roots C.E. No. 1, 2017

Cover / Editorial / Content / Canal preparation and obturation: An updated view of the two pillars of nonsurgical endodontics / Recent advances in 3D-printed dental replicas for procedural training and board exams / 18-month case study of a C-shaped mandibular molar: Preserving dentin and deep cleaning utilizing an innovative procedure / Dentsply Sirona Endodontic Suite opens at NYU College of Dentistry / There is a better way (and LVI can show you how to get there) / Safe and effective irrigation with Directa’s double-side-vented Calasept Irrigation Needle / Imprint

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Table of contents

roots
issn 2161-6558

the international C.E. magazine of

1

2017

_C.E. article
Canal preparation
and obturation

_training
Recent advances
in 3D-printed dental
replicas

_case study
Preserving
dentin and
deep cleaning

International Edition • Vol. 7 • Issue 1/2017

endodontics

[2] =>

[3] =>

editorial _ roots

The annual AAE
meeting is our time
to shine

Fred Weinstein, DMD, MRCD(C),
FICD, FACD

It’s likely that you picked up this copy of roots at AAE17, the annual session of the American Association
of Endodontists, held this year in New Orleans, and you are reading this on your flight home. That’s good,
because this issue includes many helpful articles, including information on some of the latest topics — from
cleaning and shaping to new technology used for disinfection.
If you are like me, you look forward to the AAE meeting each year, not only for the camaraderie but also
because of the knowledge that is shared among compatriots. How many of the lectures and hands-on
workshops did you attend at this year’s meeting? Which was your favorite? No matter what course or
speaker inspired you, it’s all part of the greater knowledge about our specialty.
A small part of that knowledge base is contained on the pages that follow. Chief among them is an
article by Dr. L. Stephen Buchanan, titled “Recent advances in 3D-printed dental replicas for procedural
training and board exams,” and an article by Dr. Khang T. Le, “18-month case study of a C-shaped mandibular molar: Preserving dentin and deep cleaning utilizing an innovative procedure.” There’s also a report
on the newly opened Dentsply Sirona Endodontic Suite at NYU College of Dentistry.
The centerpiece of this publication is an article by Dr. Ove A. Peters. “Canal preparation and obturation: An updated view of the two pillars of nonsurgical endodontics,” which originally appeared in AAE’s
ENDODONTICS: Colleagues for Excellence newsletter, is being made available in this issue of roots with the
permission of the AAE. By reading this article, and then taking a short online quiz at www.DTStudyClub.
com, you will gain one ADA CERP-certified C.E. credit. Remember that with roots, you can always earn C.E.
credit without lost revenue and time away from your practice.
To learn more about how you can take advantage of this C.E. opportunity, visit www.DTStudyClub.
com. You need only register at the Dental Tribune Study Club website to access these C.E. materials free of
charge. You may take the C.E. quiz after registering.
You can also access the vast library of C.E. articles published in the AAE’s clinical newsletter by visiting
www.aae.org/colleagues.
I know that taking time away from your practice to pursue C.E. credits is costly in terms of lost revenue
and time, and that is another reason roots is such a valuable publication. I hope you will enjoy this issue
and that you will take advantage of the C.E. opportunity.
As always, I welcome your comments and feedback.

Fred Weinstein, DMD, MRCD(C), FICD, FACD
Editor in Chief

roots
1
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_ 2017

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I content_ roots

page 12

page 06

page 14

I C.E. article

industry

06

20	Safe and effective irrigation with Directa’s
double-side-vented Calasept Irrigation Needle

 anal preparation and obturation:
C
An updated view of the two pillars
of nonsurgical endodontics

I about the publisher

_Ove A. Peters, DMD, MS, PHD

22

I training
12	Recent advances in 3D-printed dental
replicas for procedural training and
board exams
_L. Stephen Buchanan, DDS, FACD, FICD

1

_imprint

roots

2016

International Edition • Vol. 7 • Issue 1/2017

issn 2161-6558

the international C.E. magazine of

I case study

1

14	18-month case study of a C-shaped
mandibular molar: Preserving dentin
and deep cleaning utilizing an
innovative procedure

endodontics

2017

_C.E. article
Canal preparation
and obturation

_training
Recent advances
in 3D-printed dental
replicas

_case study
Preserving dentin and
deep cleaning

_Khang T. Le, DDS

education
17	Dentsply Sirona Endodontic Suite opens
at NYU College of Dentistry

industry education
18	There is a better way (and LVI can show
you how to get there)
_Mark Duncan, DDS, FAGD, LVIF, DICOI, FICCMO

page 17

04 I roots
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I on the cover

The EndoSafe Plus™, available from Vista Dental Products,
provides apical negative pressure irrigation. Simultaneous
irrigation and evacuation provides a continuous, controlled
flow of irrigating solutions and flushing of debris, while
minimizing the risk of apical extrusion.
(Photo/Provided by Vista Dental Products)

page 18

page 20

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[6] =>

I C.E. article_ instrumentation and obturation

Canal preparation and
obturation: An updated
view of the two pillars of
nonsurgical endodontics
Author_Ove A. Peters, DMD, MS, PHD

_c.e. credit
This article qualifies for C.E.
credit. To take the C.E. quiz, log
on to www.dtstudyclub.com.
Click on ‘C.E. articles’ and
search for this edition (Roots
C.E. Magazine — 1/2017). If
you are not registered with the
site, you will be asked to do so
before taking the quiz. You may
also access the quiz by using
the QR code below.

06 I roots
1_ 2017

_The ultimate goal of endodontic treatment
is the long-term retention in function of teeth
with pulpal or periapical pathosis. Depending on
the diagnosis, this therapy typically involves the
preparation and obturation of all root canals.
Both steps are critical to an optimal long-term
outcome. This article is intended to update
clinicians on the current understanding of
best practices in the two pillars of nonsurgical
endodontics, canal preparation and obturation,
and to highlight strategies for decision making
in both uncomplicated and more difficult endodontic cases.
Prior to initiating therapy, a clinician must
establish a diagnosis, take a thorough patient
history and conduct clinical tests. Recently, judicious use of cone-beam computed tomography
(CBCT) has augmented the clinically available
imaging modalities. Verifying the mental image
of canal anatomy goes a long way to promote
success in canal preparation. For example, a
missed canal frequently is associated with endodontic failures.1
As most maxillary molars have two canals
in the mesiobuccal root, case referral to an endodontist for microscope-supported treatment
should be considered. Endodontists are increasingly using CBCT and the operating microscope
to diagnose and treat anatomically challenging
teeth, such as those with unusual root anatomies,
congenital variants or iatrogenic alteration. The
endodontic specialist, using appropriate strategies, can achieve good outcomes even in cases
with significant challenges (Fig. 1).

_Preparation of the endodontic space
The goal of canal preparation is to provide adequate access for disinfecting solutions without
making major preparation errors such as perforations, canal transportations, instrument fractures
or unnecessary removal of tooth structure. The
introduction of nickel-titanium (NiTi) instruments to
endodontics almost two decades ago2 has resulted in
dramatic improvements for successful canal preparation for generalists and specialists. Today there are
more than 50 canal preparation systems; however,
not every instrument system is suitable for every
clinician and not all cases lend themselves to rotary
preparation.
Several key factors have added versatility in this
regard, for example, the emergence of special designs
such as orifice shapers and mechanized glide path
files. Another recent development is the application of heat treatment to NiTi alloy, both before and
after the file is manufactured. Deeper knowledge of
metallurgical properties is desirable for clinicians
who want to capitalize on these new alloys. Finally,
more recent strategies such as minimally invasive
endodontics have emerged.3

_Basic nickel titanium metallurgy
What makes NiTi so special? It is highly resistant
to corrosion and, more importantly, it is highly elastic
and fracture-resistant. NiTi exists reversibly in two
conformations, martensite and austenite, depending
on external tension and ambient temperature. While
steel allows 3 percent elastic deformation, NiTi in the

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C.E. article_ instrumentation and obturation

austenitic form can withstand deformations of up
to 7 percent without permanent damage or plastic
deformation.4 Knowing this is critical for rotary endodontic instruments for two reasons. First, during
preparation of curved canals, forces between the
canal wall and abrading instruments are smaller with
more elastic instruments, hence less preparation errors are likely to occur.
Second, rotation in curved canals will bend instruments once per rotation, which ultimately will lead
to work hardening and brittle fracture, also known as
cyclic fatigue. Steel can withstand up to 20 complete
bending cycles, while NiTi can endure up to 1,000
cycles.4
Recently manufacturers have learned to produce
NiTi instruments that are in the martensitic state and
even more flexible than previous files. Figure 2 shows
how instrument conditions (austenite vs. martensite) are determined in the testing laboratory, using
prescribed heating and cooling cycles.5 Heat-treated
files with high martensite content typically do not
have a silver metallic shade but are colored due to an
oxide layer, such as gold or blue.
It is important to note that CM files frequently
deform; however, with a delicate touch, cutting is adequate and often even superior to conventional NiTi
instruments.6 It is imperative for clinicians to retrain
themselves prior to using these new instruments to
avoid excessive deformation and subsequent instrument fracture.

_Preparation strategies
Experimental and clinical evidence suggests
that the use of NiTi instruments combined with
rotary movement results in improved preparation
quality. Specifically, the incidence of gross preparation errors is greatly reduced.7 Canals with wide
oval or ribbon-shaped cross-sections present difficulties for rotary instruments and strategies such
as circumferential filing and ultrasonics should be
used in those canals.
Studies found that oscillating instruments recommended for these canal types did not perform as
well,8 particularly in curved canals. Specific instruments developed to address these challenges include
the Self-Adjusting File (SAF) System (ReDentNOVA,
Raana, Israel), TRUShape® (Dentsply Sirona, Tulsa,
Okla.) and XP Endo® (Brasseler, Savannah, Ga.). However, there is no direct clinical evidence that these
instruments lead to better outcomes.
Canal transportation with contemporary NiTi
rotaries, measured as undesirable changes of the
canal center seen in cross-sections of natural teeth,
is usually very small. This indicates that canal walls
are not excessively thinned and apical canal paths
are only minimally straightened (Fig. 1), even when

Fig. 1

preparing curved root canals. While preparation
usually removes dentin somewhat preferentially
toward the outside of the curvature,9 current NiTi
instruments, including reciprocating files, can
enlarge the canal path safely while minimizing
procedural errors.
Almost all current rotaries are non-landed, meaning they have sharp cutting edges, and they can be
used in lateral action toward a specific point on the
perimeter. This “brushing” action allows the clinician
to actively change canal paths away from the furcation in the coronal and middle thirds of the root canal10 but may create apical canal straightening when
taken beyond the apical constriction. Circumferential
engagement of canal walls by active instruments
may lead to a threading-in effect, but contemporary
rotaries are designed with variable pitch and helical
angle to counteract this tendency.
An important design element for all contemporary rotaries is a passive, non-cutting tip that guides
the cutting planes to allow for more evenly distributed dentin removal. Rotaries with cutting, active
tips such as dedicated retreatment files should be
used with caution to avoid preparation errors.

Fig. 1_Root canal treatment of
tooth #3 diagnosed with pulp
necrosis and acute apical
periodontitis. The mesiobuccal
root has a significant curve and
two canals with separate apical
foramina. Case courtesy of
Dr. Jeffrey Kawilarang.
(Photos/Provided by American
Association of Endodontists)

_NiTi instrument usage
As a general rule, flexible instruments are not very
resistant to torsional load but are resistant to cyclic
fatigue. Conversely, more rigid files can withstand
more torque but are susceptible to fatigue. The
greater the amount and the more peripheral the
distribution of metal in the cross section, the stiffer
the file.11 Therefore, a file with greater taper and
larger diameter is more susceptible to fatigue failure;

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I C.E. article_ instrumentation and obturation

Fig. 2

Fig. 2_Behavior of controlledmemory nickel-titanium rotaries
compared with standard
instruments. Shown are data from
Typhoon Differential scanning
calorimetry, which document the
transition between austenite and
martensite at about 5 degrees C
for standard NiTi and at about
25 degrees C for controlled-memory
(CM) alloy (A). At room temperature,
this results in a drastically increased
fatigue lifespan (B).Image A modified
and reprinted with permission from
Shen et al.J Endod 2011;
37:1566-1571.

08 I roots
1_ 2017

moreover, a canal curvature that is more coronal is
more vulnerable to file fracture.
Instrument handling has been shown to be associated with file fracture. For example, a lower rotational speed (~250 rpm) results in delayed build-up
of fatigue12 and reduced incidence of taper lock.13
Material imperfections such as microfractures and
milling marks are believed to act as fracture initiation
sites.14 Such surface imperfections after manufacturing can be removed by electropolishing but it is
unclear if this process extends fatigue life.15
Manufacturers’ recommendations stress that rotaries should be advanced with very light pressure;
however, the recommendations differ with regard
to the way the instruments are moved. A typical
recommendation is to move the instrument into the
canal gently in an in-and-out motion for three to
four cycles, directed away from the furcation, then
withdraw to clean the flutes.
It is difficult to determine exactly the apically
exerted force in the clinical setting; experiments
have suggested that forces start at about 1 Newton
(N) and range up to 5 N.16 Precise torque limits have
been discussed as a means to reduce failure. Most
clinicians use torque-controlled motors, which are
based on presetting a maximum current for a DC
electric motor.
To reduce friction, manufacturers often recommend the use of gel-based lubricants in dentin;
however, such lubricants have not been shown to
be beneficial and actually did increase torque for
radial-landed ProFile® instruments.17 Therefore, it is
recommended to flood the canal system with sodium
hypochlorite (NaOCl) during the use of rotaries. The
best way to do this is to create an access cavity that
can act as a reservoir (Fig. 3).

There are several concerns about reusing NiTi
instruments. The effectiveness of disinfection procedures is not clear. It has been shown that protein particles cannot completely be removed from machined
nickel-titanium surfaces.18 Moreover, it is clear that
with additional usage, the chance for instrument
fracture increases. Current recommendations advise
that clinicians are judicious when reusing rotary
instruments as there is no conclusive evidence of
disease transmission occurring.
Recently, the term minimally invasive endodontics has been used to describe smaller-than-usual
apical sizes and, perhaps more importantly, an
understanding that the long-term success of root
canal-treated teeth will improve by retaining as
much dentin structure as feasible.3 The thought
process for this was the finding that most root-canal
treated teeth survive 10 years and longer.19 In studies,
the reasons cited for the extraction vary but in many
cases teeth are either fractured or non-restorable for
other reasons.20,21
In consequence, a smaller coronal dimension of
rotaries is considered while maintaining apical sizes
to support antimicrobial efficacy. There currently is
no direct clinical evidence to support this strategy
but it is clear that root fractures pose problems in
the long-term outcomes of our patients. Another
recent development is the emergence of certain
specialized rotaries, such as dedicated orifice shapers and so-called glide path files. The orifice shapers
have larger tapers, such as .08, which means that
they are not flexible and can overprepare at the
canal orifice level. Glide path files, for example
PathFiles® and ProGlider® (Dentsply Sirona), are
delicate instruments and may fracture when used
incorrectly. It is recommended to use a small K-file
(size #10) before any rotary instrumentation and to
use a delicate touch.

_Clinical results
While results from in vitro studies on rotary
systems are abundant, clinical studies on these
instruments are sparse. Comparing NiTi and stainless steel K-files, Pettiette et al.7 found less canal
transportation and fewer gross preparation errors
such as strip perforations. Subsequently, using radiographic evaluation of the same patient group, they
demonstrated better healing in the NiTi group.22 An
earlier outcome study with three rotary preparation
paradigms did not show any difference between the
three systems with an overall favorable outcome rate
of about 87 percent.23
The most consistent clinical results are obtained
when the manufacturer’s directions are followed.
While these vary by instrument, a set of common rules applies to root canal preparation. Root

[9] =>

C.E. article_ instrumentation and obturation

canal systems are best prepared in the following
sequence:
• Analysis of the specific anatomy of the case.
• Canal scouting.
• Coronal modifications.
• Negotiation to patency.
• Determination of working length.
• Glide path preparation.
• Root canal shaping to desired size.
• Gauging the foramen, apical adjustment.

_Obturation of the endodontic space
A well-shaped and cleaned canal system should
create the conditions for intact periapical tissues. On
the other hand, this root canal system is inaccessible
to the body’s immune system and therefore it cannot
combat coronal leakage. Accordingly, best practices
dictate that root canals should be filled as completely
as possible to prevent ingress of nutrients or oral microorganism. None of the established techniques for
root canal filling provides a definitive coronal, lateral
and apical seal.24

_Basic strategies in root canal obturation
Ideally, root canal fillings should seal all foramina
leading to the periodontium, be without voids, adapt
to the instrumented canal walls and end at working
length. There are various acceptable materials and
techniques to obturate root canal systems, including:
• Sealer (cement/paste/resin) only.
• Sealer and a single cone of a stiff or flexible core
material.
• Sealer coating combined with cold compaction
of core materials.
• Sealer coating combined with warm compaction of core materials.
• Sealer coating combined with carrier-based
core materials.
Several of these techniques have shown comparable success rates regarding apical bone fill or
healing of periradicular lesions, so a clinician may
choose from a variety of techniques and approaches
that works best for him or her. Existing research
directs clinicians toward preparation and disinfection of the root canal as the single most important
factor in the treatment of endodontic pathosis, and
no particular sealing technique can claim superior
healing success.25

_Current developments in root canal
obturation materials
After the introduction of MTA (mineral trioxide
aggregate) as a material for perforation repair and

Fig. 3

apical surgery more than two decades ago, materials
with similar bioactive properties now are available as
root canal sealers. Bioceramic root canal cement (BC
Sealer™, Brasseler) has clinically acceptable radiopacity and flow.26 Moreover, it is well-tolerated in cell
culture experiments.27 However, there is no clinical
evidence that using this cement leads to better outcomes. In fact, most research has indicated the type
of cement used has comparatively little impact.28
In contemporary practice, heat generators are
used to plasticize gutta-percha. Additionally, cordless heating devices are available. Another recent
addition is a carrier-based material, Guttacore®
(Dentsply Sirona), which uses modified gutta-percha
materials instead of plastic as its base. Early data indicate that obturation with this new material is similar
to warm vertical compaction or lateral compaction.29

Fig. 3_Root canal treatment of
tooth #19 with four canals diagnosed
with irreversible pulpitis and acute
apical periodontitis. A second canal
in the distal root of a mandibular
molar is not infrequent. Note
multiple apical foramina in both the
mesial and the distal apices. Prior
to temporization, the orifices were
protected with a barrier of lightcuring glass ionomer. Case courtesy
of Dr. Paymon Bahrami.

_Practical aspects of obturation
The main steps in the sequence of root canal
obturation are:
• Choosing a technique and timing the obturation.
• Selecting master cones.
• Canal drying, sealer application.

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I C.E. article_ instrumentation and obturation

Fig. 4

Fig. 4_Root canal treatment of
tooth #15 with four canals,
diagnosed with irreversible pulpitis
and acute apical periodontitis. The
tooth was restored with a crown
immediately after finalizing the root
canal treatment. Case courtesy of
Dr. Reza Hamid.

10 I roots
1_ 2017

• Filling the apical portion (lateral and vertical
compaction).
• Completing the fill.
• Assessing the quality of the fill.
The root canal system should be assessed before
choosing an obturation technique. In the presence of
open apices or procedural errors such as apical zipping and also for teeth with apices in close proximity
to the mandibular canal, there is significant potential
for overfills. In order to avoid such mishaps, these
cases may be better obturated with cold lateral condensation to avoid overfilling, or in some cases, MTA
may be placed as a barrier.
In general, canals should be filled only when
there are no symptoms of acute apical periodontitis or an apical abscess, such as significant pain
on percussion or not dryable due to secretion into
the canal. Gutta-percha cones first should be disinfected by submerging them in an NaOCl solution
for about 60 seconds.
In addition to a solid filler such as gutta-percha,
a sealer or cement should be used. Most sealers are
toxic in the freshly mixed state, but this toxicity is
reduced after setting. When in contact with tissues
and tissue fluids, zinc oxide eugenol-based sealers
are absorbable while resin-based materials typically
are not absorbed.30 Some by-products of sealers may
adversely affect and delay healing. Therefore, sealers
should not be routinely extruded into the periradicular tissues.
The appropriate amount of sealer is then deposited into the canal system. This may be done
using a lentulo spiral, a K-file or the master cones
themselves; each method is acceptable, provided

that an appropriate amount of sealer is deposited. If
the master cones are the carrier for the sealer, they
should be removed and inspected for a complete
coating with sealer and then replaced in the canal.
The master cones are placed close to working
length using a slight pumping motion to allow
trapped air and the excess sealer to flow in a coronal
direction. The marking on the cone should be close
to the coronal reference point for working length
determination. For lateral compaction, a preselected
finger spreader is then slowly inserted alongside
the master cone to the marked length and held with
measured apical pressure for about 10 seconds. During this procedure, the master cone is pushed laterally
and vertically as the clinician feels the compression
of the gutta-percha. Rotation of the spreader around
its axis will disengage it from the gutta-percha mass
and facilitate removal from the canal.
The space created by the spreader is filled by
inserting a small, lightly sealer-coated accessory
gutta-percha cone. Using auxiliary cones larger than
the taper of the spreader will produce voids or sealer
pools in the filling and should be avoided. The procedure is repeated by inserting several gutta-percha
cones until the entire canal is filled.
For vertical compaction, electrically heated pluggers are used to melt a master cone fitted to length.
Tapered gutta-percha cones optimize the hydraulic
forces that arise during compaction of softened
gutta-percha with pluggers of a similar taper. After
ﬁtting the master cone as before, different hand
pluggers and heated pluggers are placed into the root
canal to verify a ﬁt to within 5 to 7 mm of the apical
constriction.
For both lateral and vertical compaction the
gutta-percha mass in each canal should end about
1 mm below the pulpal floor, leaving a small dimple.
In cases where placement of a post is planned, guttapercha is confined to the apical 5 mm.31 All root
canals that do not receive a post may be protected
with an orifice barrier (Fig. 3) to protect from leakage prior to placement of a definitive restoration.32
This has been shown to promote healing of apical
periodontitis.33 Materials that are suitable for such a
barrier include light-curing glass ionomers, flowable
composites or fissure sealants. In order to facilitate
retreatment if necessary, such a barrier should be
thin so that the gutta-percha fill is just visible.

_Radiographic appearance of filled root
canal systems
Prepared and filled canals should demonstrate a
homogenous radiopaque appearance, free of voids
and filled to working length. The fill should approximate canal walls and extend as much as possible into
canal irregularities such as an isthmus or a c-shaped

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C.E. article_ instrumentation and obturation

canal system. This is difficult to achieve clinically and
frequently requires the clinician to use a thermoplastic obturation technique. This complicated procedure
may benefit from the use of the dental operating
microscope.
Other anatomical spaces that may be filled include
accessory canals that are most common in the apical
root third (Fig. 3, mesial and distal root) but may be
found in other locations such as the furcation. It has
been well established that accessory anatomy may
contribute to periapical periodontitis34 but clinical
experience suggests the role of accessory anatomy
in causing bone resorption is comparatively small.
Indeed, it appears that filling accessory canals is not
predictable and not per se a prerequisite for success.35
In order to avoid overextension of root filling
material into the periapical tissue, specifically in the
mandibular canal, it is recommended to accurately
determine working length to prevent destruction
of the apical constriction. For infected root canal
systems, it seems that the best healing results are
achieved when the working length is slightly short
of the tip of the root, as visible on a radiograph.25, 36
Determination of apical canal anatomy is often
difficult. It may be appropriate for second mandibular
molars that are in close proximity to the mandibular
canal to be referred to a specialist. Overfills are not
only an impediment to healing but in the worst case
can be associated with permanent nerve damage. In
general, undesirable and uncorrectable outcomes of
root canal treatment, identifiable on the final radiograph, include:
• Excessive dentin removal during access and
instrumentation.
• Preparation errors such as perforation, ledge
formation and apical zipping.
• Presence of an instrument fragment in not fully
disinfected canals.
• Obturation material overfill and overextension.
Each of these outcomes must be documented and
the patient notified as they may reduce the likelihood
of a successful outcome. In cases such as par- or
dysesthesia after an overfill, immediate referral to a
surgeon is indicated.

_Summary and conclusions
Root canal preparation with contemporary instruments is a predictable procedure in most cases
for a well-trained clinician following established
guidelines. Cases with a recognized high degree of
difficulty are best referred to an endodontist. While
many cases can be treated successfully in routine
practice, the additional training, expertise and technology of endodontists is necessary in cases that are
beyond the typical spectrum. The best long-term

outcomes are obtained when a correctly planned
final restoration is placed as soon as possible after
root canal treatment is completed (Fig. 4).
Root canals may be filled through various methods, typically using a combination of a cement and
a solid filling material such as gutta-percha. The
specific obturation material used appears to have
a smaller role on outcomes. Overfills, particularly
into the area of the inferior alveolar nerve, have the
potential to permanently harm a patient. The absence
of gross errors that are associated with persistent
presence of bacterial infection and excessive dentin
removal during access and canal preparation have
the greatest impact on outcomes._
This article originally appeared in ENDODONTICS:
Colleagues for Excellence, Fall 2016. Reprinted with
permission from the American Association of Endodontists, ©2016. The AAE clinical newsletter is available at www.aae.org/colleagues.
A complete list of references is available from the
publisher and also at www.aae.org/colleagues.

_about the author

roots

Dr. Ove A. Peters was
awarded a degree in dentistry (Dr. med dent) from the
University of Kiel, Germany,
in 1990. After two years in
the Department of Neurophysiology at the University
of Kiel, he served as an
assistant professor of prosthodontics at the University
of Heidelberg, Germany,
from 1993 to 1996. Peters
received post-graduate endodontic training at Zurich University Dental School (1997-2001) and at the University of
California, San Francisco (2004-2006). He was an associate professor and head of the faculty practice in restorative
dentistry at the University of Zurich from 1996 to 2001.
Peters also earned a certificate in endodontics and MS
certificate in oral biology from UCSF and was board certified
in endodontics in 2010. He received the Louis I. Grossman
Award in 2012. Peters is currently a tenured professor and
co-chair of the Department of Endodontics at the Arthur A.
Dugoni School of Dentistry at the University of the Pacific,
San Francisco, and the director of the Advanced Euducation
Program in Endodontology. His main scientific interests
are the performance of root canal instruments assessed by
mechanical testing methods, three-dimensional imaging
and the efficacy of antimicrobial regimes in root canal treatment. More recently, he became involved in endodontic
biology and now runs a dental stem cell biology laboratory.
Peters has published more than 100 papers in peer-reviewed
journals and has lectured extensively both nationally and
internationally. He has written multiple chapters in leading
textbooks and serves on the review panels and editorial
boards of high-impact endodontic journals. He may be
contacted at opeters@pacific.edu.

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I training_ 3D-printed dental replicas

Recent advances in 3D-printed
dental replicas for procedural
training and board exams
Author_L. Stephen Buchanan, DDS, FICD, FACD

Fig. 1_3D-printed dental board
exam replica embedded in
rubber sleeve, allowing complete
standardization between candidates
and examiners for the first time,
while it eliminates the need by the
student to find acceptable extracted
teeth and for examiners to check
and approve candidate’s choices.
This sleeve fits in commonly used
typodont cavities. (Photos/Provided
by Dr. L. Stephen Buchanan)
Fig. 2_Radiograph of exam
replica after a candidate’s finished
endodontic procedure.
Fig. 3_Molar exam replica in
typodont cavity with apex locator
leads attached.
Figs. 4a, b_Practice replica with
reusable rubber sleeve. This sleeve
allows multiple inexpensive practice
sessions without the need to buy new
typodont modules, yet it delivers the
same ideal apex locator function as
the more expensive exam replicas.

_Medical and dental procedural training has
always had the severe limitation of being done on
living patients in a one-on-one preceptorship basis
unless cadavers are used. But cadavers are severely
regulated and short in supply, thus quite expensive,
as well as being biohazardous and creepy. A common
alternative, of training dentists to do implant surgery in pig jaws, allows only the most fundamental
procedures to be practiced — none of which present
doctors with the case-by-case, on-the-fly treatment
planning decisions that must be honed to empower
predictable success when tissues have been incised
and soft-tissue flaps have been reflected.
In this light, 3D-printed dental replicas offer an
amazing paradigm shift in dental procedural training. Impossible otherwise, 3D printing authentically
reproduces human anatomy in much the same way
body parts are created — through additive means —
rather than by reductive CAD/CAM milling of material blocks or by injecting material into the limited
geometry of molds. Stereo-lithography offers the
ability to re-create internal morphology just as human bodies do, layer by layer. Multi-ink printers even
allow both hard and soft tissues to be replicated in a
single training jaw.
It has been truly fortunate that we can train
dentists to do endodontic procedures in human
extracted teeth that are no longer attached to their
original owners; however we are still faced with the
random endodontic anatomy that presents as col-

lected in extracted tooth jars. With extracted teeth,
educators cannot choose the exact anatomic challenge presented to their students to satisfy a given
training objective, nor do they typically know what
is inside all of the student’s practice teeth during
a hands-on course. When we control the anatomy
that is practiced in, educators can better control the
students’ experience and further shorten their learning curve.1,2
Beyond that, when students fail to achieve their
procedural objective in an extracted tooth, there are
no do-overs, thus it is a truism that it typically takes
hundreds of endodontic procedural experiences in
extracted teeth and patients’ root canal systems before predictable competence can be achieved. Airline
pilots, astronauts, musicians, police and soldiers are
all taught with simulation exercises that allow iterative improvements in skill sets, something that has
previously been impossible in dental and medical
procedural training.
When we consider traditional methods of training health care professionals to do dangerous
procedures safely in human beings, it becomes
obvious that medical and dental education is different than almost every other endeavor to create
human competence in complex processes. Thus
3D-printed replication has and will continue to
change everything about conventional and surgical training. This article describes recent advances
beyond the printing of individual teeth for endo-

Fig. 4a

Fig. 1

Fig. 2

12 I roots
1_ 2017

Fig. 3

Fig. 4b

[13] =>

training_ 3D-printed dental replicas

Fig. 5a

Fig. 8

Fig. 5b

Fig. 9

dontic training, both in educational as well as board
exam arenas.
About two years ago, the president of a prominent
board of dental examiners asked if we could model
and print replicas that would authentically replace
extracted teeth in their exams. Because 3D-printing
allows fabrication of literally any organic or inorganic
form that can be modeled on a graphics computer, it
was obviously possible although many’s the slip between cup and lip. In these cases I follow the advice of
Richard Diebenkorn3 for any creative project. I begin
by doing research to understand the context, the art,
that has preceded my efforts. What I found was that
existing endodontic models were not anatomically
authentic — their canals were like soda straws in their
oversimplified form, they were much softer than
tooth structure when cut with high-speed handpiece
burs, and, despite claims to the contrary, they did not
work with apex locators. Over a period of two years
our design and development process resulted in
board exam testing replicas (Figs. 1-3) that had:
1. Coronal hardness very similar to natural teeth
when cut by high-speed handpieces.
2. The exact anatomy found in human teeth.
3. Apex locator function that was as accurate as
natural teeth.
4. Embedment in a rubber sleeve (with serial numbers) that fit readily available typodonts.
5. Authentic radiopacity.
That development process also inspired an inexpensive version of these exam replicas that allowed
our TrueTooth training replicas to be used in a better
simulation than with individual replicas. While the
exam replicas are expensive with milled composite/
ceramic crowns, non-reusable sleeves and unique
identification, the TrueTooth practice replicas now
have reusable split sleeves that hold them in a typodont and perform perfectly with apex locators,
allowing dental students to practice on replicas that
cost less than $15 each (Figs. 4a,b).
The other recent advance was what I call TrueJaw

Fig. 6a

Fig. 6b

Fig. 10

_References
1.

Buchanan, LS, Control the Anatomy; Control Procedural
Training-New Teaching Paradigms from 3D Printed
Procedural Training Replicas, Roots, May 2014.
Buchanan, LS, Focus On: Endondotics, Interview with
Damon Adams on the impact of 3D printing on procedural
education, Dentistry Today, Pg 2, December 2015.
Diebenkorn, R, Notes to myself: Diebenkorn’s 10 rules for
painting. Blog, Royal Academy of Arts, U.K., 3.13.15.

_about the author

Fig. 7

Fig. 11

2.0 — full-jaw replicas designed to train endodontic
residents to do periradicular surgery, including incision, ostectomy, apicoectomy, retrograde preparations and fills, bone grafting and suturing. Each upper
and lower jaw has five teeth with various periapical
lesions, some perforating the cortical plate and some
with root ends that need to be located through intact
boney structures (Figs. 5a-12).
Procedural dental education and testing will
never be the same._

roots

L. Stephen Buchanan, DDS,
FACD, FICD, is a diplomate
of the American Board of
Endodontics, a fellow of the
American and International
Colleges of Dentists and
serves as part-time faculty
to the UCLA and USC graduate endodontic programs. He
holds patents on the Endobender Plier (SybronEndo),
System-B and Continuous
Wave obturation tools and methods (SybronEndo), GT and
GTX file systems (DENTSPLY Tulsa Dental Specialties), LA
Axxess Burs (SybronEndo), and Buc ultrasonic tips (Spartan/
Obtura). Buchanan lives in Santa Barbara, Calif., where he
enjoys a practice limited to conventional and microsurgical
endodontics and dental implant surgery. He is the founder of
Dental Education Laboratories, a hands-on training facility in
Santa Barbara that he has directed for 28 years.

Fig. 12

Fig. 5a_CAD model of endodontic
surgical training replica showing PA
lesions associated with tooth #9 and
tooth #12.
Fig. 5b_3D-printed maxillary
endodontic surgical training
TrueJaw. Each jaw has five different
tooth replicas with periapical lesions,
some perforating the cortical plate
and others hidden behind intact bone
surfaces.
Fig. 6a_Buccal view CT image
of TrueJaw replica tooth #9 with
PA lesion. Note the authentic
appearance of tooth, PDL, medullary
and cortical bone.
Fig. 6b_Sagital view CT image of TJ
replica #9.
Fig. 7_Incision of rubber-like softtissue replication in preparation for
endo surgical flap.
Fig. 8_Flap replica reflected,
revealing PA lesion perforating the
cortical plate.
Fig. 9_Osseous crypt developed,
showing root end with canal.
Fig. 10_Retrograde canal
preparation with ultrasonic tip.
Fig. 11_Retrograde filling in place.
Fig. 12_Flap sutured.

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[14] =>

I case study_ GentleWave Procedure

18-month case study of a
C-shaped mandibular molar:
Preserving dentin and deep cleaning
utilizing an innovative procedure
Author_Khang T. Le, DDS, SC Endodontics, Santa Ana, Calif.

_Introduction
Complexities within the root canal system provide
intricate regions for tissue, debris and bacteria-rich
environments that remain untouched after standard
root canal treatment. When the complicated anatomies of a C-shaped canal are introduced, occurring
in about 8 percent of mandibular second molars, the
endodontic challenges for debridement and disinfection are increased.1-3 An innovative technology,
the GentleWave® Procedure (Sonendo®, Laguna
Hills, Calif.) has been shown to enhance root canal
cleaning and disinfection through advanced fluid
dynamics, acoustics and tissue dissolution chemistry
(Fig. 1).4-8 Studies have shown the GentleWave Pro-

cedure to have seven times faster tissue dissolution
than standard root canal systems and demonstrated
success rates of 97 percent at 12 months.6,9

_Background
A 47-year-old female presented with a chief
complaint of spontaneous pain and sensitivity to
cold and chewing. The patient reported a history of
hypothyroidism, but all other medical history was
unremarkable. Upon clinical examination, the mandibular second molar (#31) showed moderate sensitivity to percussion and palpation. Vitality testing
elicited a lingering response (Fig. 2a). A diagnosis of
symptomatic irreversible pulpitis and symptomatic
apical periodontitis was made.

_Methods

Fig. 1_The GentleWave Procedure
(Image/Provided by Sonendo)

14 I roots
1_ 2017

Fig. 1

Following conservative endodontic access, examination of the pulp chamber floor revealed a
C-shaped canal. To preserve tooth structure, orifice
openers were not utilized. Two file paths were created to an apical diameter of #20 merely to facilitate
a fluid and obturation path. This preservation of
dentin is crucial, as clinical success in endodontics
has been correlated to the maintenance of original
canal shape.10 While excessive apical enlargement
may lead to complications like apical transportation,
ledges and instrument separation, it also has the
potential to weaken the tooth, thereby increasing the
likelihood of root fractures.11-13
The GentleWave System was utilized to remove
pulp tissue remnants, debris, smear layer and bacteria
from the entire root canal system.5-8 The GentleWave
Procedure was the endodontic treatment modality
of choice for this case, due to its ability to thoroughly

[15] =>

[16] =>

I case study_ GentleWave Procedure
Figs. 2a-d_Radiographs:
a) Pre-GentleWave Procedure;
b) Post-GentleWave Procedure;
c) 12-month recall; and
d) 18-month recall. (Images/
Provided by Dr. Khang Le)
Figs. 3a-d_CBCT:
a-b) Post-GentleWave
Procedure; and
c-d) 12-month recall.

Fig. 2a

Fig. 2c

Fig. 2b

_Results
While post-procedure radiographs show the
C-shaped anatomy, the cone-beam computed tomography (CBCT) images highlight the complex
anatomy of the C-shaped canal, the uninstrumented
webbing and a periapical lesion that are not visualized upon radiography (Figs. 2b, 3a and 3b). Studies
report CBCT imaging is more sensitive in detection
of periapical lesions than radiography, even in cases
diagnosed with irreversible pulpitis.17-19 Clinical, radiographic and CBCT analysis was completed at the
12-month recall. The tooth was asymptomatic, and
the periapical lesion, previously visible on CBCT, had
healed (Figs. 2c, 3c and 3d). A final recall was completed 18 months post-procedure. The patient continued to be asymptomatic, and radiographic assessment revealed normal periradicular tissue (Fig 2d).

_Discussion
The challenge of C-shaped canals is the webbing
and ribbon-like structures throughout the root system,
creating small areas and recesses for tissue, debris and
bacteria to remain.1,20 This case report portrays the

1_ 2017

Fig. 3b

Fig. 3c

Fig. 3d

Fig. 2d

clean and disinfect the entire root canal system
without removing excessive dentin. The canals were
subsequently dried with paper points and obturated
using a warm vertical compaction technique with
gutta-percha and a resin-based sealer. A coronal seal
was immediately achieved by restoring the access
cavity with composite build-up.
Post-operative radiographic analysis revealed the
C-shaped anatomy (Fig. 2b). It should be noted that a
major cause for endodontic failure is the inability to
locate and treat all root canal anatomy.14-15 Without
adequate debridement, successful obturation would
not be possible. As obturation of the entire root canal
system is an indication of success for the endodontic
cleaning and debridement process, the ability to
clean and then obturate all of the root canal system,
as in this case report, is crucial to a successful endodontic procedure.16

16 I roots

Fig. 3a

complex anatomy associated within the C-shaped
canal, yet the standard root canal therapy protocol that
is associated with a high rate of procedural errors was
bypassed in favor of the innovative GentleWave Procedure.21-24 The case revealed normal periradicular tissue
and no clinical signs or symptoms at both the 12- and
18-month recalls. This case report demonstrates the
ability of the GentleWave Procedure to clean and disinfect C-shaped mandibular molars in a single visit while
conserving natural tooth structure and decreasing the
chance of intra-procedure complications as seen in
standard endodontic treatment._
Disclosure: None. A list of references is available
from the publisher.

_about the author

roots

Dr. Khang Le earned his
doctor of dental surgery
degree from the University of Colorado School of
Dentistry in 1991. He was
commissioned as a dental
officer in the United States
Navy in 1994 and proudly
served for 11 years. In 2002,
he received a certificate of
advanced clinical programs
in general dentistry from the
Naval Dental Center Southwest, San Diego. He went on to
receive his endodontic certification from the Herman Ostrow
School of Dentistry at the University of Southern California in
2008. He serves as part-time faculty for the Advanced Endodontics Program at the Herman Ostrow School of Dentistry,
University of Southern California. He is an active member
of the American Association of Endodontists, the American
Dental Association, the California Dental Association and
the Orange County Dental Society. He may be contacted at
Khangle.3588@yahoo.com.

[17] =>

education_ NYU College of Dentistry

Dentsply Sirona Endodontic Suite
opens at NYU College of Dentistry
Author_Dentsply Sirona staff
_On Thursday, Nov. 17, 2016, NYU College of Dentistry (NYU Dentistry) celebrated the culmination of a
goal set years earlier with a ribbon-cutting ceremony
for the opening of the Dentsply Sirona Endodontic
Suite. The new clinical suite, which employs the most
advanced educational and patient care technologies available, was made possible by a partnership
between NYU Dentistry and Dentsply Sirona, a
manufacturer of professional dental products and
technologies.
“Today,” said Dr. Charles N. Bertolami, Herman
Robert Fox Dean of NYU Dentistry, “NYU has the
most sophisticated endodontic suite in the nation,
ensuring our ability to provide the finest endodontic education in an environment that reflects truly
patient-centered care. And it could never, ever have
happened without Dentsply Sirona.”
Dr. Asgeir Sigurdsson, associate professor and
chair of NYU’s Dr. Ignatius N. and Sally Quartararo
Department of Endodontics, expressed his appreciation to both Dentsply Sirona and the college’s leadership team for “making possible this outstanding
facility.”
“For an endodontics department chair,” Sigurdsson said, “it is a dream come true.”
Speaking on behalf of New York University, NYU
President Andrew Hamilton said: “Thanks to Dentsply
Sirona and its partnership with the College of Dentistry, we have been able to create this beautiful and
most advanced facility of its kind. Just one of the new
treatment centers would be impressive, that there
are 37 of them is remarkable, and that they are all in
the same location and interconnected is even more
so. NYU thanks Dentsply Sirona from the bottom of
our hearts for the remarkable contribution that this
new facility makes to the College of Dentistry and to
our students’ education. It is wonderful to know that
the future endodontists we are training will have a
positive impact on the lives of our patients and on
our community because of the splendid environment
they now have in which to learn.”
NYU Executive Vice President for Health Robert
Berne said: “At NYU, the scarcest commodity is space.
The Dentsply Sirona Endodontic Suite is a magnificent example of a brilliant use of space. It is the
lodestar for future renovation projects at NYU, the
one that people will look to again and again, and it is a
major contribution to the education of our students.”

Dean Bertolami expressed both the college’s and
his personal appreciation to Bret W. Wise, executive
chairman of the board of Dentsply Sirona, noting
that when the college approached what was then
Dentsply International last spring to propose a partnership on behalf of the renovation, the company
was in the midst of a complex, international merger
with Sirona Dental Systems. Nevertheless, Bertolami
said, Wise immediately indicated his support and as
soon as the merger was completed, renovation of the
existing clinic began.
Wise said: “This was the first project undertaken by
the newly merged Dentsply Sirona and represents our
commitment to research, product development and
clinical education. Now, one of the best departments
of endodontics has the most modern clinical suite.
With this new facility, the standard has been set, and
together we’ve created an unparalleled environment
for research and clinical education. Dentsply Sirona
is grateful for this opportunity to collaborate with
NYU to advance dentistry and improve oral health.”
Dr. Mark Wolff, the college’s associate dean for
development, noted that the effort to renovate the
endodontic facility had been years in the making,
but once the partnership with Dentsply Sirona was
underway, the entire renovation was completed in
just three months, making it a “fitting testimony to
the powerful synergy that can occur when academia
and industry partner on behalf of a shared goal.”
A video of the ribbon-cutting ceremony is available online, at https://youtu.be/NhT5UIEJZ60._

A new clinical suite at NYU College of
Dentistry features a fully integrated
computer network with best-practice
case management software; a fully
equipped, state-of-the-art surgical
suite with 37 new treatment units;
intraoral digital X-ray stations;
state-of-the-art endodontic motors;
ultrasonic units; intraoral sensors;
and a cone beam computerized
tomography (CBCT) scanner, utilizing
state-of-the-art scanning technology
to produce 3-D images of teeth, soft
tissue, nerve pathways and bone in a
single scan. In front from left:
Dr. Teresa A. Dolan, vice president
and chief clinical officer, Dentsply
Sirona; Dr. Asgeir Sigurdsson,
associate professor and chair
of NYU’s Dr. Ignatius N. and
Sally Quartararo Department of
Endodontics; Jennie Hamilton;
Andrew Hamilton, president of NYU;
Bret W. Wise, executive chairman
of the board, Dentsply Sirona; and
Robert Berne, NYU executive vice
president for health. (Photo/Provided
by Dentsply Sirona)

roots
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_ 2017

[18] =>

I industry education_ LVI

There is a better way
(and LVI can show you
how to get there)
Author_Mark Duncan, DDS, FAGD, LVIF, DICOI, FICCMO, Clinical Director, LVI

The Las Vegas Institute for Advanced
Dental Studies. (Photo/Sierra
Rendon, Dental Tribune)

18 I roots
1_ 2017

_You know how those days go — all morning long,
it felt like you were struggling to keep on track with
the schedule. Your team is frustrated because they
haven’t had their full hour lunch more than one day
a week in as long as they can remember. You walked
by the sterilization room 15 minutes ago, and it sure
sounded like they were complaining to each other
because you said to work in that emergency, and they
were struggling to figure out how to pick up their kid
from daycare on time. Again.
You want them to enjoy working here, but you
have to be able to pay the bills. And your best assistant
asked you again if she can have that raise you have
been promising her. Don’t they understand?
Today will be another day of three chairs and
patient after patient asking you questions about
treatment, all eager to get started with getting their
mouth fixed, but yet you still won’t see any of them
show up on the schedule. They said they wanted to
do the work, but for some reason, they never seem to
come back and do it.
They say insurance doesn’t cover it, or they ask for
a pre-determination. Too bad they don’t know the
pre-determination doesn’t mean much.

Today, you have 27 patients on your schedule and
will work your butt off and still not have a chance to
pee. It looks like you should be able to be done by 5,
but today will finish worse than yesterday.
It feels like half of your patients are crankier than
you are, and your team isn’t really talking to you
today, and you know when you get home, all you will
want to do is go to sleep and wake up on Saturday —
except it’s still Tuesday!
It doesn’t make sense — you have taken C.E. courses
every time they come to town. The new insurance plan
was supposed to make things easier. You bought a
bunch of new equipment to save money on taxes — of
course now you have to pay for it every month — but
why does it seem like the harder you work, the further
behind you get? There has to be a simple reason.
Well, it turns out there actually is — and it’s something that you learned when you were about 5! Do
unto others. More specifically, build systems in your
office so that you can treat your patients the way you
would want to be treated — comprehensively and with
exceptional information to make good decisions — and
produce a consistent experience time after time.
While doing that, add exceptional care — esthetic
adhesive excellence like you see in the journals. But how?
Well, the answer happens to be the foundation that LVI
was built upon — building the excellence in a patientcentered practice. And the programs at LVI have been
teaching clinical excellence and communication and
business systems for almost 20 years to help doctors
do a better job of not only seeing the patient but, more
importantly, connecting with them. Two decades of not
only communication but comprehensive diagnosis and
clinical excellence. As a result, the doctors at LVI have a
statistically higher professional satisfaction and income.
Isn’t it time you go find out what they are doing
differently? Yes. Yes it is — and congratulations on the
journey you are about to start._

[19] =>

[20] =>

I industry_ Directa

Safe and effective irrigation with
Directa’s double-side-vented
Calasept Irrigation Needle
Author_ Directa staff

Calasept Irrigation Needles
(Photo/Provided by Directa)

20 I roots
1_ 2017

_Dual-side Calasept Irrigation Needles are vented
for irrigation during root canal therapy. These highquality, double-side-vented, luer-lock irrigation needles will provide for safe and efficient irrigation when
performing endodontic treatments, according to
Directa, the company behind the product.
Calasept Irrigation Needles optimize the cleaning of canals, creating a “swirl-effect.” This will give
an effective and safe irrigation when performing
an endo treatment. Calasept irrigation needles are
available in a container packed box of 40 needles;
choose 27g or 31g. Both sizes are bendable and have
a luer-lock hub.
Directa’s dedicated goal with the development
and production of Calasept products has made the
Calasept brand a reliable line with the prime focus

to facilitate and simplify the root canal treatment
with innovative solutions for the dental practitioner, according to the company.
In 2015, Directa incorporated all Nordiska Dental’s non-amalgam products in its growing product
line, including the well-known Calasept Endoline.
Calasept is a well-known brand of products from
calcium hydroxide paste for temporary root fillings
to a complete assortment of liquids for effective
irrigation of root canals. It is a range of products for
the proper treatment of root canals by any clinic,
general practitioners and endodontic specialists.
Contact your local dealer for more information
and to order the Calasept Endoline. More product information is available online, at http://directadental.
se/products/calasept._

[21] =>

[22] =>

about the publisher _ imprint

roots

the international C.E. magazine of endodontics

U.S. Headquarters
Tribune America
116 West 23rd Street, Ste. 500
New York, NY 10011
Tel.: (212) 244-7181
Fax: (212) 244-7185
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Officer
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k.colker@dental-tribune.com

Roots Managing Editor
Fred Michmershuizen
f.michmershuizen
@dental-tribune.com
Managing Editor
Sierra Rendon
s.rendon@dental-tribune.com
Managing Editor
Robert Selleck
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Leerol Colquhoun
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Feedback & General Inquiries
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Editorial Board

Marcia Martins Marques, Leonardo
Silberman, Emina Ibrahimi, Igor Cernavin,
Daniel Heysselaer, Roeland de Moor, Julia
Kamenova, T. Dostalova, Christliebe Pasini,
Peter Steen Hansen, Aisha Sultan, Ahmed
A Hassan, Marita Luomanen, Patrick Maher,
Marie France Bertrand, Frederic Gaultier,
Antonis Kallis, Dimitris Strakas, Kenneth Luk,
Mukul Jain, Reza Fekrazad, Sharonit
Sahar-Helft, Lajos Gaspar, Paolo Vescovi,
Marina Vitale, Carlo Fornaini, Kenji Yoshida,
Hideaki Suda, Ki-Suk Kim, Liang Ling Seow,
Shaymant Singh Makhan, Enrique Trevino,
Ahmed Kabir, Blanca de Grande, José Correia
de Campos, Carmen Todea, Saleh Ghabban
Stephen Hsu, Antoni Espana Tost, Josep
Arnabat, Ahmed Abdullah, Boris Gaspirc,
Peter Fahlstedt, Claes Larsson, Michel Vock,
Hsin-Cheng Liu, Sajee Sattayut, Ferda Tasar,
Sevil Gurgan, Cem Sener, Christopher Mercer,
Valentin Preve, Ali Obeidi, Anna-Maria
Yannikou, Suchetan Pradhan, Ryan Seto, Joyce
Fong, Ingmar Ingenegeren, Peter Kleemann,
Iris Brader, Masoud Mojahedi, Gerd Volland,
Gabriele Schindler, Ralf Borchers, Stefan
Grümer, Joachim Schiffer, Detlef Klotz,
Herbert Deppe, Friedrich Lampert, Jörg
Meister, Rene Franzen, Andreas Braun, Sabine
Sennhenn-Kirchner, Siegfried Jänicke, Olaf
Oberhofer and Thorsten Kleinert

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All submissions to the editorial department are understood to be the original work of the author, meaning that he or she is the sole copyright
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Tribune America does not accept the submission of unsolicited books and manuscripts in printed or electronic form and such items will
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Tribune America strives to maintain the utmost accuracy in its clinical articles. If you find a factual error or content that requires clarification, please contact Group Editor Kristine Colker at k.colker@dental-tribune.com. Opinions expressed by authors are their own and may
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22 I roots
1_ 2017

[23] =>

[24] =>

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[cover] => roots C.E. No. 1, 2017

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Table of contents

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