roots international No. 4, 2012

Cover / Editorial / Content / Invasive cervical resorption (ICR): A description - diagnosis and discussion of optional management —A review of four long-term cases / Fluid dynamics of syringebased irrigation to optimise anti-biofilm efficacy in root-canal disinfection / Irrigation for the root canal and nothing but the root canal / Endodontic management of a hypertaurodontic maxillary first molar— A case report with a two-year follow-up / VDW Motors produced in Tuscany - Italy / International Events / Submission guidelines / Imprint

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Table of contents

issn 2193-4673

roots
international magazine of

Vol. 8 • Issue 4/2012

endodontology

4

2012

| CE article
Invasive cervical resorption (ICR):
A description, diagnosis and
discussion of optional management

| case report
Iatrogenic errors before and after
non-surgical root-canal treatment

| research
Fluid dynamics of syringe-based irrigation
to optimise anti-biofilm efficacy
in root-canal disinfection

[2] => RO0110_01_Titel

Dental Tribune for iPad –
Your weekly news selection
Our editors select the best articles and videos from around the world for you
every week. Create your personal edition in your preferred language.

ipad.dental-tribune.com

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editorial _ roots

Interdisciplinary dentistry:
An absolute essential
_We are fortunate to live in a society in which we have access to comprehensive health care and
in which the level of dental care is considered among the best in the world. Unfortunately, this is not
the case for countless other regions in the world.
Dr Gary Glassman

In an attempt to pay it forward, I have for many years now been doing charitable work for the
people of Jamaica, in addition to teaching the local dentists there how to provide proper endodontic
care to their patients. Recently, a new dental school was constructed at the University of Technology
in Kingston, Jamaica, and I was appointed Adjunct Professor of Dentistry and was asked to construct
an endodontic programme, which will produce its first graduates in 2015. Following the graduation of
these well-trained individuals, for the very first time, the 2.6 million residents of Jamaica will finally
have accessible to them the number of dentists per capita that is required.
This past weekend I had the good fortune to return to Kingston and speak at the Rosalie Warpeha
Caribbean Institute for Strategic Planning and Research in Oral Health.
I spent the weekend with a restorative dentist, an oral radiologist, a cosmetic dentist, an orthodontist, an oral pathologist and a paediatric dentist. What started out as social events quickly became
brainstorming sessions, during which we all soon realised how integrated all disciplines of dentistry
need to be but are unfortunately lacking in many respects.
As specialists, we tend to pigeonhole ourselves into our specific areas of expertise and often lose
perspective, unable to see the forest for the trees. Discussions of horizontal and vertical integration in
dental school curricula soon became a topic of total agreement among our esteemed colleagues. A
continuum of integration through case learning is both beneficial and essential. This allows students
to be capable of using their acquired foundational knowledge to approach subject matter with critical
thinking skills.
Case-based teaching has a long tradition in medicine, nursing, law and many dental programmes.
It is an important method of distilling the basic knowledge learnt in texts and lectures and applying it
to a patient in a practical manner. As practising dentists, many of us were not exposed to this type of
learning, and were left alone with the skills that we acquired in dental school to figure it out on our
own.
Through properly structured continuing education programmes, we can return to the roots of
education and combine our knowledge in an interdisciplinary manner by conferring intimately with
members of other specialties, through panel discussions and case presentations. By approaching
learning in this capacity, all of our patients in all of our respective countries will benefit from
continued oral health, with successes that will be enjoyed at levels never seen before.

Dr Gary Glassman
Doctor of Dental Surgery
Fellow of Royal College of Dentists of Canada

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I content _ roots

page 6

I editorial
03

page 18

page 22

I special topic

Interdisciplinary dentistry: An absolute essential

32

| Dr Gary Glassman

Irrigation for the root canal and nothing but the root
canal
| Dr Philippe Sleiman

I CE article
06

Invasive cervical resorption (ICR): A description,
diagnosis and discussion of optional management—
A review of four long-term cases

I industry news
38

VDW Motors produced in Tuscany, Italy
| VDW

| John J. Stropko

I meetings
I case report
40
18

Iatrogenic errors before and after non-surgical
root-canal treatment
| Dr Rafaël Michiels

34

Endodontic management of a hypertaurodontic
maxillary first molar—A case report with a two-year
follow-up

International Events

I about the publisher
41
42

| submission guidelines
| imprint

| Drs Jojo Kottoor & Dr Anil Kishen

I research
22

Fluid dynamics of syringe-based irrigation to optimise
anti-biofilm efficacy in root-canal disinfection
| Dr Christos Boutsioukis et. al.

Cover image courtesy of Bisico, www.bisico.fr

page 32

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page 38

page 40

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I CE article _ invasive cervical resorption

Invasive cervical resorption (ICR):
A description, diagnosis and
discussion of optional management
—A review of four long-term cases
Author_ John J. Stropko, USA

roots

_ce credit

By reading this article and then taking a short online quiz, you will gain
one ADA CERP CE credit. To take the CE quiz, visit www.dtstudyclub.com.
The quiz is free for subscribers, who will be sent an access code.
Please write support@dtstudyclub.com if you don’t receive it.
Non subscribers may take the quiz for a $20 fee.

_Abstract
The external resorptive process of the permanent
dentition referred to in this article has been given
several different terms over the years, so therefore
some confusion exists. Just a few popular labels are
extra-canal invasive resorption (ECIR), invasive cervical resorption (ICR), external cervical resorption (ECR),

Trauma
Intracoronal bleaching

Potential predisposing factor

Surgery
Orthodontocs
Periodontics
Bruxism

Sole factor
Additional factors

Delayed eruption
Developmental defects

Restoration

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I will present treatment of four cases—two Class 2
cases, one Class 3 and a Class 4—in an attempt to share
some experiences, both good and bad, over the years
when dealing with ICR. Hopefully, the following
article will be successful in removing some barriers
that may currently prevent the doctor from accepting
the challenge presented by the next case of ICR.

_Aetiology of invasive cervical resorption

Interproximal stripping

Fig. 1_Invasive cervical resorption:
Distribution of potential predisposing
factors for patients. (Reproduced
with permission from Quintessence
Publishing).2

subepithelial external root resorption, and idiopathic external resorption. They all refer to a relatively
uncommon form of dental resorption. If left undiagnosed, misdiagnosed, mistreated or untreated, it will
usually be quite devastating for a tooth. An Australian
dentist, Dr Geoffrey Heithersay, has contributed
much to the literature regarding all facets of this type
of dental resorption. His work has become the basis
of research and treatment. With few changes over
the past several years, the aetiology, predisposing factors, classification, clinical and radiological features,
histopathology and the treatment of this resorptive
process he described are still used in our practice
today.1–4, 6 For this reason, this article will adopt the
same nomenclature used in his numerous publications: invasive cervical resorption (ICR).

Unknown
0

Fig. 1

Number of teeth

ICR is not a common occurrence, is insidious and
often an aggressive form of external tooth resorption,
and can occur in any tooth in the permanent dentition.4 External resorption can be divided into three
broad groups: (a) trauma-induced tooth resorption;
(b) infection-induced tooth resorption; and (c) hyperplastic invasive tooth resorption.5 ICR is one form of
hyperplastic invasive tooth resorption.6 It results in
the loss of cementum and dentine by an odontoclastic type of action.7 The ICR lesion begins just apical
of the epithelial attachment of the gingiva at the
cervical area of the tooth, but can be found anywhere

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CE article _ invasive cervical resorption

Fig. 2b
Fig. 2a

on the root.8 Owing to its location, the beginning
lesion is difficult or almost impossible to recognise.
The exact mechanism of ICR is still not clearly understood. Microscopic analysis of the cervical region of
teeth has shown that there appear to be frequent gaps
in the cementum in this area, leaving the underlying
mineralised dentine exposed and vulnerable to osteoclastic root resorption.9 It is broadly accepted that
either damage to or deficiency of the protective layer
of cementum apical to the gingival epithelial attachment exposes the root surface to osteoclasts, which
then resorbs the dentine.7 In general, an area of radicular dentine around the cervical area of the tooth may
be devoid of the protective covering of cementum,
exposing the root surface to colonisation by osteoclast-like cells, allowing the resorptive process to
begin. Osteoclastic action in that area of the radicular
dentine eventually results in a hyperplastic resorptive
lesion containing fibro-osseous tissue. In order for
dental resorption to occur, three conditions are necessary: a blood supply, breakdown or absence of
the protective layer, and a stimulus. In the case of ICR,
the external protective layer is the cementum, and the
internal layer is the predentine of the pulp.
Several potential predisposing factors have been
identified: trauma, intracoronal bleaching, surgery,
orthodontics, periodontics, bruxism, delayed eruption, developmental defects, interproximal stripping
and restoration. Heithersay studied a group of 222
patients with a total of 257 teeth with various degrees
of invasive cervical resorption. From the subjects’
dental histories, it was determined whether there
was a sole predisposing factor, or a combination of
factors. The results are shown diagrammatically in
Figure 1.2 The results indicated that a history of orthodontic treatment was the most common sole
factor (found in 47 patients), while other factors,
mainly trauma and/or bleaching, were present in an
additional 11 subjects. Trauma was the second-most
common sole factor, with 31 teeth. Intracoronal
bleaching, combined with other factors, had the

Fig. 2c

third-most affected teeth.2 The pulp plays no role in
the aetiology of ICR and remains normal until the ICR
becomes very advanced.1, 7, 10
A recently published study has indicated there
might be a connection between human and feline ICR.
Four cases of multiple invasive cervical resorption
(mICR) were presented. There was direct contact
with cats in two cases, and indirect contact in the
other two cases. Neutralised testing was done for
feline herpes virus Type 1 (FeHV-1). Two of the cases
were neutralised, and two were partly inhibited. The
study indicates a possible transmission of FeHV-1 to
humans and the possibility of its role as an aetiological (co)factor in ICR.11

_Histology
An interesting observation is that even in extensive
lesions, the pulp is protected from the surrounding
resorptive process by a narrow band of dentine (Figs.
2a–c). In some cases of ICR, the clinical and histological views of the lesion substantiate that bone-like
tissue has replaced the fibro-vascular tissue located
within the resorptive cavity (Figs. 3a & b). In the larger
Class 3 and Class 4 lesions, communication channels

Fig. 3a

Figs. 2a & b_The pulp remains
intact, encircled by a narrow band of
dentine (red arrows). Histologically,
the pulp remains intact and is protected from the extensive resorptive
lesion by a narrow wall of dentine (a).
A low powered photograph shows
the walling off of the pulp by dentine,
protecting it from the surrounding
extensive resorptive process (b).
(Slide adaptation reproduced with
permission from Dr Geoffrey
Heithersay.)
Fig. 2c_High magnification of the
distal orifice of a mandibular second
molar being treated for ICR. The pulp
remains intact encircled by a narrow
band of dentine (bottom arrow). The
affected dentine can be observed
(middle arrow) and a possible distal
penetration area (top arrow).
(Slide adaptation reproduced with
permission from Dr Raphael Bellamy.)

Figs. 3a & b_Both the clinical
view (a) and histological view (b)
show how the dentine has been
extensively replaced by a bone-like
tissue. A mass of fibro-vascular
tissue infiltrated with inflammatory
cells is evident, located within a large
resorptive cavity that has a wide
connection with the periodontal
tissue (large arrow). A small section
of intact pulp can be seen on the
superior aspect of the section (small
arrow). Haematoxylin-eosin stain;
original magnification X 30.
(Reproduced with permission
from Quintessence Publishing
and Dr Henry Rankow.)1

Fig. 3b

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I CE article _ invasive cervical resorption
_Diagnosis
The earlier the diagnosis, the more predictable
the outcome of treatment will be. Owing to the nature of the lesion, treatment based on an incorrect
diagnosis will usually result in continued progression of the resorptive process and eventual loss of
the tooth.

Fig. 4a

Fig. 4b

Figs. 4a & b_Histological appearance
of an extensive ICR with radicular
extensions. Masses of ectopic calcific
tissue are evident both within the
fibro-vascular tissue occupying the
resorption cavity and on resorbed
dentine surfaces. In addition,
communication channels can be
seen connecting with the periodontal
ligament (large arrows). Other channels can be seen within the inferior
aspect of the radicular dentine (small
arrows). Haematoxylin-eosin stain;
original magnification X 30. Higher
magnification (b) shows communication channels from the periodontal
ligament to the resorbing tissue. An
island of hard tissue remains (‫)٭‬,
consisting of an external surface of
cementum and cementoid with some
residual dentine, but the bulk has
been replaced with a bone-like
material with a canalicular structure.
Although some red blood cells are
evident near the deeper channel, no
inflammatory cells can be seen.
Haematoxylin-eosin stain; original
magnification X 50.
(Reproduced with permission from
Quintessence Publishing.)1
Fig. 5_Clinical classification of invasive cervical resorption.
(Reproduced with permission from
Quintessence Publishing.)2

08 I roots
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Fig. 5

can be seen connecting with the periodontal ligament.
Other channels can also occur within the internal
aspect of the radicular dentine (Figs. 4a & b). The larger,
more advanced lesions can be described as consisting
of granulomatous bone-like fibro-osseous material
with a canalicular structure that has extensions into
the radicular dentine and periodontal tissue. Osteoclasts might be observed on the resorbing surface
within the lacunae.2 Over varying amounts of time,
the lesion expands apically and coronally, encircling
the pulpal tissue that is protected by a thin wall of
predentine and dentine.

_Clinical classification
Heithersay’s clinical classification was developed
as a guideline for treatment planning and comparative clinical research.2 The classification is shown
diagrammatically in Figure 5. The classification
allows the operator to determine the probable extent
of treatment more precisely. The more extensive the
lesion, the more complex the treatment options
become.
_Class 1: Small invasive resorptive lesion with shallow
penetration into dentine.
_Class 2: Well-defined invasive resorptive lesion close
to the coronal pulp chamber.
_Class 3: Deeper invasion extending into the coronal
third of radicular dentine.
_Class 4: A large invasive lesion extending beyond the
coronal third of the root.
Normally, a Class 1 lesion can be successfully
treated without much difficulty. Class 2 lesions
often require minor gingival flap surgery for retraction to achieve adequate access and removal of the
affected dentine, and to restore the defect. Class 3
lesions usually involve a surgical approach and/or or
orthodontic extrusion. Class 1 and 2 lesions can be
treated predictably, but the success rate in treating
Class 3 and 4 lesions drops dramatically. Thus, in
general, as the classification increases, the prognosis decreases.

Unfortunately, the smaller Class 1 lesion is often
not discovered owing to its location beneath the
gingival attachment, but will usually show a small
radiolucency on a radiograph. The dental examination may reveal a slight irregularity in the gingival
contour, which will bleed upon probing.4 It is my
experience that Class 1 lesions are seldom found
during routine dental examinations at this early
stage.
One of the problems with early diagnosis is that
the lesion is asymptomatic and can remain so even
in the more advanced stages. Pulp testing will be of
no value because the pulp remains unaffected until
late in the process. However, the larger Class 2 lesion
can present with more obvious clinical signs. For
example, a patient notices a pinkish area on an
anterior tooth. The discoloration is the result of osteoclastic activity replacing the radicular structure
of the tooth with reddish granulation tissue that
shows through the more translucent enamel.
Radiographically, the smaller Class 1 lesion can
be confused with a carious lesion, internal resorption or adumbration (cervical burn-out) of the radiograph. If the lesion is a Class 2, Class 3 or Class 4,
bitewing radiographs will often present an atypical
radiolucency and the examining dentist will be more
inclined to believe that it is not just a carious lesion.
If the lesion is on the proximal surface of the tooth,
the outline of the pulp can usually be observed. The
larger lesions can also be misdiagnosed as caries
or internal resorption. The usual indication that the
lesion is not carious is the irregularity of the radiolucency and/or the radiopaque outline of the protective predentine layer of the pulp (Figs. 6a & b). By
utilising varying angulation of the radiographs,
internal resorption can be ruled out. If the lesion is
due to internal resorption, it will remain centered
what the direction, or “off-angle” the radiograph is
taken. However, if the lesion is one of ICR, Clark’s
Rule, or SLOB Rule, can be used to determine the
location of the lesion (the most lingual object moves
with the direction of the X-ray head). (Figs. 7a & b).
With the advent of Cone Beam Computed Tomography (CBCT), the clinician is given the opportunity
to view teeth and anatomical entities in three dimensions. Compare with the typical periapical radi-

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CE article _ invasive cervical resorption

Fig. 6a

Fig. 6b

ographs (Fig. 8a). Even if numerous angles, a complete view of the extent of the lesion cannot be established with any definitive accuracy. The extracted
tooth #16 was a hopeless Class 4 lesion involving
most of the cervical half of the lingual surface and
extending into the area (Fig. 8b). Three planes of sections can be evaluated with CBCT: the frontal/coronal (X), sagittal (Y) and axial (Z; Fig. 8c). The X plane
moves anterior ⇔ posterior (B ⇔ L in the anterior
teeth and M ⇔ D in the posterior). The Y plane
moves left ⇔ right (M ⇔ D in the anterior and B ⇔
L in the posterior). The Z plane moves coronal ⇔
apical for all teeth in the dental arch. Depending on
the machine, up to 512 slices of the field of view can
be visualised. The slice thickness is variable, again
depending on the machine, from nearly 0.1 to several mm. However, generally speaking, the thinner
the slice, the higher the spatial resolution.12 When
evaluating resorptive defects, higher resolution and
3-D images allow the experienced clinician to make
a more definitive diagnosis and establish a confident and realistic plan for treatment, with a higher
predictability of success.
In summary, the characteristic diagnostic signs
that indicate that the lesion is a result of ICR are as
follows:

Fig. 7a

Fig. 7b

_Treatment
After the diagnosis of ICR has been confirmed, the
treatment should be scheduled as soon as possible. If,
for some reason this is not practical, the tooth should
be monitored closely. The lesion can be very aggressive, so best not to wait for too long (Figs. 9a–c).
The Heithersay classification is of great help for
advising the patient of the extent of treatment and
gaining a better idea of the possible prognosis. The
patient and doctor can decide on treatment together: (a) no treatment and extraction if the tooth
becomes symptomatic; (b) extraction and possible
replacement with an implant; or (c) to begin endodontic treatment in an attempt to eliminate the lesion and restore the tooth for as long as possible. In
Class 1 and Class 2 cases, the patient must be advised
that the treatment will probably be non-surgical but
that the surgical approach may be necessary. In the
more advanced Class 3 and Class 4 cases, the patient
must be advised that both the non-surgical and surgical approaches will be necessary. Dental implants
have become popular and, unfortunately, have led to
a greater percentage of patients choosing the first
two options.8 However, there are still enough pa-

Figs. 6a & b_The outline of the
pulp can usually be observed radiographically (a). The bitewing X-ray
(b) will show the ICR lesion and the
predentine layer (red arrows). The
predentine protective layer can exist
even in advanced Class 4 lesions
(red arrows).
Figs. 7a & b_A definitive way to
avoid a misdiagnosis of ICR is to
take the X-ray from varying angles,
including at a normal position (a).
However, when the X-ray is taken
from a different, more distal angle
(b), the radiograph clearly demonstrates that the lesion is not internal
resorption and is positioned to the
lingual surface. The protective
predentine layer surrounding the
pulp is clearly visible.

Figs. 8a & b_Pre-op PAX for
extraction of tooth #16 (a).
The extracted tooth (b).

_The tooth is asymptomatic.
_The pulp tests are within normal limits.
_The ICR defect moves with varying X-ray angulations.
_The protective pulpal wall is often intact and can be
seen on the radiographs.
_The portals of entry are near the osseous crest.
_The portals of entry are difficult to locate clinically.13
I suggest that during the initial dental examination
the patient be asked whether any of the three major
predisposing factors have occurred in their dental
history (bleaching, trauma or orthodontics). ICR can
occur in any permanent tooth and once found in a
patient, it is important to initiate regular follow-up
visits to ensure no further lesions occur.

Fig. 8a

Fig. 8b

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I CE article _ invasive cervical resorption

Fig. 9b

Fig. 8c

Fig. 9a

Fig. 8c_CBCT is essential to
demonstrate the extent of the lesion
and the amount of destruction that
has occurred.
Figs. 9a–c_In a matter of just a few
months, the lesion had advanced (a).
The diagnosis was made (b). The
patient was seen again in five months
and was scheduled for treatment (c).

Figs. 10a–c_Pre-operative X-ray (a).
Immediate post-op MTA fill (b).
Seven-month FUV (c).
Figs. 10d–f_Immediate post-op
radiograph following microsurgical
recontouring and enhancement of
previous MTA fill (d). The 44-month
FUV indicated an intact periodontal
ligament (e; red arrow). Pre-op
radiograph for extraction of tooth at
81 months (f). When comparing (f)
with (e), there appears the
probability of a continuation of the
resorptive process (arrow).

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Fig. 9c

tients who want to save their natural teeth, no matter what.
Heithersay developed what has become the
standard guide for the treatment of ICR. Depending on the extent of the lesion, it is accessed either
non-surgically or surgically. The granulation tissue
is removed with either curettes or a round bur of
varying sizes. During the removal of the bone-like
tissue, 90 % trichloroacetic acid (TCA) is applied
with a small cotton pellet numerous times, with increasing pressure, to achieve coagulation necrosis.
Using magnification, the fibro-osseous granulation tissue is removed until no communication
channels are observed and the defect is lined with
unaffected dentine, then restored with an appropriate restorative material. Endodontic treatment
is performed when indicated. The aim of treatment
is to eliminate all active resorbing tissue and
restoration of the defect so the tooth can be maintained for as long as possible.4 It has been my
experience that all Class 2 to 4 cases required
endodontic treatment.

absolutely no disagreement about the use of
TCA, but when the cases were treated, it was not
available. The cases were treated with what was on
hand. As a matter of convenience and necessity,
Monsel’s solution (MS), a 72 % solution of ferric
sulphate with sulphuric acid, was used. It had been
used for many years as a coagulant when performing apical microsurgery. The use of MS to
achieve coagulation necrosis when treating ICR
over the years appeared to work well. As a result,
the use of MS was continued.

_First patient

I wish to make something very clear. In the
following cases, 90 % TCA was not used. There was

In 1993, a 62-year-old male patient presented
for an evaluation of tooth #21 (Fig. 10a). His general
dentist had recommended that the tooth to be
extracted. At that time, a definitive protocol for the
diagnosis and treatment of ICR had not been established. But the patient wanted us to do something to
save the tooth. Sensing the sincerity of the patient,
we agreed to attempt the salvation of the tooth,
but informed him that we could not guarantee the
outcome. At that time, there were some practising
endodontists participating in clinical research for Dr
Torabinijad using mineral trioxide aggregate (MTA)

Fig. 10a

Fig. 10d

Fig. 10b

Fig. 10c

Fig. 10e

Fig. 10f

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I CE article _ invasive cervical resorption

Fig. 11a

Fig. 11b

Fig. 11f

Fig. 11c

Fig. 11d

Fig. 11g

Figs. 11a & b_The updated pre-op
radiograph indicated an advanced
Class 2 ICR (a). After gross removal
of granulation tissue, the affected
dentine could be seen (b).
Figs. 11c–f_A micro-brush was
used to apply Monsel’s Solution and
brushed onto the floor of the defect
(c). After application of the MS, the
area was irrigated with NaCl, rinsed
and dried for inspection of remaining
affected dentine (d). Note the perforation in the distal surface of the
tooth (large arrow), and remaining
affected dentine (small arrows; f).
A variety of Munce burs are available
for removal of the affected dentine.
Figs. 11f & g_Most of the lesion
has been removed, resulting in a
perforation of the distal wall of the
chamber into the gingival sulcus (f;
large arrow). A smaller Munce bur
will be necessary to remove slightly
more of the affected dentine (small
arrows). The epinephrine-soaked
pellet was placed for an adequate
time for haemostasis before bonding
a glass ionomer repair (g).
Figs. 11h & i_The immediate
post-op radiograph (h). The four-year
FUV radiograph indicates a healed
tooth (i).

12 I roots
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in pulp capping, perforations and root-end filling.14
I had used MTA on just a few patients previously and
had some confidence that it might serve as a last
hope in this case. The MTA was an easy material to
work with and required moisture to set completely. After the access was created, the obvious
haemorrhaging was difficult to control whenever
more granulation tissue was removed using
curettes and a #6 round bur. Ferric subsulphate (MS)
was repeatedly used for haemostasis, then irrigated
with a 50% sodium hypochlorite solution (NaCl)
and rinsed with sterile water, then gently air dried
using the Stropko Irrigator (DCI). Haemostasis was
achieved and vision was maintained while using
an Aus-Jena surgical operating microscope (SOM)
fitted with a co-observer tube for the assistant.
After shaping to a #80 Kerr file at the terminus, and
removing as much granulation tissue as possible,
the canal system and defect were again copiously
irrigated and dried as well as possible. Owing to the
size of the apical opening, extra-large absorbent
paper points (Kerr) were used to remove any remaining moisture and the entire case was obturated
using MTA. The post-operative radiograph indicated
that a significant amount of excess MTA was
extruded (Fig. 10b). The patient was dismissed and
reported no post-operative problems.
At the seven-month follow-up visit (FUV), the
tooth #21 was totally asymptomatic, but I was
concerned with the appearance of the very obvious
overfill on the radiograph and wanted to eliminate

Fig. 11h

Fig. 11e

Fig. 11i

the excess MTA with a surgical approach. If the patient was seen by another dental office in the future,
one could imagine someone saying, “Who in the heck
did this to your tooth?” (Fig. 10c). On the appointed
day, a full gingival flap was created and access to the
area was achieved. In order to minimise the vibration
that would be created when trimming the excess
MTA from the root surface, a high-speed surgical
handpiece with fibre optics (Impact Air 45 Star Dental), fitted with a surgical length, taper fissure #1171
bur (SS White), was used. After a satisfactory root profile had been established, a very small, inverted-cone,
surgical length #330 bur (SS White) was used to prepare any of the lesion’s periphery that was missed
during the original non-surgical treatment. Once the
necessary “troughing” had been completed, new MTA
was added to the originally placed MTA for a more
complete seal (Fig. 10d). Sutures were removed in a
few days, and healing was uneventful. Regular FUVs
were scheduled. A radiograph taken at the 44-month
FUV was diagnosed as healing complete with an
intact periodontal ligament (Fig. 10e).
About four years later, the patient returned with
a three-unit fixed bridge replacement of tooth #21.
The patient stated that tooth had become very loose
and it was removed. The preoperative extraction
radiograph was located (Fig. 10f). However, later comparison of the 44-month FUV to the pre-extraction
radiograph indicated a possible continuation of the
resorptive process—isn’t it amazing what you can see
when the light is just right?

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CE article _ invasive cervical resorption

_Second patient

_Third patient

A 64-year-old male patient presented for evaluation
of tooth #17 because of the unusual appearance of
the distal surface of the tooth. The previous clinical examinations and radiographs over the past ten months
had diagnosed ICR (Figs. 11a–c). An updated radiograph
was taken, all options were explained to the patient, and
endodontic treatment was initiated (Fig. 11a).

A 47-year-old male patient presented for evaluation of “a small area of tingling, or numbness to the
right of the nose”. The initial radiograph was classic for
ICR (Fig. 12a). All options were explained, and endodontic treatment was initiated.

The tooth was accessed and a gross removal of fibrous granulation tissue was achieved using curettage. The chamber was copiously irrigated with NaCl,
rinsed and dried gently. The ICR dentinal defect and
granulation tissue were evaluated to obtain a better
understanding of its position in relation to the distal
wall of the access and to the pulp tissue (Fig. 11b). A
micro-brush dipped in MS was applied to the involved area (Fig. 11c). The MS is used for coagulation
necrosis and to display the affected dentine that needs
removal. It is not necessary to use copious amounts
when applying the MS. Instead it is best to rely more
on a sequence of repeated brushing with MS, irrigation
with NaCl, rinsing and gentle drying. Study under the
SOM at varying magnifications for affected dentine
(Fig. 11d). Then, if necessary, remove more of the
affected dentine using varying sizes of Munce burs
(CJM Engineering; Fig. 11e). This process is repeated as
necessary to achieve adequate vision. The floor of the
access should be observed under the microscope at
varying magnifications to determine whether any
affected dentine remains. A celluloid strip was placed
in the distal sulcus to act as a barrier to the flowable
glass ionomer restoration (Fig. 11f). An epinephrinesoaked cotton pellet (EpiDry, Pascal) was also used to
maintain haemostasis and enable the attempt at a
non-surgical repair of the defect (Fig. 11g). The defect
was etched and restored with a bonded glass ionomer,
allowing the maintenance of sterility in the remaining
chamber until the endodontic treatment had been
completed. The pulp tissue was extirpated and canal
system partially shaped. Enough calcium hydroxide
(CaOH) was injected into the canals to cover the floor
of the chamber, capped with a cotton pellet, and sealed
with a bonded composite as a temporary restoration.
Two weeks later, the patient was scheduled to complete the endodontic treatment. During the process, a
#6 file separated in the apical third of the distobuccal
canal and had to be retrieved. At the final visit, the canal
system was obturated using a Calamus (DENTSPLY
Tulsa) for the injection of pre-warmed gutta-percha to
the terminus. A bonded composite core was placed to
seal the rest of the canal system and facilitate future
restoration with a crown (Fig. 11h). The restorative dentist extended the distal margin of the full crown well apical to the distal defect for a good seal. The four-year FUV
radiograph demonstrated complete healing (Fig. 11i).

The tooth was accessed, and as much fibrous granulation tissue was removed as possible. Monsel’s solution was applied using a micro-brush to achieve coagulation necrosis. Then the chamber was irrigated with
NaCl, rinsed with sterile saline, and gently dried using
the Stropko Irrigator. The floor of the access was observed under the microscope at varying magnifications
to determine whether any affected dentine was present. Any remaining affected dentine was efficiently removed with various Munce burs. Then CaOH was sealed
in with a bonded composite as a temporary restoration.

Fig. 12a

Fig. 12b

Two weeks later, the patient was seen in order to
complete the non-surgical part of the treatment. The
final shaping and cleaning was done, and the canal
was filled to the terminus by injection of pre-warmed
gutta-percha using a Calamus. A bonded FibreKor
post (Pentron) with a bonded composite core (Core
Paste, DenMat), was placed to seal the rest of the canal
system and DenMat Marathon to repair the access
opening. Then a simple flap was reflected to expose
the lingual defect so it could be prepared and restored
with bonded Geristore (DenMat; Fig. 12b). Healing
was uneventful, and the numbing sensation beside
the patient’s nose was resolved. The radiograph at the
four-year FUV showed uneventful healing (Fig. 12c).

Fig. 12c

Figs. 12a–c_The pre-op radiograph
clearly demonstrates the appearance
of the protective layer and the typical
mottled radiolucent appearance
of the resorptive lesion (a). The
radiograph immediately after nonsurgical obturation and surgical
repair of the lesion (b). Normal
healing is apparent in the four-year
FUV radiograph (c).

_Fourth patient
This 64-year-old male patient was referred by his
general dentist because of the unusual radiographic
appearance of tooth #43 (Fig. 13a). Even though there
were no symptoms present, the referring doctor was

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I CE article _ invasive cervical resorption
Figs. 13a & b_At the initial visit, the
radiograph for tooth #43 in a 64-yearold male patient was taken at a normal
angle (a). Taking a radiograph from a
more distal angle demonstrated that
the lesion was located to the lingual of
the tooth. Both radiographs clearly
show the protective dentinal wall
surrounding the pulp (b).

concerned about the integrity of the tooth. Routine
off-angled periapical radiographs were taken. The
distal off-angled radiograph clearly indicated that the
lesion was on the lingual surface of the tooth (Fig. 13b).
Both radiographs clearly showed the thin predentine/dentinal wall protecting the pulp. His dental history revealed that he had had complete orthodontics
during his early teens. In addition, the patient stated
that tooth #43 had become misaligned about 20 years

Microscopic description: Histological examination reveals multiple pieces of soft and hard tissue
composed chiefly of inflamed granulation and fibrous connective tissues with bone and tooth structure. The granulation and fibrous tissues consist of
interlacing bundles of dense to more delicate collagen fibres supporting varying numbers of fibroblasts,
fibrocytes and small blood vessels. A mild infiltrate
of chronic inflammatory cells, chiefly lymphocytes
and plasma cells, is present within this tissue. Also
prominent within our specimen are scattered trabeculae of bone containing osteocytes within lacunae,
as well as fragments of dentinal tooth structure and
calcified debris.
Diagnosis: Right posterior mandible, lingual aspect of tooth #43. Histological findings consistent
with idiopathic external resorption.

Fig. 13a

Fig. 13b

Fig. 13c

Fig. 13d

Fig. 13e

Fig. 13f

Figs. 13c & d_The initial access
demonstrated the unusual texture
of the fibrous bone-like granulation
tissue in the coronal area (c; arrow).
After removal of most of the granulation tissue, white MTA was placed
into the chamber and a temporary
placed (d).
Figs. 13e & f_At the second visit,
in an attempt to maintain the vitality
of the pulp, MTA was placed into
the canal (e; arrow). CaOH was
placed as an inter-appointment
medication and to allow the MTA
to achieve a complete set (f).
Figs. 13g & h_After a few days,
the chamber was irrigated and
a bonded core was placed and was
finished with a bonded composite
(DenMat; g). The two-month FUV
radiograph demonstrated that the
attempt to maintain the vitality of the
tooth had not been successful (h).

14 I roots
4_ 2012

ago. In order to correct the misalignment of the tooth,
the doctor reduced the tooth on each side and repositioned it with a removable appliance. Clinical examination was essentially within normal limits, except that
a 4-6-4mm periodontal probing of the lingual tissue
resulted in moderate bleeding. All teeth in the posterior
quadrants had been restored with full porcelain coverage, and the occlusion was a normal Class 1 molar
relationship. All pulp tests were within normal limits.
The diagnosis was clearly a Class 3 ICR. All things were
explained to the patient, and we agreed to be as conservative as possible during treatment. At the time, I had
no idea what a learning experience this case would be.
At the first visit, the initial access confirmed the
diagnosis. The granulation tissue consisted of granules of bone-like haemorrhagic tissue (Fig. 13c). The
pulpal wall was very thin, and pieces would come
out with the granulation tissue. During the curettage,
the fibrous tissue resembled a “crumbling sponge
made of bone that was soaked with blood”. Pieces of
tissue were sent to an oral pathology laboratory for
the following definitive diagnosis:

Gradually, as more of the tissue was removed, the
bleeding noticeably decreased, but haemostasis was
not achieved. As an interim medication, a thick mixture of white MTA was firmly placed into the chamber,
covered with a sterile cotton pellet and temporarily
restored with a bonded composite (Fig. 13d). During
the initial examination, pulp testing indicated a normal pulp, and I was wondering whether the vitality of
the tooth could possibly be maintained at that point.
All options, including the possible need for conventional root-canal treatment, were explained. Both the
doctor and patient agreed to attempt to maintain the
vitality of the tooth. The patient was rescheduled for
a second visit in about two weeks.
During the second visit, the chamber was reopened, the MTA was eliminated and more granulation tissue was removed with small curettes. Under
varying high magnifications of the microscope
(Global Surgical Corporation), as much of the remaining affected dentine was removed with Munce
burs, and the remaining pulp tissue was identified.
After irrigation with NaCl, an additional few millimetres of the pulp was removed and a pellet of grey
MTA was placed into the canal using a medium
Dovgan MTA Carrier (Quality Aspirators; Fig. 13e).
CaOH was then placed, covered with a cotton pellet,
and sealed in with a bonded composite temporary
(Fig. 13f). To allow for a complete set of the MTA, the
patient was scheduled two days later for a third
appointment.
On this third visit, the CaOH was removed, and the
floor of the defect was lightly brushed with Munce
burs of various sizes and studied under varying
magnifications until no affected dentine was observed. The chamber was irrigated with NaCl, rinsed,
gently dried and etched with 35% phosphoric acid
gel (Ultra-etch, Ultradent). A bonded core was placed

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CE article _ invasive cervical resorption

Figs. 13i & j_The MTA was removed,
the canal shaped, and CaOH sealed
with a bonded temporary (i). The
canal was obturated with guttapercha and a bonded fibre post with
a composite core was placed (j).

Fig. 13g

Fig. 13h

and access restored with a bonded composite (Fig.
13g). An FUV was scheduled for two months later.
At the two-month FUV, the periapical radiograph
revealed that the response to treatment was not as
expected. The ICR lesion had significantly progressed in that short time (Fig. 13h). All options were
discussed with the patient, but there was no doubt
that conventional endodontic treatment, followed
by surgical repair of the lesion would be necessary.
During this visit, adequate access was created
to remove the previously placed MTA. Using Gates
Glidden burs and a #4 round bur, more affected dentine was removed in the coronal aspect of the canal.
The canal system was then shaped and cleaned to the
terminus, and CaOH was sealed in with a bonded
composite temporary (Fig. 13i). After about ten days,
the canal system was obturated by the injection of
pre-warmed gutta-percha to the terminus with a
Calamus. Then, most of the core was removed and a
post space created. A fibre post with a composite
core was bonded in, and the access opening filled
with Geristore to prepare the tooth for the surgical
repair of the ICR lesion (Fig. 13j).
A sulcular flap was reflected enough to adequately
access the ICR lesion. The lesion was at the lingual
crestal bone and had been slightly stained from the
previous use of Monsel’s Solution (Fig. 14a). After
gross removal of the remaining granulation tissue
and affected dentine, more solution was applied with
a micro-brush to achieve coagulation necrosis and
the stained affected dentine was removed using
smaller Munce burs (Fig. 14b). The process was repeated until all affected dentine had been removed.
After the preparation had been completed, a bonded
Geristore was placed (Fig. 14c). A radiograph from a
normal view indicated that the restoration was
appropriate (Fig. 14d). A radiograph was taken from a
distal off-angle view to ensure that post-operative
integrity had been achieved (Fig. 14e).
The patient was followed at regular intervals.
The most recent FUV occurred after over eight years

Fig. 13i

Fig. 13j

post-operatively. The patient remained asymptomatic from the beginning to the end of the entire
treatment process. The recent buccal view does
show a slight grey shadow in the cervical half of the
tooth as a result of the earlier use of the MTA when
trying to maintain the vitality of the pulp (Fig. 14f).
Apart from normal staining, the lingual view was
within normal limits and the periodontal probing
was still 5mm (Fig. 14g). The post-operative radiographs indicate complete healing with good integrity of the fill (Figs. 14h & i). Note that the excess
filling material from the original obturation (Fig. 13i)
was resolved.

_Discussion
Unfortunately, ICR is normally not detected in its
early stages and/or is often misdiagnosed. By the time
it is discovered, the resorptive process is advanced
enough to be at least a Class 2 or worse. Fortunately,
ICR is not a very common occurrence in an endodontic practice, though it can be quite demanding of our
time. Some Class 2 ICR cases and all Class 3 and Class
4 cases, with rare exception, will involve conventional
endodontic treatment.

Fig. 14a

Fig. 14b

Fig. 14f

Fig. 14g

Figs. 14a & b_After a surgical flap
had been raised, the ICR lesion was
observed at the lingual crest of bone.
“X” is the glass ionomer placed at
the pre-surgical appointment (a).
After each application of Monsel’s
solution, the granulation tissue was
removed with various sizes of Munce
burs. The apical portion of the
preparation is shown (b).
Figs. 14c–e_A bonded glass
ionomer was placed and cured (c).
Immediate post-op radiograph (d).
The radiograph from a distal offangle shows integrity of the post
and core (e).
Figs. 14f & g_The eight-year FUV
indicates healthy tissue on both the
buccal (f) and the lingual views (g).
Note the slight grey shadow left as
the result of using grey MTA at the
beginning of the non-surgical
treatment.
Figs. 14h & i_Radiographs taken
at a normal angle (h) and at a mesial
off-angle (i) also indicate complete
healing.

Fig. 14c

Fig. 14d

Fig. 14h

Fig. 14e

Fig. 14i

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I CE article _ invasive cervical resorption
The diagnosis of ICR is made more precise with
currently available radiographic technology. Digital
radiographs and CBCT have set a new standard of
clinical management, allowing more predictable results with less stress. The 3-D view presented by CBCT
removes many of the unknowns from the diagnosis.
In today’s world, the use of a surgical operating
microscope (SOM) is essential to enable the operator
to overcome the difficulty of treating ICR cases. The
variable magnification and superior lighting of the
SOM give the operator the enhanced vision necessary
to treat ICR cases with less stress and a higher probability of success. Having a dental assistant involved,
using a co-observer tube during any dental procedure, is an incredible help because now he or she is
able to see what you see at the time you see it and
better anticipate what is needed next.
In all cases presented, Monsels solution (MS) was
used successfully for coagulation necrosis. Based
on an early report, I used it routinely during microsurgery for crypt management.15 As a result, when the
first case of ICR presented for treatment, 90% TCA
acid was not a familiar alternative protocol. Having
never used TCA, I can offer no comparison or comment. The original protocol for the clinical management of ICR using 90% TCA, suggested by Heithersay
in 1999, is still the most popular and well documented.
There are various techniques for restoring a tooth
with ICR, as previously described in the literature, that
are different from what is presented in this publication. However, the real purpose in the treatment of
ICR was, and still is, to eliminate as much of the
affected dentine as possible. If this is not achieved, the
process will progress and be a disaster for the tooth.

_about the author

roots

John J. Stropko received his DDS from Indiana University in
1964. For 24 years, he practised restorative dentistry. In
1989, he received a certificate for endodontics from Boston
University and has recently retired from the private practice of
endodontics in Scottsdale, Arizona. Stropko is an internationally recognised authority on micro-endodontics and has performed numerous live micro-endodontic and microsurgical
demonstrations. He has been a visiting clinical instructor at the
Pacific Endodontic Research Foundation, an adjunct assistant
professor at Boston University, an assistant professor of graduate clinical endodontics
at Loma Linda University, and a member of the endodontic faculty at the Scottsdale
Center for Dentistry in Scottsdale, as an instructor of microsurgery; and is a co-founder
of Clinical Endodontic Seminars. His research on in vivo root-canal morphology has
been published in the Journal of Endodontics. He is the inventor of the Stropko Irrigator, has published in several journals and books, and is an internationally known
speaker. Stropko and his wife currently reside in Prescott, Arizona.
He may be contacted at docstropko@gmail.com

16 I roots
4_ 2012

While MTA was extensively used in the first case
presented (Figs. 13a–g), I do not intend to suggest
the use of it as a material for the repair of ICR defects.
I did that case almost 20 years ago. Today the materials of choice would be bonded glass ionomers or
composites for their strength and adhesiveness.
MTA is currently used as a pulp capping material,
for perforation repairs or as a restorative material for
the repair of a radicular defect that is apical to the
osseous crest.
It is important to remember that unless the
challenge to treat a seemingly hopeless or extremely
difficult case is accepted, the opportunity to learn
what can be accomplished is lost. Experience has
shown that in such cases there have been more
pleasant and favourable surprises than unpleasant
results. As William F. O’Brien said, “It is better to try
and fail, than to not try at all.” Hindsight is always
20-20, and it is one of the best teaching tools we
always have at our disposal. The important thing is
to learn from our mistakes and those of others.
If a tooth can be saved for only a few years, the
rapid advancement of technology will permit a
significantly better treatment in the future. So, if an
opportunity is presented to save the tooth, then why
not? If the question remains, the words of Dr Herbert
Schilder are pertinent, “Make yourself the patient,
and you have the answer!” The important consideration is what is in the best interest of the patient.
Remember, an implant can always be done, and
should be the last resort.
In conclusion, the quote from Dr Henry Rankow
gives the best explanation of the predicament presented for the clinical management of this lesion,
“ICR is an ‘outside-in’ problem that is very difficult to
treat ‘inside-out’!”

_Acknowledgements
I wish to acknowledge Dr Geoffrey Heithersay
for establishing the protocol in the diagnosis and
clinical management of ICR. In addition, I would like
to thank Dr John Hughes for enabling me to become
a member of this incredible specialty and Dr Herb
Schilder (deceased), who instilled the passion in
many of his students for predictability in endodontic procedures. Thanks also to Dr Kent Banta and
Dr Tom McClammy for being there when needed for
technical issues. Most important of all, I want to
acknowledge Barbara, my wife, my chairside assistant and constant support for the past 30 years, in
our journey toward excellence in endodontics._
Editorial note: A complete list of references is available
from the publisher.

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I case report _ iatrogenic errors

Iatrogenic errors before
and after non-surgical
root-canal treatment
Author_ Dr Rafaël Michiels, Belgium

Fig. 1_Diagnostic radiograph,
showing the separated instrument
in the mesiobuccal canal.
Fig. 2_Size 15 Flexile file passing
through the perforation.

18 I roots
4_ 2012

Fig. 1

Fig. 2

_Several reports in the literature describe iatrogenic errors during root-canal treatment. The most
common errors include perforations, ledging, transportation, zipping, overextension, file separation and
underfilling. Little emphasis is placed on the preparation of a tooth before starting root-canal treatment,
or on the finishing of the tooth after obturation of
the root-canal system. On various online forums and
in several clinical articles, beautifully executed rootcanal treatments are shown with coronal restorations
that are less than ideal. This is a serious problem, since
it has been demonstrated that a successful outcome
depends not only on adequate root-canal treatment,
but also on adequate coronal restoration. In this
article, I will elaborate on these aspects and present a
case as an example.

_Before starting root-canal treatment
As endodontists, we are specialised in the treatment of root-canal systems. However sometimes we
focus on this only, forgetting that there is more to a
tooth than a root. When a patient comes into our office, often he will have (a) symptomatic apical periodontitis. Whether the tooth has been treated before
is somewhat irrelevant in the scope of this article.
The first thing that we, as practitioners, should try to
determine is the cause of the problem. The most cited
causes are previous inadequate root-canal treatment, primary decay, recurring decay, worn restorations and poor restorations overall. If the tooth has
not undergone root-canal treatment previously,
then the cause of the problem is most likely one of the

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case report _ iatrogenic errors

coronal factors. It is important to address this. After
all, what is the point of performing a beautiful rootcanal treatment if the primary cause of the problem is
not treated?
The best way to do this is by removing the old
restoration completely, followed by full caries removal. This may sound logical, but it is not. There are
certain disadvantages with this approach, and it is
these disadvantages that guide many practitioners
in their decision-making. Removing an existing
restoration might result in the sacrifice of healthy
tissue and it might make it more difficult to obtain
proper isolation with a rubber dam. Another factor is
time; removing an old restoration is time-consuming
and even more so if a build-up is required before
endodontic treatment. These are some reasons that
many practitioners choose to leave the old restoration in place. This can compromise the treatment
outcome and is a risk that can be avoided.

Fig. 3

Fortunately, there are advantages too. By removing the old restoration and subsequently all the
caries, the practitioner eliminates one of the major
causes of failure and can assess immediately whether
the tooth is restorable and thus avoid unnecessary
treatment. Another advantage is that it is necessary
to fabricate a completely new restoration afterwards,
which avoids patching up of old restorations. Overall,
the advantages are greater than the disadvantages
and the only thing it requires from the practitioner is
a change in behaviour and some perseverance.

_After root-canal treatment
Fig. 4

Once root-canal treatment has been completed,
often we need to send the patient back to the referring dentist. In this case, an adequate temporary
restoration must be placed. Typically, a temporary filling material like Cavit (3M ESPE) or a glass ionomer
cement is used. A cotton pellet or some other form of
space maintainer is generally placed underneath this
temporary filling. This is done because the referring
dentist then has easier access to the pulp chamber
so that he can gain better retention when placing
the permanent restoration. There are several disadvantages to this approach. Leaving space between the
temporary restoration and the canal orifices puts the
patient at risk of contamination. As practitioners we
cannot guarantee that the patient will show up for the
permanent restoration, sometimes the appointment
is cancelled for a variety of reasons. Another risk is
fracture of the restoration and/or tooth. If that happens the gutta-percha can be exposed to saliva, which
too might lead to contamination. Ideally, however, the
tooth should be restored immediately after the rootcanal treatment has been carried out. This means that
the endodontist places the permanent restoration.

Advantages with this approach are:
_It saves the patient a visit to his regular dentist.
_The tooth is already isolated, creating the ideal environment for a restoration.
_It saves the referring dentist time, which he can
spend on other treatments.
_It offers the endodontist some variety in the treatments he performs, enabling him to broaden his skill
set.

Fig. 5

Fig. 3_Perforation repair with grey
MTA-Angelus.
Fig. 4_Post-op radiograph.
Fig. 5_Follow-up radiograph after
nine months, showing coronal
restoration that was less than ideal.

Again, this only requires a change in behaviour of
the practitioner and some perseverance. It will also
require that the referring dentist allow the endodontist to place the restoration. The endodontist will
have to upgrade his skills, so that he can also create
beautiful coronal restorations.
Following, is a case that illustrates the advantages and disadvantages of the above-mentioned
approaches.

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I case report _ iatrogenic errors

Fig. 6

Fig. 7

Fig. 6_Diagnostic radiograph of
another referred tooth (tooth #16).
Fig. 7_Working length,
together with complete removal
of the old restoration.
Fig. 8_Post-op radiograph, with
temporary glass ionomer restoration.

_Case report
When I had just graduated as an endodontist,
a 36-year-old male patient was referred because he
was experiencing some mild pain in his left mandibular second molar. I was acting as a third-line practitioner in this case. Another endodontist did not wish
to begin treatment and finally referred the patient to
me.
The tooth was diagnosed as having symptomatic
apical periodontitis and was previously treated inadequately, including a separated instrument in one of
the mesial canals (Fig. 1).
In the first visit, I removed the gutta-percha from
the mesiolingual canal, and cleaned and shaped it
completely. The separated instrument was located in
the mesiobuccal canal, but I could not remove it
completely. I left the distal canal untouched. Calcium
hydroxide was used as an inter-appointment dressing,
and the tooth was restored with a cotton pellet and
glass ionomer cement. An initial error was made by not
removing the old restoration and caries completely.
One month later the patient returned in agony.
When I re-opened the tooth, a great deal of pus and
blood came out of the tooth. I then tried to bypass the
remainder of the fragment in the mesiobuccal canal,
but perforated the root with a 15.04 ProFile (DENTSPLY Maillefer; Fig. 2). I also retreated the distal canal
in this session and fractured a small piece of a 25.06
ProFile in the apical part, but could bypass it. I then
filled the canals again with calcium hydroxide and
sealed the tooth with a glass ionomer filling.
One month later, I saw the patient again for the
completion of the treatment. He no longer had any
symptoms. I restored the perforation with grey MTAAngelus (Fig. 3). I obturated the canals with guttapercha and Topseal (DENTSPLY Maillefer) using warm
vertical condensation. I sealed the cavity with Fuji IX
A1 (GC) immediately on top of the gutta-percha
(Fig. 4). I then referred the patient back to the dentist
for a permanent restoration, with the explicit advice
to have the distal restoration replaced too.

20 I roots
4_ 2012

Fig. 8

Nine months later the patient returned to my
office for another tooth. I decided to take a followup radiograph of the left mandibular second molar
to see if healing was favourable. The patient had not
experienced any complaints since I completed the
treatment and the radiograph showed a favourable
apical outcome. However, the permanent restoration was less than ideal (Fig. 5). I had to refer the
patient back to the dentist for a new restoration.

_Conclusion
Looking back upon this case, I can conclude that
I should have removed the old restoration and the
caries at the start of the treatment. Positively, it was
good that the glass ionomer filling was placed immediately above the canal orifices, preventing contamination via a leaky restoration. Ideally, I should
have finished the restoration myself.
It required a change in my behaviour and some
perseverance to begin to perform cases in accordance
with the afore-mentioned approaches, as can be seen
in Figures 6, 7 and 8._

_about the author

roots

Dr Rafaël Michiels
graduated from the Department of Dentistry at Ghent
University, Belgium, in 2006.
In 2009, he completed the
three-year postgraduate
programme in endodontics
at Ghent University. He
works in two private practices specialised in endodontics in Belgium. He can
be contacted at rafael.michiels@ontzenuwen.be
and via his website www.ontzenuwen.be

[21] => RO0110_01_Titel

[22] => RO0110_01_Titel

I research _ irrigation

Fluid dynamics of syringebased irrigation to optimise
anti-biofilm efficacy in
root-canal disinfection
Authors_ Dr Christos Boutsioukis, Netherlands, & Dr Anil Kishen, Canada

_Bacterial biofilm as a therapeutic target root canals of both untreated and treated teeth with
A mature bacterial biofilm is composed of multiple layers of bacteria embedded in a self-made matrix formed of extracellular polymeric substance. This
substance has the potential to modify the response
of the resident bacteria to antimicrobials by acting as
a shield against the chemical effects of antimicrobials. There is also a localised high density of bacterial cells in a biofilm structure. This spatial arrangement will expose the cells in the deeper layers of the
biofilm to less nutrients and redox potential than the
cells on the biofilm surface. Since the degree of nutrient and gas gradients increases with the thickness
and maturity of a biofilm, the influence of growth
rate and oxygen on the antimicrobial resistance is
particularly marked in aged biofilm. The resistance
associated with biofilm bacteria is further associated
with the slow growth rate (starvation) and/or due
to the adoption of resistant phenotypes in bacteria
residing in a biofilm. It is recognised that no single
mechanism may account for the general resistance
to antimicrobials in a biofilm. It is apparent that
different mechanisms may act in concert within the
biofilm, and amplify the effect of small variations
in the susceptible phenotypes (Dunne et al. 1993;
Costerton et al. 1994). Thus from a clinical perspective, bacteria are observed to demonstrate considerably high resistance to antimicrobials when they are
in a biofilm (Kishen 2012).
The current concepts in endodontic microbiology
emphasise endodontic disease as a biofilm-mediated
infection. Ricucci and Siqueira (2010) found a very
high prevalence of bacterial biofilms in the apical

22 I roots
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apical periodontitis. The pattern of arrangement of
bacterial communities in the root canal is noted to be
consistent with the acceptable criteria for including
apical periodontitis in the set of biofilm-mediated
diseases. They also suggest that the biofilm morphology/structure varied from case to case, and no
unique pattern for endodontic infections was determined. Elimination or significant reduction of endodontic bacterial biofilms is essential for successful
outcomes of endodontic treatment (Fig. 1). However,
clinical studies have demonstrated that even after
meticulous chemomechanical disinfection and obturation of the root canals bacteria may persist in
the un-instrumented portions and anatomical complexities of the root canal (Nair et al. 2005). It is vital
to comprehend that the limitations in endodontic
disinfection are not just due to the biofilm mode of
bacterial growth in the root canals. The complexities
of the root-canal system, in addition to the structure and composition of the root dentine, play a decisive role in limiting the efficacy of endodontic disinfection. Nair et al. (2005) demonstrated that following one-visit conventional endodontic treatment
the teeth revealed microbial biofilm in the inaccessible recesses and diverticula of instrumented main
canals, the intercanal isthmus and accessory canals.
The main limiting factors in conventional irrigation
are the complexity of the root-canal anatomy, the ultrastructure of the dentine and the characteristics of
the bacterial biofilms (Kishen 2010). Attempts to surmount these limitations have recently led to renewed
interest in understanding the fluid dynamics associated with different root-canal irrigation techniques
through numerical and experimental investigations.

[23] => RO0110_01_Titel

research _ irrigation

_General considerations of fluid
dynamics in irrigation
Endodontic irrigants are primarily liquid antimicrobials used to combat microbial biofilms within
the root-canal system. The process of delivery of
irrigants within the root canal is called irrigation,
and irrigation dynamics deals with how irrigants
flow, penetrate and exchange within the root-canal
space, and the forces produced by them. Hence, in
endodontic disinfection, the process of delivery is
as important as the antibacterial characteristics of
the irrigants. The overall objectives of root-canal
irrigation are (a) to inactivate bacterial biofilms, inactivate endotoxins, and dissolve tissue remnants/
smear layer (chemical effects) from the infected
root canals; and (b) to allow the flow of irrigant
throughout the root-canal system in order to detach the biofilm structures and loosen/flush out the
debris from the root canals (mechanical effects).
The chemical effectiveness will depend upon the
concentration of the antimicrobial irrigant, the area
of contact and the duration of interaction between
irrigant and infected material. The mechanical effectiveness will depend upon the ability of irrigation
to generate optimum streaming forces within the
entire root-canal system. Mechanical effects can be
produced even by inert irrigants (e.g. water, saline),
but chemical effects are only exerted by chemically
active solutions (e.g. sodium hypochlorite). The final
efficiency of endodontic disinfection will depend
upon its chemical and mechanical effectiveness
(Gulabivala et al. 2005; Haapasalo et al. 2005). Currently, there is no consensus on the relative importance of these effects for the overall success of rootcanal treatment; therefore, efforts to maximise both
effects seem justified. Even the most powerful irrigant will be of no use if it cannot penetrate the apical portion of the root canal, interact with the rootcanal wall and exchange frequently within the rootcanal system (Druttman & Stock 1989; Mott 1999;
Tilton 1999; White 1999; Seal et al. 2002). However,
over-enthusiastic efforts to deliver the irrigant
may result in its inadvertent extrusion towards the
periapical tissue (Hülsmann et al. 2009). Depending
on the irrigant, severe tissue damage, pronounced
symptomatology and possibly delayed healing
may develop, as documented in a number of case reports (e.g. Hülsmann & Hahn 2000; Gernhardt et al.
2004; Bowden et al. 2006; Pelka & Petschelt 2008;
Behrents et al. 2012). Therefore, irrigant penetration should be kept within the confines of the rootcanal system and a critical balance should always
be maintained between efficient cleaning and prevention of irrigant extrusion (Haapasalo et al. 2010),
especially when chemically active irrigants are
used.

Fig. 1

In general, root-canal irrigation can be regarded
as the flow of a liquid (irrigant) within an irregularly
shaped domain (root-canal system). Consequently,
a fluid dynamics approach would be appropriate for
elucidating the procedures of root-canal cleaning
and disinfection. The above-mentioned objectives
of root-canal irrigation can be restated briefly in
terms of fluid dynamics as:

Fig. 1_Multispecies bacterial biofilm
grown on root-canal dentine in vitro.

_flow of the irrigant to the full extent of the rootcanal system and subsequently to the canal orifice
in order to come in close contact with microbes,
debris and tissue remnants, and carry them
away;
_frequent refreshment and mixing of the irrigant
in order to retain a high concentration of its active component(s) and compensate for its rapid
consumption (for chemically active irrigants);
_application of force to the canal wall (wall shear
stress) in order to detach/disrupt microbes/
biofilm, debris and tissue remnants;
_restriction of the flow within the confines of the
root canal and prevention of irrigant extrusion
towards the periapical tissue (Boutsioukis 2010).

roots
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[24] => RO0110_01_Titel

I research _ irrigation

Fig. 2

Fig. 2_Commercially available
30 G needles: open-ended needles
(A—flat; B—bevelled; C—notched),
closed-ended needles (D—sidevented; E—double side-vented).
Variable views and magnifications
were used to highlight differences in
tip design. (Reprinted with permission from Boutsioukis et al. 2010b.)

_Syringe irrigation
Irrigant delivery techniques are frequently categorised as positive-pressure or negative-pressure,
according to the mode of delivery employed (Brunson
et al. 2010). In positive-pressure techniques, the
pressure difference that is necessary for irrigant flow
is created between a pressurised container (e.g. a syringe) and the root canal, where the pressure remains
much lower (nearly atmospheric). Irrigant is delivered
deep inside the root canal, usually by a needle, and
then flows towards the canal orifice, where it is
evacuated by a suction system. In negative-pressure
techniques, the irrigant is delivered passively near the
canal orifice at nearly atmospheric pressure and a
suction tip placed deep inside the root canal creates a

Fig. 3_Time-averaged contours
(right) and vectors (left) of velocity in
the apical part of a size 45 root canal
with a 0.06 taper during syringe
irrigation using various needle types:
open-ended (A–C), closed-ended
(D & E). All needles are positioned at
3 mm short of WL. (Reprinted with
permission from Boutsioukis et al.
2010b.)

Fig. 3

24 I roots
4_ 2012

pressure difference. The irrigant then flows from the
orifice towards the apex, where it is evacuated.
Perhaps the most traditional method of positivepressure irrigant delivery is by a syringe and a needle.
Despite the development of various irrigation systems, conventional syringe irrigation remains widely
accepted (Ingle et al. 2002; Peters 2004; Dutner et al.
2012). However, over the years it has been argued that
the performance of root-canal irrigation is limited
mostly because syringes and needles fail to deliver the
irrigant to all the parts of the complex root-canal system (Ram 1977; Rosenfeld et al. 1978; Druttman &
Stock 1989; Haapasalo et al. 2005). A detailed evaluation of the irrigant flow developed during syringe irrigation could provide some insight into this problem.

[25] => RO0110_01_Titel

research _ irrigation

_Irrigant flow during syringe irrigation
Most studies on root-canal irrigation have focused on the direct outcomes of irrigation, that is
debridement, tissue dissolution, antimicrobial action
or removal of the smear layer, employing a trial-anderror approach and speculating on the aetiology. Few
studies have actually attempted to evaluate directly
the flow developed within the root canal (e.g. Teplitsky et al. 1987; Druttman & Stock 1989; Kahn et al.
1995; Bronnec et al. 2010a; Boutsioukis et al. 2009;
Shen et al. 2010), which is probably the dominant
phenomenon during root-canal irrigation and the
primary cause of both the chemical and mechanical
effects.
The flow of irrigants is affected by their physical
properties, mainly density and viscosity (White 1999).
“Density” describes the amount of mass present in a
certain volume of the irrigant, and “viscosity” describes the resistance of the irrigant to motion (Mott
1999; Tilton 1999; White 1999). For commonly used
endodontic irrigants, these properties are very similar
to those of distilled water (Guerisoli et al. 1998; Van
der Sluis et al. 2010), which can be explained by the
fact that irrigants are mainly sparse aqueous solutions. The surface tension of endodontic irrigants and
its decrease by wetting agents (surfactants) has also
been studied extensively, under the assumption that
it may have a significant effect on irrigant penetration in dentinal tubules and accessory root canals
(Abou Rass & Patonai 1982; Taşman et al. 2000) and
on dissolution of pulp tissue (Stojicic et al. 2010).
However, while density and viscosity affect the flow
in all cases, the effect of surface tension is important
only at the interface between two immiscible fluids
(e.g. between irrigant and an air bubble, but not between irrigant and dentinal fluid; White 1999; Kundu
& Cohen 2004). Should an air bubble occupy the
apical part of the root canal (Tay et al. 2010), surface
tension effects could be important, but it is unlikely
that bubble entrapment is a common issue during
root-canal irrigation. Recent studies have also confirmed that surfactants do not enhance the ability of
NaOCl to dissolve pulp tissue (Clarkson et al. 2012;
Jungbluth et al. 2012) or the ability of common chelators to remove calcium from dentine (Zehnder et al.
2005) or to remove the smear layer (Lui et al. 2007;
De-Deus et al. 2008).
Syringes of variable capacity, ranging from 1 to
10ml (Abou-Rass & Piciccino 1982; Kahn et al. 1995;
Ram 1977; Moser & Heuer 1982; Chow 1983; Sabins
et al. 2003; Lee et al. 2004; Sedgley et al. 2005), have
been used. Although little attention has been given to
the size of the syringe, it can affect the force needed
to irrigate at a certain flow rate (Boutsioukis et al.
2007a). The flow rate is defined as the volume of irri-

gant delivered per unit time. (Mott 1999). A common
error among clinicians, which is also reproduced in
several irrigation studies, is that delivery of the irrigant at a high flow rate is erroneously termed “forceful delivery” or “delivery under pressure”. During syringe irrigation, a clinician applies force to the plunger
of the syringe. This force is transmitted to the irrigant
in the syringe, where pressure builds up. A
clinician will need to apply different amounts of force
and will feel different levels of difficulty in pushing
the plunger when syringes of different size are used,
even if the pressure actually developed is identical
(Tilton 1999). Larger syringes are more difficult to
depress. Hence, the clinician cannot draw reliable
conclusions about the pressure.

I

Fig. 4_Triads of time-averaged
contours (left), vectors (middle) of
velocity and streamlines (right) in the
apical part of the root canal for a
closed-ended (top) and open-ended
needle (bottom) positioned at 1 to
5mm short of WL, respectively.
Needles are coloured in red.
(Reprinted with permission from
Boutsioukis et al. 2010c.)

Fig. 4

The pressure difference between the syringe and
the tip of the needle is the cause of irrigant flow from
the syringe through the needle and into the root
canal. Irrigant flow rate is proportional to this difference, but is also affected by the size of the needle and
several other parameters (Tilton 1999). Therefore, for
the same pressure difference, the flow through a
smaller needle will be much less than through a larger
needle. Therefore, irrigant flow is not described accurately either by the force of the clinician or by the
pressure developed in the syringe, but by the flow
rate of the irrigant (Boutsioukis et al. 2007a, 2009),
which can also be estimated clinically. A 5ml syringe

roots
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[26] => RO0110_01_Titel

I research _ irrigation
In order to increase the efficiency of syringe irrigation, different needle types have been proposed
(Moser & Heuer 1982; Kahn et al. 1995; Yamamoto et
al. 2006; Vinothkumar et al. 2007; Boutsioukis et al.
2010b; Shen et al. 2010; Fig. 2). The type of the needle
has a significant effect on the flow pattern developed
(Fig. 3), while other parameters such as needle insertion depth, root-canal size and taper have only a limited influence (Boutsioukis et al. 2010a, 2010b, 2010c,
2010d, 2010e). Based on the resulting flow, the available needle types can be categorised into two main
groups, namely closed-ended and open-ended (Boutsioukis et al. 2010b). Both needle groups create a jet at
their outlet, but the shape of the outlet determines
the orientation and, to some extent, the intensity of
the jet.

Fig. 5

Fig. 5_Time-averaged distribution of
shear stress on the root-canal wall in
the apical part of a size 45 root canal
with a 0.06 taper during syringe irrigation using various needle types:
open-ended (A–C), closed-ended (D
& E). Only half of the root-canal wall
is presented to allow simultaneous
evaluation of the needle position.
Needles are coloured in red.
(Reprinted with permission from
Boutsioukis et al. 2010b.)

26 I roots
4_ 2012

combined with a 30G needle may be a reasonable
compromise between effectiveness, ease of use and
less frequent refilling, and can be used to reach flow
rates of up to 0.20 to 0.25ml/s (Boutsioukis et al.
2007a). High pressures may develop within the syringe during irrigation, so a Luer-lock connector is
always necessary to avoid sudden detachment of the
needle.
When investigating irrigation, it should be emphasised that the root canal behaves mostly like a
closed-end system, thus in most cases the apical
foramen should be considered non-patent (Hockett
et al. 2008; Boutsioukis et al. 2009; Bronnec et al.
2010a; Parente et al. 2010; Tay et al. 2010). The apex
being closed results in a significantly more complicated flow pattern compared with a simple tube
open from both sides, even if we consider a simplified
root-canal shape (White 1999; Boutsioukis et al.
2010a; Verhaagen et al. 2012). For very low flow rates,
in the order of 0.01 ml/s, a steady laminar flow is developed within the root canal (Boutsioukis et al.
2009; Verhaagen et al. 2012). For higher flow rates,
the flow becomes unsteady (changing as a function
of time) but remains laminar up to a flow rate of approximately 0.26ml/s (Boutsioukis et al. 2009, 2010a;
Verhaagen et al. 2012). For higher flow rates, turbulence may develop in some areas of the root canal,
mainly close to the tip of the needle, where irrigant
velocity is higher (Boutsioukis et al. 2009).

In the case of open-ended needles (flat, bevelled,
notched), the jet is very intense and extends along the
root canal to their tip. Within a certain distance, which
also depends on the geometry of the root canal and
the insertion depth of the needle, the jet appears to
break up gradually. Reverse flow towards the canal
orifice occurs near the canal wall. The jet formed by
the flat and bevelled needle is slightly more intense
and extends farther apically than the notched needle.
The overall performance of the bevelled and the
notched needle is slightly inferior to that of the flat
needle. Furthermore, the bevelled needle was originally designed for injections and its sharp tip poses a
significant risk of injury to both the patient and the
dentist, combined with an increased possibility of
wedging inside the root canal, so it should not be used
for root-canal irrigation (Boutsioukis et al. 2010b).
In the case of closed-ended needles (side-vented,
double side-vented), the jet of irrigant is formed near
the apical side of the outlet (the one proximal to the
tip for the double side-vented needle) and is directed
apically with a small divergence. The irrigant mainly
follows a curved path around the tip and then towards the coronal orifice. A series of counter-rotating
vortices (rotating flow structures) are formed apical
to the tip. Their size, position and number may differ
according to needle insertion depth, root-canal size
and taper, and flow rate. The velocity of the irrigant
inside each vortex decreases significantly towards
the apex. The distal outlet of the double side-vented
needle has only a minor influence on the overall flow
pattern because most of the irrigant flows out
through the proximal outlet, so it provides no significant advantage (Boutsioukis et al. 2010b). Contrary
to previous reports (Kahn et al. 1995), turbulence is
not developed at flow rates up to 0.26ml/s, but it may
develop at higher, clinically unrealistic flow rates
(Boutsioukis et al. 2009, 2010a; Verhaagen et al. 2012).
It is possible that formation of vortices and unsteady
flow were mistaken for turbulence in the past.

[27] => RO0110_01_Titel

FDI 2013 Istanbul

Annual World Dental Congress
28 to 31 August 2013 - Istanbul, Turkey

Bridging Continents for Global Oral Health

www.fdi2013istanbul.org
congress@fdi2013istanbul.org

[28] => RO0110_01_Titel

I research _ irrigation
Table 1_Medical needle
specifications according to
ISO 9626:1991/Amd.1:2001 and
corresponding size of endodontic
instruments according to ISO 36301:2008. (Non-existing instrument
sizes were rounded up to the next
available size.) Even if the nominal
size of an instrument and a needle
are the same, the actual sizes may
differ to some extent owing to
inevitable variations during the
machining procedures (tolerance).

ISO 9626:1991/Amd.1:2001
(Medical needles)
Gauge size

Designated
Metric size
(mm)

External
diameter (mm)

ISO 3630-1:2008
(Endodontic instruments)
Internal
diameter (mm)

min

max

min

max

0.80

0.800

0.830

0.490

80

0.760

0.840

23

0.60

0.600

0.673

0.317

60

0.580

0.620

25

0.50

0.500

0.530

0.232

50

0.480

0.520

27

0.40

0.400

0.420

0.184

40

0.380

0.420

28

0.36

0.349

0.370

0.133

40

0.380

0.420

29

0.33

0.324

0.351

0.133

35

0.330

0.370

30

0.30

0.298

0.320

0.133

30

0.280

0.320

31

0.25

0.254

0.267

0.114

25

0.230

0.270

Assuming other parameters are kept constant,
the use of a larger needle would result in a decrease
in the space available for irrigant flow between the
needle and the root-canal wall. This decrease has been
associated with either increased apical pressure for
open-ended needles or decreased irrigant refreshment apical to the tip for closed-ended needles, as will
be explained below in the relevant sections (Boutsioukis et al. 2010d, 2010e). Therefore, the use of a
larger needle would not provide any advantage, apart
from decreasing the clinician’s effort in pushing the
syringe plunger (Boutsioukis et al. 2007a).
The effect of tooth orientation (mandibular, maxillary, horizontal) on irrigant flow has been found to
result in only minor differences in the resulting flow
(Boutsioukis 2010; Boutsioukis et al. 2010a, 2010b). In

4_ 2012

min

21

Irrigation needles are available in various sizes,
which are most frequently described by the gauge
system (Boutsioukis et al. 2007b). These units are not
directly comparable to clinically related units like the
size of endodontic files and obturation materials;
thus, an intermediate conversion to millimetres may
be useful (Table 1). In the past, large needles (21–25G)
were commonly employed (Brown & Doran 1975;
Ram 1977; Salzgeber & Brilliant 1977; Chow 1983;
Teplitsky et al. 1987). Such needles could hardly penetrate beyond the coronal third of the root canal, even
in wide root canals. More recently, the use of finerdiameter needles (28 or 30G) has been advocated
(Sedgley et al. 2004; Zehnder 2006; Huang et al. 2008;
Bronnec et al. 2010b), mainly because they can reach
farther into the canal, even to working length (WL),
and thus may result in better irrigant exchange and
cleaning (Ram 1977; Chow 1983; Druttman & Stock
1989), but also because they may be more effective
than larger-diameter needles even when positioned
at the same depth (Chow 1983; Bronnec et al. 2010b).

28 I roots

Size

Tip diameter
(mm)

a single-phase system, such as a root canal completely filled with the irrigant, gravity affects the flow
through hydrostatic pressure. The latter is very low
compared with the dynamic pressure developed
owing to the flow of the irrigant. A noteworthy case
in which tooth orientation may be important is when
an air bubble is trapped in the apical part of the root
canal (apical vapour lock), so a two-phase system is
created (air and irrigant; De Gregorio et al. 2009; Tay
et al. 2010; Vera et al. 2011, 2012). The air bubble could
block irrigant penetration and, since air has a lower
density than irrigants, it would tend to remain apical
in a maxillary oriented root canal, if undisturbed,
owing to buoyancy. However, routine trapping of air
bubbles in the apical part of the root canal during
endodontic treatment has not been shown and
remains a speculation.

_Irrigant refreshment
Irrigant exchange in the various parts of the rootcanal system is a crucial requirement for ensuring
adequate chemical effect, since irrigants are rapidly
inactivated when they come into contact with tissue
remnants or microbes (Moorer & Wesselink 1982;
Druttman & Stock 1989; Haapasalo et al. 2005).
Needle type appears to have a significant effect on
the extent of apical irrigant exchange. Earlier reports
argued that closed-ended needles are more efficient
than open-ended ones (Kahn et al. 1995; Vinothkumar et al. 2007). However, recent studies have clarified the limitations in the irrigant refreshment apical
to closed-ended needles and clearly proven their
inferiority (Zehnder 2006; Boutsioukis et al. 2009,
2010b, 2010c, 2010d, 2010e; Verghaagen et al. 2012)
No significant difference has been detected between
various types of closed-ended needles or between
various types of open-ended needles (Vinothkumar
et al. 2007; Boutsioukis et al. 2010b).

[29] => RO0110_01_Titel

research _ irrigation

A general trend has been well documented in the
literature: needle placement closer to WL results in
more efficient irrigant exchange, regardless of needle type (Chow 1983; Sedgley et al. 2005; Hsieh et al.
2007; Boutsioukis et al. 2010c; Bronnec et al. 2010b;
Fig. 4). An increase in the preparation size or taper
allows penetration of the needle closer to WL (AbouRass & Piccinino 1982) and leads directly to more
efficient irrigant refreshment (Chow 1983; Falk &
Sedgley 2005; Hsieh et al. 2007; Huang et al. 2008;
Bronnec et al. 2010a; Boutsioukis et al. 2010d,
2010e). It seems that enlargement to size 25 does
not allow effective irrigant flow and apical refreshment even in 0.06 tapered root canals (Hsieh et al.
2007; Boutsioukis et al. 2010d). Enlargement to size
30 allows effective replacement 2mm apical to an
open-ended needle when combined with at least a
0.06 taper (Boutsioukis et al. 2010e), while size 35
combined with a 0.05 to 0.06 taper leads to significant irrigant refreshment almost 3mm apical to
the needle tip (Hsieh et al. 2007; Boutsioukis et al.
2010d). For closed-ended needles, it appears that irrigant replacement extends almost 1mm apical to
their tip in a root canal of size 30 and at least a 0.06
taper, while a further increase in the size or taper has
only a minimal additional effect (Hockett et al. 2008;

Boutsioukis et al. 2010d, 2010e). Therefore, these
needles should be placed within 1mm from WL,
and a minimum apical size of 35 is required in order
for a 30G needle to reach this depth. Surprisingly,
a minimally tapered root-canal preparation (size
60 and 0.02 taper) may present an advantage over
tapered ones in terms of irrigant refreshment (Boutsioukis et al. 2010e). However, irrigant exchange
should be evaluated together with resistance to root
fracture, the possibility of iatrogenic root-canal
perforation and obturation technique requirements
before deciding the instrumentation strategy.
Apart from the need to enlarge the root canal
so that the needle can reach within a few millimetres of WL, it is equally important to ensure adequate
space around the needle for reverse flow of the irrigant towards the canal orifice. Assuming that the
position and size of the needle remain constant, an
increase in the apical size or taper of the root canal
results in an increase in the space available between
the needle and the root-canal wall. This increase
leads to an increase in the irrigant refreshment in
the apical part of the root canal. Effective reverse
flow is also necessary for irrigant refreshment coronal to the needle tip (Boutsioukis et al. 2010d,
AD

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[30] => RO0110_01_Titel

I research _ irrigation
2010e). It has been speculated that a “dead-water”
zone or stagnation zone exists apical to the needle
tip (Gao et al. 2009; Shen et al. 2010). However,
recent studies have disproved this assumption and
have demonstrated that there are no areas in the
main root canal where the irrigant is completely
stagnant during syringe irrigation, but only areas
where the irrigant flow is extremely slow and adequate exchange cannot be ensured within the time
limitations of a root-canal treatment (Boutsioukis

Fig. 6

Fig. 6_Time-averaged irrigant pressure at the apical foramen for various
needle types: open-ended (A–C),
closed-ended (D & E). Data shown as
mean ± standard deviation.
(Reprinted with permission from
Boutsioukis et al. 2010b.)

et al. 2010a, 2010b, 2010c, 2010d, 2010e; Verhaagen et al. 2012). Increasing the volume of irrigant delivered could help to improve refreshment in
such cases (Sedgley et al. 2004, 2005; Bronnec et al.
2010b) because it can be translated into irrigating
for a longer time if the flow rate is constant.
Most of the data on irrigant flow and refreshment has been obtained from experiments and
simulations in simple, straight root canals; however,
many root canals are curved in reality. The effect of
curvature on irrigant exchange has been studied
indirectly by Nguy and Sedgley (2006), who reported
that only a severe curvature in the order of 24 to 28
degrees impeded the flow of irrigants, delivered by
a closed-ended needle near WL, even at a low flow
rate. It can be assumed that if needles are positioned
within 1 to 3mm short of WL in a curved root canal,
in many cases they have already bypassed most of
the curvature and the remaining curvature apical to
their tip is limited. Small size (30 G) flexible irrigation
needles available nowadays in the market facilitate
placement near WL, even in severely curved canals
provided that the canal is enlarged to at least a size
30 or 35.

30 I roots
4_ 2012

_Wall shear stress
During irrigant flow, frictional forces occur between
the flowing irrigant and root-canal walls. These forces
give rise to wall shear stress (Mott 1999; Tilton 1999;
White 1999), which is of particular interest to irrigation
because it tends to detach microbes/biofilm, tissue remnants or dentine debris from the root-canal wall; thus, it
determines the mechanical effect of irrigation. Currently,
there is no quantitative data on the minimum shear
stress required for the removal of these targets. However,
the overall distribution of wall shear stress provides an
indication of the mechanical debridement efficacy.
Similar to the irrigant flow, two basic wall shear
stress patterns can be distinguished for the various needle types during syringe irrigation (Fig. 5; Boutsioukis et
al. 2010b). Regarding open-ended needles, an area of increased shear stress (which can be linked to optimum
debridement) is developed apical to the needle tip, in the
region of jet break up. Closed-ended needles lead to almost twice as high maximum shear stress, but limited
near their tip, on the wall facing the needle outlet (the
proximal outlet for the double side-vented needle). The
unidirectional performance of closed-ended needles
has also been reported in ex vivo studies that documented the influence of needle orientation on the debridement of the root canal (Yamamoto et al. 2006;
Huang et al. 2008). So, in both cases, optimum debridement is expected near the tip of the needle (Huang et al.
2008; Boutsioukis et al. 2010b); therefore, during irrigation it is necessary to move the needle inside the root
canal, so that the limited area of high wall shear stress
affects as much of the root-canal wall as possible.
Needle insertion depth, canal size and taper do not
seem to affect the distribution of wall shear stress significantly (Boutsioukis et al. 2010c, 2010d, 2010e). The
maximum shear stress decreases as needles move away
from WL, or with increasing size or taper, because more
space is available for the back-flow of the irrigant and
the irrigant velocity decreases, but the area affected
by maximum shear stress becomes larger. It could be
hypothesised that over-enthusiastic enlargement of
the root canal beyond a certain size or taper may in fact
reduce the debridement efficacy of irrigation. Similar
to irrigant refreshment, it appears that the overall distribution of wall shear stress may be slightly more
favourable in canals with a large apical size and limited
taper rather than canals with a small size and increased
taper (Boutsioukis et al. 2010d, 2010e). No data is available on the effect of flow rate, but it can be assumed that
increasing the flow rate will also increase the wall shear
stress. In all cases, high shear stress may lead to the
detachment of biofilm or debris from the root-canal
wall but is not enough to ensure their removal from the
canal space, unless there is a favourable reverse flow to
carry them towards the canal orifice.

[31] => RO0110_01_Titel

research _ irrigation

_Apical pressure—Extrusion
During root-canal irrigation, it is possible that
part of the irrigant delivered will be extruded towards
the periapical tissue (Vande Visse & Brilliant 1975;
Hülsmann et al. 2009). A healthy periodontium seems
to provide a reliable barrier against irrigant extrusion
(Salzgeber & Brilliant 1977; Chu 2010). However,
currently, there is insufficient data to allow a more
elaborate understanding of this aspect of root-canal
irrigation. In order to conduct some useful comparisons, the irrigant pressure at the apical foramen
could be related to the possibility and severity of irrigant extrusion (Boutsioukis et al. 2010b).
In general, the open-ended needles achieve improved irrigant refreshment in the apical part of the
root canal but also lead to higher pressure at the apical foramen, indicating an increased risk of irrigant
extrusion; closed-ended needles develop much lower
pressure (approximately 50% less; Fig. 6; Boutsioukis et al. 2010b). Both needle types present a similar decrease in apical pressure, as the insertion depth
decreases or the preparation size or canal taper increases (Boutsioukis et al. 2010c, 2010d, 2010e).
The performance of open-ended and closed-ended
needles is expected to be quite different in the hypothetical situation of the needle binding in the root
canal. If an open-ended needle is used, the flow would
be trapped apical to the needle tip without any route
of escape towards the canal orifice, the apical pressure
would increase rapidly and forceful irrigant extrusion
would probably occur. To the contrary, binding of a
closed-ended needle would limit the irrigant flow to
the space coronal to its tip. Irrigant exchange apical to
the tip would be impossible, but the apical pressure
would be almost zero, which is a benefit of the blind tip
or safe tip of closed-ended needles, providing safety in
such cases (Boutsioukis et al. 2010d, 2010e).

trusion contradict each other and a delicate balance
needs to be maintained. Since the prevention of extrusion should precede the other requirements of irrigation, a reasonable compromise for open-ended
needles would be 2 or 3mm short of WL. Based on
Computational Fluid Dynamics analyses, this can still
ensure adequate irrigant exchange and high wall
shear stress, while reducing the risk of extrusion, provided that the canal is enlarged to at least a size 35
with a 0.06 taper or to a larger apical size combined
with a minimum taper. The development of lower irrigant pressure by closed-ended needles allows their
placement within 1mm short of WL, so that optimum
irrigant exchange can be ensured.
Anatomic irregularities may create additional
challenges. Syringe irrigation seems unable to prevent or remove hard-tissue debris from the isthmus
between the mesial root canals of mandibular molars
(Endal et al. 2011; Paqué et al. 2011) or from artificial
grooves and cavities in the apical part of the canal
(Rödig et al. 2010). Currently, the irrigant flow in such
complicated geometries has not been studied. It can
be speculated that flow into narrow spaces connected
to the main root canal is dependent on adequate
activation, which could force the irrigant laterally into
the grooves, cavities and isthmuses (Jiang et al. 2010),
while syringe irrigation is possibly unable to achieve
this goal predictably under clinical conditions.
In all cases, it must be remembered that regardless
of the method and equipment used, irrigation of root
canals involves a series of human-controlled actions,
inevitably prone to natural human variability and difficult to standardise on a clinical basis. A wide variation in irrigant flow rate, duration, volume of irrigant
and force applied to the syringe has been found
among endodontists, even when the participants
shared a common educational background (Boutsioukis et al. 2007a). Thus, the human factor should
also be considered in root-canal irrigation._

_Concluding remarks
Anatomical complexities of the root-canal system
and the existence of microbes as surface-adherent
biofilm structures serve as the foremost challenges in
root-canal disinfection. One way of circumventing
such challenges is by combining ideal irrigants with
an optimal irrigation technique to achieve maximum
removal of biofilms from the root canals. Accordingly,
it becomes imperative to understand the fluid dynamics of irrigation in the root-canal system. The application of Computational Fluid Dynamics (CFD) models provides information on the flow and exchange of
irrigant within the root-canal system for a particular
mode of irrigation. It appears that the requirements
of adequate irrigant penetration and exchange, mechanical debridement and minimum risk of apical ex-

Editorial note: A complete list of references is available from
the publisher.

_about the authors

roots

Dr Christos Boutsioukis
Physics of Fluids Group and MESA+ Institute for Nanotechnology, University of Twente, Enschede, and Department of Endodontology, Academic
Centre for Dentistry Amsterdam (ACTA), Amsterdam, The Netherlands.
Dr Anil Kishen
Discipline of Endodontics, Faculty of Dentistry,
University of Toronto, Toronto, Canada

roots
I 31
4
_ 2012

[32] => RO0110_01_Titel

I special topic _ irrigation

Irrigation for the root canal
and nothing but the root canal
Author_ Dr Philippe Sleiman, Lebanon

Fig. 1

Fig. 2

_Irrigation is a major step in endodontic treatment. A variety of chemicals are used to achieve
what I like to consider the chemical preparation of
the root-canal system.
Sodium hypochlorite (NaOCl) is a major component of the chemical preparation, mainly owing to its
ability to attack the collagen component of the pulp
tissue, and it is very cost-effective. However, one of
the problems of using NaOCl is its safety, especially
during its delivery inside the root-canal system and
the ability to limit its delivery strictly to root-canal
space and nothing but the root-canal space.
Going beyond the limit of the root-canal space
causes serious problems, the gravity of which depends
on the amount of NaOCl passing to the margins of the
periodontal ligament or even attacking the periodon-

Fig. 3

Fig. 4

32 I roots
4_ 2012

tal ligament. A small amount can result in pain or
discomfort after treatment, whereas a larger amount,
especially in cases of large and\or open apices, can
accidentally be delivered inside the maxillary bone,
travel via veins and arteries to primary anatomical organs and cause extensive, serious and very dangerous
reactions. It is possible that the majority of such incidents are treatable with steroids and antibiotics, as
they are limited to muscle and bone inflammation and
slight reversible necrosis.
Sometimes we are not that lucky. Irrigating the last
few millimetres in the root-canal space is an important
key to treatment success, and a certain amount of
NaOCl may be delivered into the maxillary sinus especially in the area of the maxillary second premolar and
first molar. The case discussed below was the result of
accidental NaOCl delivery into the maxillary sinus.

Fig. 5

[33] => RO0110_01_Titel

special topic _ irrigation

_Case report
The patient was referred to my office for a complaint regarding the maxillary molar. After examining
the patient and looking at her preoperative X-ray,
I saw nothing wrong with the existing root-canal
treatment, at least concerning the roots, but found
a vague image in the sinus that I thought could be
related to the maxillary molar and could be the cause
of the problem. I asked my assistant to take a panoramic X-ray, which demonstrated a much larger problem inside the sinus but at that point I did not realise
the scale of the issue.
Turning back to the patient, I went into some
questions related to the issue, such as “Do you have
problems breathing through your nose on this side?”,
“Can you describe to me the pain or discomfort you
are having?”, “Can you tell me if anything unusual
happened during your previous root-canal treatment?” and “What were the indications for this treatment several months before?”. The patient, quite unexpectedly, told me that during the procedure she
had had a chlorine taste in her throat arising from her
nose as if a liquid was dripping internally. Also, after
the treatment was over and she was on her way home,
a strange liquid with the same chlorine smell began
dripping from her nose.
Upon hearing that, I asked the patient to have a
CBCT scan of the maxilla because it was necessary to
establish the situation in the sinus. The patient was
nervous and anxious, so I asked the radiology centre
if they could capture the CBCT scan for her on the
same day as a favour.
A couple of hours later, the patient returned to
my office and I took the time to examine the images. In
the panoramic view, it was clear that half of the
sinus was filled with inflammatory tissue (Fig. 2); in the
sectional views, I noticed that the posterior wall of the
sinus was non-existent in some places (Figs. 3–5). Potentially, it could be the position of the patient during
the root-canal procedure that made NaOCl stagnate
on the posterior wall and aggravate the damage.
The patient was informed of my opinion and recommended to see her otorhinolaryngologist, who
took over the case, since it was already beyond the
specialty of the dental profession and so she did.

_Conclusion
As we have seen, what seems to be a normal rootcanal treatment can hold serious implications for
human health. Although it is very true that we need
irrigation to clean the root-canal system, those
chemicals need to be limited to the root-canal system

Fig. 6

only, as even a few drops of NaOCl approaching the
periodontal ligament may create an inflammatory
region and area of tissue damage as a result of an
aggressive chemical reaction.
Sometimes this process is limited and may only
cause minor discomfort for a couple of days, but
when the amount of chemical is larger more severe
problems may occur, for which the use of steroids and
antibiotics is recommended. A major accident can still
happen at any time when an amount of chemical
travels outside the oral cavity and causes a more
serious complication.
One of the safest options that we currently have
at our disposal is the EndoVac system (SybronEndo),
which is designed specifically to deliver fresh irrigant
all along the root-canal system and, most importantly,
to clean the last 3mm of the root-canal system using
the MicroCannula. It allows us to be certain that no
chemicals can go beyond the limits of the root-canal
space, nor cause any serious or even minor damage._
I would like to thank Yulia Vorobyeva, interpreter
and translator, for her help with this article.

_contact

roots

Dr Philippe Sleiman
Dubai Sky Clinic
Level 21 Burjuman Business Tower
Trade Center St.
Bur Dubai
Dubai
UAE
phil2sleiman@hotmail

roots
I 33
4
_ 2012

[34] => RO0110_01_Titel

I case report _ treatment of taurodontic teeth

Endodontic management
of a hypertaurodontic
maxillary first molar—
A case report with a two-year follow-up
Authors_ Drs Jojo Kottoor, Denzil Valerian Albuquerque, Anuj Bhardwaj, Sonal Dham & Natanasabapathy Velmurugan, India

_Introduction
Taurodontism is a morphological variation in which
the body of the tooth is enlarged and the roots are reduced in size. Taurodontic teeth have large pulp chambers and apically positioned furcation.1 This variation
was first described by Gorjanović-Kramberger;2 however, the term “taurodontism” was first introduced by
Sir Arthur Keith3 to describe molar teeth resembling
those of ungulates, particularly bulls. The term “taurodontism” comes from the Latin term “tauros”, which
means “bull” and the Greek term “odus”, which means
“tooth” or “bull tooth”.4 Such morphological variations
are an endodontic challenge and even more difficult to
treat when additional roots and/or canals are present.
The endodontic management of one such taurodontic
molar is reported in this case report.

(tooth #16). The preoperative periapical radiograph
(Fig. 1a) suggested the following possibilities:
_a mesio-occlusal carious lesion with endodontic involvement;
_a highly calcified and elongated pulp chamber extending up to the trifurcation;
_three short roots with the trifurcation in the apical
third; or
_a periapical radiolucency in relation to the mesiobuccal and palatal root apex.
Clinically, vitality tests were negative and a diagnosis of hypertaurodontism, according to Shifman
and Chanannel,5 with pulpal necrosis was made for
tooth #16 and endodontic treatment was planned.

A 44-year-old male patient was referred to our
clinic for treatment of the right maxillary first molar

Local anaesthesia of 2% lidocaine with 1:100,000
epinephrine was administered to the patient. The
mesial surface of the tooth was restored with composite resin (Z100, 3M ESPE) after caries excavation
to enable optimal isolation. Under rubber dam isola-

Fig. 1a

Fig. 1b

_Case report

Fig. 1a_Diagnostic radiograph
of tooth #16 demonstrating
hypertaurodontism and coronal
pulp chamber obliteration.
Fig. 1b_Initial working length
radiograph with three canals
located.

34 I roots
4_ 2012

[35] => RO0110_01_Titel

case report _ treatment of taurodontic teeth

Fig. 1c_Post-op radiograph with a
coronal filling.
Fig. 1d_Working length radiograph
after re-entry into the tooth, showing
the additional mesiobuccal canal.

Fig. 1c

Fig. 1d

tion, the access cavity was established with an Endo
Access bur and an Endo Z bur (DENTSPLY Tulsa). A
dental operating microscope (DOM; Seiler Revelation)
was used throughout the procedure to facilitate
visualisation. The calcified mass occluding the pulp
chamber was removed using ET 18D ultrasonic tips
(Satelec/Acteon). Three root-canal orifices were located: two narrow orifices, the mesiobuccal and
distobuccal, and a wide palatal orifice. Root-canal
orifices were named according to the nomenclature
proposed by Kottoor et al.5 An electronic apex locator
(Root ZX, Morita) was used to determine the initial
working length, which was confirmed radiographically (Fig. 1b). The root canals were cleaned and
shaped with ProTaper (DENTSPLY Maillefer) rotary instruments. The buccal canals were instrumented up to
F2 and palatal canal to F4. The canals were irrigated
with 2.5% sodium hypochlorite using ultrasonics,
17% aqueous solution of EDTA, and 0.2% w/v
chlorhexidine gluconate. The canals were dried using
sterile paper points and obturated with gutta-percha
cones and AH Plus sealer (DENTSPLY DeTrey) using the
cold lateral compaction and vertical compaction
techniques. The access cavity was then restored with
miracle mix (cermet and Ketac Silver, 3M ESPE; Fig. 1c).

under the DOM revealed a second mesiobuccal canal
(P-MB). Under the microscope, it was possible to insert a #15 K-file and the existence of the additional
canal was confirmed using an electronic apex locator.
A working length radiograph was taken with a #20 Kfile in the untreated canal (Fig. 1d). The P-MB canal
was instrumented to F2 under irrigation with 3%
sodium hypochlorite and EDTA and obturated by cold
lateral compaction of the gutta-percha and AH Plus
sealer (Fig. 1e). Follow-up clinical examination after a
week revealed that the tooth was asymptomatic and
was not sensitive to percussion or palpation. Subsequently, endodontic management of tooth #15 was
completed. The 24-month follow-up radiograph
showed complete resolution of the periapical radiolucency in relation to the mesiobuccal and palatal
root apices (Fig. 1f).

The patient returned to the endodontic clinic
after three weeks with sensitivity in the same tooth on
consumption of cold foods. The longevity of the complaint prompted a re-entry into the tooth to evaluate
the possibility of any additional canal/s. The coronal
restoration was removed and the pulpal floor was
carefully inspected again under the DOM at a higher
magnification. The visual and tactile examination

_Discussion
Taurodontism is frequently associated with other
anomalies and syndromes. These include Klinefelter
syndrome,6 ectodermal alterations,7 Down syndrome,8
Mohr syndrome,9 Wolf-Hirschhorn syndrome,10
Lowe syndrome,11 Tricho-dento-osseous syndrome,12
Williams syndrome,13 and Seckel syndrome,14 but it is
not a constant feature of these syndromes.15 However,
identification of patients with multiple taurodontic
teeth could lead to early recognition of a systemic
disorder and improve quality of life. It has also been
found to be associated with dental anomalies such as
oligodontia, supernumerary teeth, and amelogenesis
imperfecta.16 In this case, the patient was a healthy
male with a negative medical history.
Figs. 1e & f_Immediate post-op
radiograph (e) and follow-up
radiograph at 24 months, showing
periapical healing (f).

Fig. 1e

Fig. 1f

roots
I 35
4
_ 2012

[36] => RO0110_01_Titel

I case report _ treatment of taurodontic teeth
Its aetiology is still unknown, but it has been
suggested that it may be caused by a failure of the
diaphragm of Hertwig’s epithelial root sheath to
invaginate at the correct time and horizontal level
or changes in the mitotic activity of cells of the
developing teeth that can affect root formation or
influence by external factors on the development
of the teeth.18 Differences in opinion exist regarding the amount of displacement and/or morphological change required to constitute taurodontism. Based on the relative amount of apical
displacement of the pulp chamber floor, Shaw19
classified taurodontism as hypotaurodontism,
mesotaurodontism, and hypertaurodontism. This
subjective, arbitrary classification led normal teeth
to be misdiagnosed as taurodontism. Feichtinger
and Rossiwall20 state that the distance from the
bifurcation or trifurcation of the root to the cemento-enamel junction should be greater than the
occluso-cervical distance for a taurodontic tooth.
Keene21 proposed the Taurodont Index, relating the
height of the pulp chamber to the length of the
longest root. Although there are many classification systems to determine the severity of taurodontism,22 the classification proposed by Shifman and
Chanannel15 in 1978 is the most widely used system. According to this index, taurodontism is present if the distance from the lowest point at the
occlusal end of the pulp chamber to the highest
point at the apical end of the chamber, divided by

_about the authors

roots

Dr Jojo Kottoor
He is the first author worldwide to have reported seven and
eight root canals in a maxillary molar. His work consequently
made the cover page of the Journal of Endodontics. He has a
special interest in root-canal anatomy and is currently a Associate Professor in conservative dentistry and endodontics at
Mar Baselios Dental College in Kochi, India.
Dr Denzil Valerian
Albuquerque is a
Associate Professor
at Terna Dental College and Hospital in
Navi Mumbai, India.

Dr Anuj Bhardwaj
is a Endodontist
at Bhardwaj Dental
Clinic in Indore,
India.

Dr Sonal Dham
is a Associate Professor at Guru Teg
Bahadur Hospital in
New Delhi, India.

Dr Natanasabapathy Velmurugan
is a Professor and
Head at Meenakshi
Ammal Dental
College in Chennai,
India.

36 I roots
4_ 2012

the distance from the occlusal end of the pulp
chamber to the apex and multiplied by 100 is 20 or
above (hypotaurodontism: TI 20–30; mesotaurodontism: TI 30–40; hypertaurodontism: TI 40–75).
Except for a higher prevalence of taurodontism
among females in a Chinese sample,23 no study has
found a gender difference for this abnormality.
Although permanent mandibular molars are most
commonly affected,23 taurodontism is occasionally observed in mandibular premolars and even in
maxillary premolars, mandibular canines, and incisors.24–26 Its prevalence has been reported as ranging from 5.67 to 60 % of subjects.27, 28 In a recent
study, it accounted for 18 % of all anomalies.29
Endodontic treatment in taurodontic teeth
has been described as complex and challenging
because the apical position of the pulpal floor can
make it difficult to identify and locate root-canal
orifices. In the present case, an apical third trifurcation with four root canals was observed. The
mesiobuccal and distobuccal canal orifices were
very narrow and close to each other, which made
identification and negotiation of these orifices
very difficult. Additionally, the proximity of the
orifices and deeply situated opening of the canals
made it difficult to identify the P-MB during the
initial visit. However, during the second visit, the
use of DOM enhanced the visualisation of the
pulpal floor by better illumination of the depths of
the cavity. Hence, success was largely dependent
on the use of magnification, which allowed for
the identification of the P-MB canal with ease.
During instrumentation, the shortened length of
these canals allowed for instrumentation with
only the apical third of the file, also making it time
consuming. Thus, endodontic treatment of taurodontic teeth may be complex, particularly regarding
the cleaning and shaping of the root canals and
root-canal obturation, especially in hypertaurodontic teeth.

_Conclusion
The case report has described the successful
endodontic treatment of a hypertaurodontic maxillary first molar that would have seemed impossible to perform with conventional techniques. Success was mostly attributed to the use of magnification, which allowed better visualisation of the four
canal orifices. This case report has served to illustrate to clinicians that sound knowledge and modern equipment facilitate enhanced management of
endodontically challenging taurodontic teeth._
Editorial note: A complete list of references is available from
the publisher.

[37] => RO0110_01_Titel

Welcome
W
elcome
elcom to the 46th Scandinavian Dental Fair
The leading annual dental fair in Scandinavia

The 46th SCANDEF
SCANDEFA
ANDEF
FA
A invites you to exquisitely meet the Scandinavian dental market and
sales partners fr
from
om all over the world in springtime in wonderful Copenhagen
SCANDEF
SCANDEFA
FA 2013
20

Exhibit at Scandefa

Is organized by Bella Center
Center
and is being held in conjunction
with the Annual Scientific
Meeting, organized by the
Danish Dental Association
(www.tandlaegeforeningen.dk).
(www.tandlaegefor
forreningen.dk).

Book online at www
www.scandefa.dk
.scandefa.dk
Account
ccount Manager Tommy
Tommy Louens
tlo@bellacenter.dk,
tlo@bellacenter
o@bellacenterr.dk, T +45 32 47 21 33

183 exhibitors and 10.562
visitors participated at
SCANDEFA
approx.
SCANDEF
FA 2012 at appr
ox.
2
14,000 m of exhibition space.

Travel
T
r
ravel
information
Bella Center is located just
just aa 10
10 minute
minute taxi
taxi drive
drivefr
from
from Copenhagen
Airport. A rregional
egional train runs from
from the airport to Orestad
Orestad Station,
only 15 minutes drive.

Check in at Bella Center’
Center’s
s newly built hotel
Bella Sky Comwell is Scandinavia’
Scandinavia’s
s largest design hotel.
The hotel is an integral part of Bella Center and has dir
direct
re
ect
access to Scandefa. Book your stay on www
www.bellasky.dk
.bellasky.dk

w w w. scandefa.dk

Fotos from
from Bella Center
Center,, W
Wonderful
onderful Copenhagen

201
2013

[38] => RO0110_01_Titel

I industry news _ VDW

VDW Motors produced
in Tuscany, Italy
Since 2006 all VDW endo motors are being produced in Pistoia. From the start, the huge success of
these devices faced ATR with enormous challenges.
To satisfy the demand of many dentists, ATR's designers were soon able to solve the then problematic
integration of an apex locator into the endo motor.
They developed a patented in-house product, the
(VDW.GOLD). In 2010 VDW acquired 100% of ATR
which enabled them to introduce capital and knowhow to expand the urgently needed production capacities. At first VDW’s high standards of quality assurance were implemented step by step, which allowed
VDW to extend the warranty of new ATR devices to
3 years.

Fig. 1

Fig. 1_Quality assurance:
documentation of any step.
Fig. 2_VDW.SILVER RECIPROC,
VDW.GOLD RECIPROC.

roots

_contact
VDW GmbH
Bayerwaldstr. 15
81737 Munich
Germany

info@vdw-dental.com
www.vdw-dental.com

38 I roots
4_ 2012

_With their product lines VDW.SILVER and
VDW.GOLD, VDW—the specialist in endodontics, has
set standards in design, function and user-friendliness
of endo motors. In addition to controlling rotary NiTi
systems the current device series with the name
affix RECIPROC also masters the innovative reciproc
technique.
The motors are produced by ATR in Pistoia near
Florence, Italy. The company name stands for Advanced
Technology Research. From the beginning ATR has
specialised in micro-motors for dentistry. In 1999 the
then young company has developed the first endo
motor with torque control: the ATR TECNIKA. This first
motor, and more so the following model ATR VISION
were able to offer the user a wide range of applications, including programming individual drive modes
via the system menu. Contributions in internet
based forums still demonstrate that particularly the ATR motors have allowed to perform
trials with the Ghassan Yared technique (known
today as the reciproc technique).
A further pillar of the ATR production
is the division for powerful precision
motors for implantology, which are
well established in several markets.

The user-friendly reciproc drive with precise
control of the rotational angles was successfully
developed by ATR. In practice, the user does not need
to make any settings and can focus solely on the
treatment.
The concurrent increase of the production output
represented an enormous step. Compared to 2009,
eight times more motors are being produced today,
which corresponds to the actual peak
requirement. The modern VDW endo
motors with their functional design
are in high demand worldwide.
The current VDW.SILVER RECIPROC
motor is being sold in 64 countries.
This is a great success story for VDW
and ATR._

Fig. 2

[39] => RO0110_01_Titel

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[40] => RO0110_01_Titel

I meetings _ events

International Events
2013
Irish Endodontic Society Annual Scientific
Meeting
24–25 January 2013
Dublin, Ireland
www.irishendodonticsociety.com
DGET Spring Meeting
1 & 2 March 2013
Hanover, Germany
www.dget.de

International Dental Show
12–16 March 2013
Cologne, Germany
www.ids-cologne.de
35th Australian Dental Congress
3–7 April 2013
Melbourne, Australia
www.adc2013.com
3rd Russian Endodontic Congress
5–7 April 2013
Moscow, Russia
www.congress2013.endoforum.ru
AAE Annual Session
17–20 April 2013
Hawaii, USA
www.aae.org
CONSEURO Paris 2013
9–11 May 2013
Paris, France
www.paris2013.conseuro.org
FEA World Endodontic Congress
23–26 May 2013
Tokyo, Japan
www2.convention.co.jp/ifea2013
The international congress of the French Society
of Endodontic (FSE)
20–22 June 2013
Aix en Provence, France
www.endodontie.fr
FDI Annual World Dental Congress
28–31 August 2013
Istanbul, Turkey
www.fdiworldental.org
ESE Biennial Congress
12–14 September 2013
Lisbon, Portugal
www.e-s-e.eu

40 I roots
4_ 2012

[41] => RO0110_01_Titel

about the publisher _ submission guidelines

submission guidelines:
Please note that all the textual components of your submission
must be combined into one MS Word document. Please do not
submit multiple files for each of these items:
_the complete article;
_all the image (tables, charts, photographs, etc.) captions;
_the complete list of sources consulted; and
_the author or contact information (biographical sketch, mailing
address, e-mail address, etc.).

I

Image requirements
Please number images consecutively throughout the article
by using a new number for each image. If it is imperative that
certain images are grouped together, then use lowercase letters
to designate these in a group (for example, 2a, 2b, 2c).
Please place image references in your article wherever they
are appropriate, whether in the middle or at the end of a sentence.
If you do not directly refer to the image, place the reference
at the end of the sentence to which it relates enclosed within
brackets and before the period.
In addition, please note:

In addition, images must not be embedded into the MS Word
document. All images must be submitted separately, and details
about such submission follow below under image requirements.
Text length
Article lengths can vary greatly—from 1,500 to 5,500 words—
depending on the subject matter. Our approach is that if you
need more or less words to do the topic justice, then please make
the article as long or as short as necessary.
We can run an unusually long article in multiple parts, but this
usually entails a topic for which each part can stand alone because it contains so much information.
In short, we do not want to limit you in terms of article length,
so please use the word count above as a general guideline and if
you have specific questions, please do not hesitate to contact us.
Text formatting
We also ask that you forego any special formatting beyond the
use of italics and boldface. If you would like to emphasise certain
words within the text, please only use italics (do not use underlining or a larger font size). Boldface is reserved for article headers.
Please do not use underlining.
Please use single spacing and make sure that the text is left justified. Please do not centre text on the page. Do not indent paragraphs, rather place a blank line between paragraphs. Please do
not add tab stops.

_We require images in TIF or JPEG format.
_These images must be no smaller than 6 x 6 cm in size at 300 DPI.
_These image files must be no smaller than 80 KB in size (or they
will print the size of a postage stamp!).
Larger image files are always better, and those approximately
the size of 1 MB are best. Thus, do not size large image files down
to meet our requirements but send us the largest files available.
(The larger the starting image is in terms of bytes, the more leeway the designer has for resizing the image in order to fill up more
space should there be room available.)
Also, please remember that images must not be embedded into
the body of the article submitted. Images must be submitted
separately to the textual submission.
You may submit images via e-mail, via our FTP server or post
a CD containing your images directly to us (please contact us
for the mailing address, as this will depend upon the country from
which you will be mailing).
Please also send us a head shot of yourself that is in accordance
with the requirements stated above so that it can be printed with
your article.
Abstracts
An abstract of your article is not required.

Should you require a special layout, please let the word processing
programme you are using help you do this formatting automatically. Similarly, should you need to make a list, or add footnotes
or endnotes, please let the word processing programme do it for
you automatically. There are menus in every programme that will
enable you to do so. The fact is that no matter how carefully done,
errors can creep in when you try to number footnotes yourself.

Author or contact information
The author’s contact information and a head shot of the author
are included at the end of every article. Please note the exact
information you would like to appear in this section and format it according to the requirements stated above. A short
biographical sketch may precede the contact information
if you provide us with the necessary information (60 words
or less).

Any formatting contrary to stated above will require us to remove
such formatting before layout, which is very time-consuming.
Please consider this when formatting your document.

Questions?
Magda Wojtkiewicz (Managing Editor)
m.wojtkiewicz@oemus-media.de

roots
I 41
4
_ 2012

[42] => RO0110_01_Titel

I about the publisher _ imprint

roots
international magazine of

endodontology

Publisher
Torsten R. Oemus
oemus@oemus-media.de

CEO
Ingolf Döbbecke
doebbecke@oemus-media.de

Published by
Oemus Media AG
Holbeinstraße 29
04229 Leipzig, Germany
Tel.: +49 341 48474-0
Fax: +49 341 48474-290
kontakt@oemus-media.de
www.oemus.com

Magda Wojtkiewicz, Managing Editor

Printed by
Members of the Board
Jürgen Isbaner
isbaner@oemus-media.de
Lutz V. Hiller
hiller@oemus-media.de

Managing Editor
Magda Wojtkiewicz
m.wojtkiewicz@oemus-media.de

Executive Producer
Gernot Meyer
meyer@oemus-media.de

Designer
Josephine Ritter
j.ritter@oemus-media.de

Copy Editors
Sabrina Raaff
Hans Motschmann

Löhnert Druck
Handelsstraße 12
04420 Markranstädt, Germany

Editorial Board
Fernando Goldberg, Argentina
Markus Haapasalo, Canada
Ken Serota, Canada
Clemens Bargholz, Germany
Michael Baumann, Germany
Benjamin Briseno, Germany
Asgeir Sigurdsson, Iceland
Adam Stabholz, Israel
Heike Steffen, Germany
Gary Cheung, Hong Kong
Unni Endal, Norway
Roman Borczyk, Poland
Bartosz Cerkaski, Poland
Esteban Brau, Spain
José Pumarola, Spain
Kishor Gulabivala, United Kingdom
William P. Saunders, United Kingdom
Fred Barnett, USA
L. Stephan Buchanan, USA
Jo Dovgan, USA
Vladimir Gorokhovsky, USA
James Gutmann, USA
Ben Johnson, USA
Kenneth Koch, USA
Sergio Kuttler, USA
John Nusstein, USA
Ove Peters, USA
Jorge Vera, Mexico

Copyright Regulations
_roots international magazine of endodontology is published by Oemus Media AG and will appear in 2012 with one issue every quarter. The magazine
and all articles and illustrations therein are protected by copyright. Any utilisation without the prior consent of editor and publisher is inadmissible and liable
to prosecution. This applies in particular to duplicate copies, translations, microfilms, and storage and processing in electronic systems.
Reproductions, including extracts, may only be made with the permission of the publisher. Given no statement to the contrary, any submissions to the
editorial department are understood to be in agreement with a full or partial publishing of said submission. The editorial department reserves the right to
check all submitted articles for formal errors and factual authority, and to make amendments if necessary. No responsibility shall be taken for unsolicited
books and manuscripts. Articles bearing symbols other than that of the editorial department, or which are distinguished by the name of the author, represent
the opinion of the afore-mentioned, and do not have to comply with the views of Oemus Media AG. Responsibility for such articles shall be borne by the author.
Responsibility for advertisements and other specially labeled items shall not be borne by the editorial department. Likewise, no responsibility shall be assumed
for information published about associations, companies and commercial markets. All cases of consequential liability arising from inaccurate or faulty
representation are excluded. General terms and conditions apply, legal venue is Leipzig, Germany.

42 I roots
4_ 2012

[43] => RO0110_01_Titel

You can also subscribe via
www.oemus.com/abo

would like to subscribe to
for € 44 including
shipping and VAT for German customers, € 46 including
shipping and VAT for customers outside Germany, unless
a written cancellation is sent within 14 days of the
receipt of the trial subscription. The subscription will
be renewed automatically every year until a written
cancellation is sent to OEMUS MEDIA AG, Holbeinstr. 29,
04229 Leipzig, Germany, six weeks prior to the renewal date.

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Reply via Fax to +49 341 48474-290 to

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OEMUS MEDIA AG or via E-mail to
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Notice of revocation: I am able to revoke the subscription within 14 days after my order by sending a written cancellation to OEMUS MEDIA AG, Holbeinstr. 29, 04229 Leipzig, Germany.

Signature

roots 4/12

Signature

OEMUS MEDIA AG
Holbeinstraße 29, 04229 Leipzig, Germany, Tel.: +49 341 48474-0, Fax: +49 341 48474-290, E-mail: grasse@oemus-media.de

[44] => RO0110_01_Titel

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