struggle with the
complexities of root-canal treatments, and I do not see why we
can’t make it simpler. Any competent
dentist has good manual skills. If we
can simplify the treatment procedure
for the general dentists and thereby
improve their skills in completing
more root-canal treatments to a higher standard, our patients will surely
benefit.”9
For those who would suggest that

this article is self-serving, I would suggest that you simply replace the discipline cited with any other. Perhaps
we have reached the point that we no
longer wish to advance and support
the art and science of ________ (fill
in the blank) with definitive research
that will refute the nattering nabobs
of nihilism on the other side of that
proverbial line in the sand. It is time
for dentists to acknowledge the gravity of the problem where industry
is the driver and the profession the

passenger. We need leadership to
regenerate the science of dentistry before the artistry truly becomes
pre-planned and pre-programmed by
those outside the profession, whose
vested interests lie in profit and loss
statements and not in the eradication
of oral disease. ET
Editorial note: A complete list of
references is available from the publisher. Send comments on this article
to c.salwiczek@oemus-media.de.

ET About the author
     Dr. Kenneth S. Serota graduated from
the University of Toronto in 1973 and
was awarded the George W. Switzer
Memorial Key for Excellence in Prosthodontics. He received his certificate in
endodontics and master of medical sciences degree from the Harvard-Forsyth
Dental Center in Boston.
     A recipient of the American Association of Endodontics Memorial Research
Award for his work in nuclear medicine
screening procedures related to dental pathology, his passion is education
and, most recently, e-learning and rich
media. Serota provided an interactive
endodontic program for the Ontario
Dental Association (ODA) from 1983 to
1997 and was awarded the ODA Award
of Merit for his efforts in the provision
of continuing education.
     The author of more than 60 publications, Serota is on the editorial board
of Endodontic Practice, Endo Tribune
and Implant Tribune. He founded
ROOTS, an online educational forum

for dentists from around the world
who wish to learn cutting-edge endodontic therapy, and recently launched
IMPLANTS (www.rximplants.com) and
www.tdsonline.org in order to provide
dentists with a clear understanding of
the endodontic–implant algorithm
in foundational dentistry.

[5] =>

ENDO Tribune | August/September 2011

Industry 5B

2Seal easymiX Root Canal Sealer by Roydent Dental Products
Roydent Dental Products recently announced the release of 2Seal
easymiX Root Canal Sealer. 2Seal
easymiX is an easy-to-use, auto-mix
epoxy resin sealer. The double chamber syringe guarantees a consistent,
ideal mix ratio with less waste.
“We are excited to offer this solution to our customers,” said Nancy
Connor, Roydent’s sales and marketing manager. “2Seal easymiX is
a safe and ideal way for doctors to
achieve one-handed dispensing and
precise placement in the canal. It
is also extremely radiopaque and
biocompatible.”
This sealer is so versatile it may

be used with any obturation method:
warm, heated or cold techniques,
Connor said.
Additionally, the new mix tip is
designed with 360-degrees Flex,
which rotates 360 degrees for easy
maneuvering, enabling clinicians to
place the sealer directly in the root
canal system at any angle.
2Seal easymiX is available from
any authorized Roydent Dental
Products distributor.
For more information on
Roydent
Dental
Products,
call (800) 992–7767 or visit
www.roydent.com.

Roydent Dental Products
introduces 2Seal easymiX,
an easy-to-use, automix epoxy
resin sealer. (Photo/Provided
by Roydent Dental Products)

File Removal
System from
DENTSPLY Tulsa
Dental Specialties

File Removal
System.
(Photo/
Provided by
DENTSPLY
Tulsa Dental
Specialties)
Ultrasonics remains the procedural choice when removing intracanal obstructions lodged deep within
the root canal system. On occasion,
ultrasonic trephining procedures are
limited or prove ineffective.
In these instances, the File Removal System may be utilized to mechanically engage and potentially remove
intracanal obstructions, such as silver points, carrier-based obturators
or broken file segments. The system
was designed by Clifford J. Ruddle,
DDS, and is available in three sizes:
black (19 gauge), red (21 gauge) and
yellow (24 gauge).
For more information, call (800)
662-1202 or visit www.tulsadental
specialties.com.

Send us
your case study!
To have a recent case study considered for publication in Endo Tribune,
send your 800- to 1,200-word case
study and up to 12 high-resolution
photos to Managing Editor Sierra Rendon at s.rendon@dental-tribune.com.
Cases will be published pending editor approval and space availablility.

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[cover] => Endo Tribune U.S. No. 8, 2011

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Table of contents

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Additions to the NiTi rotary file market / Endodontic parousia — Nullius in verba redux / Industry

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