Implant Tribune UK No. 1, 2014

Single molar restoration — Wide implant versus two conventional / Time proven clinical success of the SHORT™ implant / Stem cells in implant dentistry

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Implant Tribune
Implant Tribune

Implant Tribune

Short™ Implants

Stem cells in implant dentistry

Prof Marincola et al discuss short implants

Dr Pelegrine discusses the benefits of stem call therapy

pages 15-17

pages 18-20

Single molar restoration —Wide
implant versus two conventional
Prof Amr Abdel Azim, Dr Amani M Zaki & Dr Mohamed I El-Anwar

Fig 1

Fig 2

Fig 4b

T

he single-tooth restoration has become one of
the most widely used procedures in implant dentistry.1 In
the posterior region of the oral
cavity, bone volume and density
are often compromised. Occlusal
forces are greater in this region
and, with or without parafunctional habits, can easily compromise the stability of the restorations (Fig. 1). 2, 3

The single-molar implantsupported restoration has historically presented a challenge in
terms of form and function. The
mesiodistal dimensions of a molar exceed that of most standard

Fig 3

Fig 4a

Fig 4c

implants (3.75 to 4.0 mm), creating the possibility of functional
overload resulting in the failure
of the retaining components or
the failure of the implant (Figs.
2 & 3).4 Wider-diameter implants
have a genuine use in smaller
molar spaces (8.0 to 11.0mm)
with a crestal width greater than
or equal to 8mm (Fig. 4 a).5 Clinical parameters governing the
proposed restoration should be
carefully assessed in light of the
availability of implants and components that provide a myriad
of options in diameter, platform
configurations and prosthetic
connections. Many of the newer
systems for these restorations are

showing promising results in recent clinical trials.6-8 It has further
been suggested by Davarpanah
and others,9 Balshi and others,2
English and others10 and Bahat
and Handelsman11 that the use
of multiple implants may be the
ideal solution for single-molar
implant restorations (Figs. 4 b &
c).
Most standard implants and
their associated prosthetic components, when used to support
a double implant molar restoration, will not fit in the space occupied by a molar unless the space
has been enlarged (12mm or
larger).4 Moscovitch suggests that

the concept of using 2 implants
requires the availability of a
strong and stable implant having
a minimum diameter of 3.5 mm.
Additionally, the associated prosthetic components should ideally
not exceed this dimension.2
Finite element analysis (FEA)
is an engineering method that
allows investigators to assess
stresses and strains within a solid
body.10-13 FEA provides calculation of stresses and deformations of each element alone and
the net of all elements. A finite
element model is constructed
by breaking a solid object into a
number of discrete elements that

are connected at common nodal
points. Each element is assigned
appropriate material properties
that correspond to the properties of the structure to be modelled. Boundary conditions are
applied to the model to stimulate
interactions with the environment.14 This model allows simulated force application to specific
points in the system, and it provides the resultant forces in the
surrounding structures. FEA is
particularly useful in the evaluation of dental prostheses supported by implants.13-16 Two models were subjected to FEA study
à DT page 12

[2] => Untitled

12 Implant Tribune
ß DT page 11

United Kingdom Edition

Fig 5

to compare between a wide implant restoration versus the two
implant restoration of lower first
molar.

Fig 6a

January 2014

general purpose CAD/CAM software “AutoDesk Inventor” version 8.0. These parts are regular,
symmetric, and its dimensions
can be simply measured with
their full details.
On the other hand, crown is
too complicated in its geometry
therefore it was not possible to
draw it in three dimensions with
sufficient accuracy. Crown was
modelled by using three-dimensional scanner, Roland MDX-15,
to produce cloud of points or triangulations to be trimmed before
using in any other application.

Material and Methods
Three different parts were modelled to simulate the studied cases; the jaw bones, implant/abutment assembly, and crown. Two
of these parts (jaw bone and implant/abutment) were drawn in
three dimensions by commercial

The second phase of difficulty
might appear for solving the engineering problem, is importing
and manipulating three parts
one scanned and two modelled
or drawn parts on a commercial FE package. Most of CAD/
CAM and graphics packages deal
with parts as shells (outer surface only). On the other hand the
stress analysis required in this
study is based on volume of different materials.3 Therefore set
of operations like cutting volumes by the imported set of surfaces in addition to adding and
subtracting volumes can ensure
obtaining three volumes representing the jaw bone, implant/
abutment assembly, and crown.2
Bone was simulated as cylinder
that consists of two parts. The
inner part represents the spongy

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bone (diameter 14mm and height
22mm) that filling the internal
space of the other part (shell of
1mm thickness) that represents
cortical bone (diameter 16mm
and height 24mm). Two implants
were modelled one of 3.7mm diameter and the other of 6.0mm.
The implants/abutment design
and geometry were taken from
Zimmer dental catalogue (Fig. 5).
Linear static analysis was performed. The solid modelling and
finite element analysis were performed on a personal computer
Intel Pentium IV, processor 2.8
GHz, 1.0 GB RAM. The meshing
software was ANSYS version 9.0
and the used element in meshing
all three dimensional model is
eight nodes Brick element (SOLID45), which has three degrees
of freedom (translations in the
global directions). Listing of the
used materials in this analysis is
found in Table 1. The two models

[3] => Untitled

United Kingdom Edition

January 2014

were subjected to 120 N vertical
load equally distributed (20 N on
six points simulate the occlusion;
one on each cusp and one in the
central fossa). On the other hand,
the base of the cortical bone cylinder was fixed in all directions
as a boundary condition.17-21
Results and Discussion
Results of FEA showed a lot of details about stresses and deformations in all parts of the two models
under the scope of this study. Figures 6a & b showed a graphical
comparison between the crowns
of the two models which are
safe under this range of stresses
(porcelain coating, gold crown,
and implants showed the same
ranges of safety). No critical difference can be noticed on these
parts of the system. All differences might be found are due to differences in supporting points and
each part volume to absorb load
energy (equation 2).**

Table 1

the best to compressive and the
least to shear stresses22, so considering the difference in com-

à DT page 14

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The bone is known to respond

This study showed various results between cortical and spongy
bone. It was expected that the
maximum stresses in the cortical
bone was placed in the weak area
between the two implants. In addition to be higher than the case
of using one wide implant. Although the middle part of spongy
bone was stressed to the same
level in the two cases, using two
implants resulted in more volume of the spongy bone absorbed

bone. Contrarily, Figures 8a &
b, showed better performance
with cortical bone in case of using one wide implant over using
two implants, that, deformations
in cortical bone are less by 20 per
cent while the stresses are less by
about 40 per cent. The stresses
and displacements were significantly higher in the two implant
model due to having two close
holes, which results in weak area
in-between.

Only

Generally a crown placed
on two implants is weaker than
the same crown placed on one
implant. This fact is directly reflected on porcelain coating and
the two implants that have more
deflections. Comparing wide
implant model with the two implants from the geometrical point
of view it is simply noted that
cross sectional area was reduced
by 43.3 per cent while the side
area increased by 6.5 per cent.
Using one implant results as a
reference in a detailed comparison between the two models by
using equation (1) resulted in Table 2 for porcelain coating, gold
crown, implant(s), spongy and
cortical bones respectively.

Spongy bone deformation and
stresses (Table 2) seems to be the
same in the two cases. Simple and
fast conclusion can be taken that
using one wide implant is equivalent to using two conventional
implants. On the other hand a
very important conclusion can
be exerted that, under axial loading, about 10 per cent increase in
implant side area can overcome
reduction of implant cross section area by 50 per cent. In other
words, effectiveness of increasing
implant side area might be five
times higher than the increasing
of implant cross section area on
spongy bone stress level under
axial loading. Starting from Figures 7 a & b, slight differences
can be noticed on spongy bone
between the two models results.
The stresses on the spongy bone
are less by about five per cent in
the two implants model than the
one wide diameter implant.
The exceptions are the relatively increase in maximum compressive stresses and deformations of order 12 per cent and 0.3
per cent respectively.

pressive stresses less significant,
the two implants were found to
have a better effect on spongy

Implant Tribune 13

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[4] => Untitled

14 Implant Tribune

United Kingdom Edition

January 2014

ß DT page 13

the load energy** which led to
reduction of stress concentration
and rate of stress deterioration by
moving away from implants. That
is considered better distribution
of stresses from the mechanics
point of view, which may result in
longer lifetime. Porcelain coating
showed less stress in case of two
implants, longer life for the brittle
coating material is expected.
Contrarily more stresses were
found on the gold crown placed
on two implants due to its volume
reduction (less material under
the same load). This is clearly
seen in increasing stresses on
the two implants, that more load
effect was transferred through
the weak crown to the two implants. That showed maximum
stresses in the area under the
crown, while the wide implant
showed maximum stresses at its
tip. Looking to energy** absorption and stress concentration on
whole system starting from coating to cortical and spongy bone,
although the stress levels found
was too low and far from cracking danger, the following conclusions can be pointed out; the total
results favour the two implants
in spongy bone and the wide implant in the cortical layer, but the
alveolar bone consists of spongy
bone surrounded by a layer of
cortical bone. It’s also well known
that according to the degree of
bone density the alveolar bone is
classified to D1,2,3,4 23 in a descending order.
So, provided that the edentulous space after the molar extraction permits, it’s recommended in
the harder bone quality (D1,2) to
use one wide diameter implant
and in the softer bone (D3,4)
quality two average sized implants. Therefore more detailed
study to compromise between
the two implants size/design and
intermediate space can put this
stress values in safe, acceptable,
and controllable region under
higher levels of loading.

Fig 6b

Fig 7a

Fig 7b

Fig 8a

Fig 8b

Fig 9
equivalent stresses in addition
to the vertical deformity and the
total deformities were considered in the comparison between
the two models. The results were
obtained as percentages using
the wide implant as a reference.
The spongy bone showed about
five per cent less stresses in the
two implants model than the
one wide diameter implant. The
exceptions are the relatively increase in maximum compressive
stresses and deformations of order 12 per cent and 0.3 per cent
respectively.

Fig 10

**The area under the __-__
curve up to a given value of strain
is the total mechanical energy
per unit volume consumedTable 1
by the material in straining it
to that value (Fig. 9). This is easily
shown as follows in equation 2:
Summary
Restoration of single molar using
implants encounters many problems; mesio-distal cantilever due
to very wide occlusal table is the
most prominent. An increased
occlusal force posteriorly worsens the problem and increases
failures. To overcome the overload, the use of wide diameter
implants or two regular sized implants were suggested. The aim
of this study was to verify the best
solution that has the best effect
on alveolar bone under distributed vertical loading. Therefore,
a virtual experiment using Finite
Element Analysis was done us-

Table 2

ing ANSYS version 9. A simplified
simulation of spongy and cortical
bones of the jaw as two co-axial
cylinders was utilised. Full detailed with high accuracy simulation for implant, crown, and
coating was implemented. The
comparison included different

types of stresses and deformations of both wide implant and
two regular implants under the
same boundary conditions and
load application.
The three main stresses compressive, tensile, shear and the

The stresses and displacements on the cortical bone are
higher in the two implant model
due to having two close holes,
which results in weak area in-between. The spongy bone response
to the two implants was found to
be better considering the stress
distribution (energy absorbed by
spongy bone**). Therefore, it was
concluded that, using the wide
diameter implant or two average
ones as a solution depends on
the case primarily. Provided that

the available bone width is sufficient mesio distally and buccolingualy, the choice will depend
on the type of bone. The harder
D1,2 types having harder bone
quality and thicker cortical plates
are more convenient to the wide
implant choice. The D3,4 types
consist of more spongy and less
cortical bone, are more suitable
to the two implant solution. DT
Editorial note: A complete list
of references is available from the
author.

About the author
Prof. Amr Abdel Azim
Professor, Faculty of Dentistry, Cairo
University
drazim@link.net
Dr Amani M. Zaki
GBOI. 2009, Egypt
amani.m.zaki@gmail.com
Dr Mohamed I. El-Anwar
Researcher, Mechanical Engineering
Department,
National Research Center, Egypt
anwar_eg@yahoo.com

[5] => Untitled

United Kingdom Edition

January 2014

Implant Tribune 15

Time proven clinical success of
the SHORT™ implant
Prof Dr Mauro Marincola, MDS Angelo Paolo Perpetuini, Dr Stefano Carelli,
Prof G. Lombardo & Dr Vincent Morgan

I

n 1892, Julius Wolff, a
German surgeon, published his seminal observation that bone changes its
external shape and internal,
cancellous architecture in response to stresses acting on it
(Wolff’s law of bone modelling and remodelling). Therefore, it is a significant engineering challenge to design a
short implant that biocompatibly transfers occlusal forces
from its prosthetic restoration to the surrounding bone.
It requires the understanding
and application of many basic
biological, mechanical, and
metallurgical principles. It
is paramount that the entire
design of a SHORT™ implant
optimises the effectiveness
of each of its features within
the implant’s available surface area and length. Clinical success cannot be met
by any single implant design
feature such as surface area,
but rather requires the appropriate integration of all of its
features.
Since an implant’s design
dictates its clinical and mechanical capabilities, it is
scientifically approved that
bone healing around a plateau-designed implant is dif-

clinical capabilities different
from the slower forming (1–3
microns per day) of apposi-

fer of compressive forces to
the bone throughout the entire implant.3,4

Description
We analysed the most timeà DT page 16

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‘Therefore, it is a
significant engineering challenge
to design a short
implant that biocompatibly transfers occlusal forces
from its prosthetic
restoration to the
surrounding bone’

ferent than the appositional
bone (the bone that is formed
by osteoblasts after cell mediated interfacial remodelling)
around threaded implants.
The plateaued, tapered and
root-formed implant body
provides for 30 per cent more
surface area than comparably-sized threaded implants.
But more importantly, the
plateaus provide for an intramembranous-like and faster
bone formation (20–50 microns per day), resulting in a
unique Haversian bone with

tional bone around threaded
implants.1,2 Additionally, the
plateaus provide for the trans-

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[6] => Untitled

16 Implant Tribune
ß DT page 15

Fig 1

United Kingdom Edition

January 2014

Fig 16

Fig 2

proven short implant on the
market that was called the
Driskol Precision Implant in
the early 1980s, than Stryker
and the Bicon Dental Implant
from 1993 (Boston, USA).
The Bicon implant has a
bacterially-sealed 1.5o locking
taper (galling or cold welding) connection5,6 between the
abutment and implant, with
the ability for 360o of universal
abutment positioning. Having
a bacterially-sealed connection eliminates the bacterial
flux associated with clinical
odours and tastes and reduces
inflammation and bone loss
consistently.
Another unique characteristic is the sloping shoulder
that facilitates the appropriate
transfer of occlusal loads to the
bone when positioned below
the bony crest. But more practically, the sloping shoulder facilitates aesthetic implant restorations, for it provides space
for the interdental papillae with
bony support even when an
implant is contiguous to another implant or tooth. The sloping shoulder design has been,
since 1985, the basis of a sensible biological width and the
origin of platform switching.
The 360o of universal abutment positioning provides for
the extra-oral cementation of

Fig 17

Fig 3

Fig 4

Fig 5

Fig 6

Clinical long-term results
In the following long-term
case description we can observe the stability of the crestal bone around the sloping
shoulder of the plateau implant. Clinically, the soft tissue
contour around the Integrated
Abutment Crowns indicates a
healthy and stable epithelial
tissue.
The single-tooth implant is

Fig 7

Fig 19

Fig 20

Fig 8

‘The single-tooth
implant is a viable
alternative for
single tooth
replacement’

crowns; the use of the cementless and screwless Integrated
Abutment Crown (IAC™)7,
the intraoral bonding of fixed
bridges, which eliminates the
need for cutting, indexing and
soldering of bridge frameworks, multiple and easy removal of abutments over time;
and the slight aesthetic rotational adjustments during and
prior to the seating of a restoration.

Fig 18

Fig 9
Fig 10

Fig 11

Fig 14

Fig 12

Fig 13

Fig 15

a viable alternative for single
tooth replacement.8 Singletooth replacement with endosseous implants has shown satisfactory clinical performance
in different jaw locations.
Minimal or no crestal bone
resorption is considered to be
an indicator of the long-term
success of implant restorations. Mean crestal bone loss
ranging from 0.12-0.20mm has
been reported one year after
the insertion of single-tooth
implant restorations.9 After
the first year, an additional
0.01mm to 0.11mm of annual
crestal bone loss has been reported on single-tooth implant
restorations. Some implants
demonstrate no crestal bone
loss and/or crestal bone gain
after insertion of definitive
restorations.10
Crestal bone gain has been
documented on immediate and
early loaded implants with a
chemically modified surface
after one year of follow up.11
A six-year prospective study
reported that 43.8 per cent of
splinted Morse taper implants
experienced some bone gain.12
Crestal bone gain has been
documented around immediately loaded Bicon implants.13
The factors that lead to periimplant bone gain in different

[7] => Untitled

United Kingdom Edition

implant designs have not been
investigated. It would be beneficial for the dental practitioner to
understand what factors are associated with crestal bone gain
on single-tooth implants after
crown insertion. Radiographic
long-term control also as a clinical observation of the soft tissue
structures surrounding the abutment emergence profile can provide the clinician with a better
understanding of an implant’s
bone/soft tissue stability (Figs
1–12).
The ideal scenario in modern implant dentistry would be
the implant replacement for
every missing single tooth (Figs
13&14). The single tooth replacement guarantees good aesthetics, consequently to the fact
that a single crown that follows
all criteria of a natural-looking
soft tissue emergence profile
can support the soft tissue in order to recreate papillae anatomy.
Another important aspect
of single crown restorations on
implants is that the patient can
follow a better oral hygiene
compared to bridgeworks. Nevertheless, bridgeworks are commonly used as alternatives to
single tooth replacement. The

Implant Tribune 17

January 2014

Figs
Figs. 1–12_Radiographic long-term control helps maintain the implant’s bone/
soft tissue stability.
Figs. 13–16_Bridge works.
Figs. 17 & 18_Complex bridge works.
Figs. 19–22_Fixed-on-SHORTTM technique for fixed, metal free prosthetics.

Fig 22

Fig 21

About the author
depends strictly on the implant
design, which dictates the implant’s function. DT

short implants in all clinical situations. The proper selection of
an ultra-short or short implant

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

Prof. Dr Mauro Marincola
Via dei Gracchi, 285
I-00192 Roma, Italy
mmarincola@gmail.com

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‘The ideal scenario
in modern implant
dentistry would be
the implant replacement for every missing single to’

reasons are multifactorial, with
the cost benefit factor at first
place (Figs 15&16). Another
significant facet is the atrophic
bone situation of the patient,
were complicated and expensive bone graft procedures are
needed before even thinking of
placing single implants.
Alternatively to sophisticated and expensive bridge works
(Figs 17&18), cost-effective and
simple prosthetic techniques
were developed in the last years.
One of these techniques, the
Fixed on SHORT™, allows to
provide the patients with bone
atrophies or partial bone deficiencies with a fixed, metal free
prosthetic that can be supported
by four to six short implants
(Figs 19–22).
Conclusion
In this short and synthetic article,
the authors like to show the variety of treatment options when
implants and prosthetic materials are used with the criteria of
long-term crestal bone preservation, recreation and long-term
stabilisation of the biological
width around the implant/crown
and the use of short- and ultra-

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Watch the Tetric EvoCeram Bulk Fill & Bluephase Style animation at:
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[8] => Untitled

18 Implant Tribune

United Kingdom Edition

January 2014

Stem cells in implant dentistry
Dr André Antonio Pelegrine

Fig. 1 A stem cell following either self-replication or a Fig. 2 Different tissues originated from mesenchymal stem
differentiation pathway.
cells.

Fig. 4b The needle inside the bone marrow.

Fig. 5a A bone graft being harvested from the
chin (mentum).

Fig. 3 The diversity of cell types present in the bone
marrow.

Fig. 4a Point of needle puncture for access to the bone
marrow space in the iliac bone.

Fig. 5c A bone graft being harvested Fig. 5d_A bone graft being harvested from
Fig. 5b A bone graft being harvested
from the angle of the mandible (ramus). from the angle of the skull (calvaria). the angle of the leg (tibia or fibula).

Fig. 5e_A bone graft from the pelvic bone
(iliac).

Fig. 6 A critical bony defect created in the Fig. 7 A primary culture of adult mesenskull (calvaria) of a rabbit.
chymal stem cells from the bone marrow
after 21 days of culture.

Fig. 8a A CT image of a rabbit’s skull after bone-sparing
grafting without stem cells
(blue arrow). Note that the
bony defect remains.

Fig. 10a A histological image of the site grafted
with bank bone combined with bone marrow.
Note the presence of considerable amounts of
mineralised tissue.

Fig. 10b A histological image of the site
grafted with bank bone not combined with
bone marrow. Note the presence of low
amounts of mineralised tissue.

Fig. 11b_Bone marrow transfer into a
conic tube in a sterile environment (laminar flow).

he human body contains
over 200 different types
of cells, which are organised into tissues and organs
that perform all the tasks required to maintain the viability
of the system, including reproduction. In healthy adult tissues, the cell population size is
the result of a fine balance between cell proliferation, differentiation, and death. Following
tissue injury, cell proliferation
begins to repair the damage. In
order to achieve this, quiescent
cells (dormant cells) in the tissue become proliferative, or
stem cells are activated and differentiate into the appropriate
cell type needed to repair the
damaged tissue. Research into
stem cells seeks to understand
tissue maintenance and repair
in adulthood and the derivation
of the significant number of cell
types from human embryos.
It has long been observed
that tissues can differentiate

into a wide variety of cells, and
in the case of blood, skin and
the gastric lining the differentiated cells possess a short halflife and are incapable of renew-

Fig. 11a_Bone marrow.

Not only can stem cells be
isolated from both adult and
embryo tissues; they can also
be kept in cultures as undifferentiated cells. Embryo stem

‘Research into stem cells seeks to understand tissue maintenance and repair
in adulthood and the derivation of the
significant number of cell types from
human embryos’
ing themselves. This has led to
the idea that some tissues may
be maintained by stem cells,
which are defined as cells with
enormous renewal capacity
(self-replication) and the ability
to generate daughter cells with
the capacity of differentiation.
Such cells, also known as adult
stem cells, will only produce
the appropriate cell lines for
the tissues in which they reside
(Fig 1).

cells have the ability to produce
all the differentiated cells of
an adult. Their potential can
therefore be extended beyond
the conventional mesodermal
lineage to include differentiation into liver, kidney, muscle,
skin, cardiac, and nerve cells
(Fig 2).
The recognition of stem cell
potential unearthed a new age
in medicine: the age of regenerative medicine. It has made it

Fig. 8b A CT image of a rabbit’s skull after bone-sparing
grafting with stem cells.
Note that the bony defect
has almost been resolved.

possible to consider the regeneration of damaged tissue or
an organ that would otherwise
be lost. Because the use of
embryo stem cells raises ethical issues for obvious reasons,
most scientific studies focus on
the applications of adult stem
cells. Adult stem cells are not
considered as versatile as embryo stem cells because they
are widely regarded as multipotent, that is, capable of giving
rise to certain types of specific
cells/tissues only, whereas the
embryo stem cells can differentiate into any types of cells/
tissues. Advances in scientific
research have determined that
some tissues have greater difficulty regenerating, such as the
nervous tissue, whereas bone
and blood, for instance, are
considered more suitable for
stem cell therapy.
In dentistry, pulp from primary teeth has been thoroughly investigated as a potential

Fig. 9 A bone block from a musculoskeletal tissue bank.

Fig. 11c_Bone marrow homogenisation in a
buffer solution (laminar flow).

source of stem cells with promising results. However, the regeneration of an entire tooth,
known as third dentition, is a
highly complex process, which
despite some promising results with animals remains very
far from clinical applicability.
The opposite has been observed
in the area of jawbone regeneration, where there is a higher level of scientific evidence
for its clinical applications.
Currently, adult stem cells
have been harvested from bone
marrow and fat, among other
tissues.
Bone marrow is haematopoietic, that is, capable of producing all the blood cells. Since
the 1950s, when Nobel Prize
winner Dr E Donnall Thomas
demonstrated the viability of
bone marrow transplants in
patients with leukaemia, many
lives have been saved using
this approach for a variety of
immunological and haemat-

[9] => Untitled

United Kingdom Edition

Fig. 11d_Bone marrow combined with Ficoll (to aid cell separation).

opoietic illnesses. However, the
bone marrow contains more
than just haematopoietic stem
cells (which give rise to red
and white blood cells, as well
as platelets, for example); it
is also home to mesenchymal
stem cells (which will become
bone, muscle and fat tissues,
for instance; Fig 3).
Bone marrow harvesting is
carried out under local anaesthesia using an aspiration needle through the iliac (pelvic)
bone. Other than requiring a
competent doctor to perform
such a task, it is not regarded as
an excessively invasive or com-

‘Bone reconstruction is a challenge
in dentistry (also in
orthopaedics and
oncology) because
rebuilding bony
defects caused by
trauma, infections,
tumours or dental
extractions requires
bone grafting’
plex procedure. It is also not
associated with high levels of
discomfort either intra or postoperatively (Figs 4a&b).
Bone reconstruction is a
challenge in dentistry (also in
orthopaedics and oncology) because rebuilding bony defects
caused by trauma, infections,
tumours or dental extractions
requires bone grafting. The
lack of bone in the jaws may
impede the placement of dental
implants, thus adversely affecting patients’ quality of life. In
order to remedy bone scarcity,
a bone graft is conventionally
harvested from the chin region
or the angle of the mandible.
If the amount required is too
large, bone from the skull, legs
or pelvis may be used. Unlike
the process for harvesting bone
marrow, the process involved
in obtaining larger bone grafts
is often associated with high
levels of discomfort and, occasionally, inevitable post-operative sequelae (Figs 5a-e).
The problems related to
bone grafting have encour-

January 2014

Fig. 11d_Bone marrow combined with Ficoll (to aid cell separation).

Implant Tribune 19
aged the use of bone substitutes
(synthetic materials and bone
from human or bovine donors,
for example). However, such
materials show inferior results
compared with autologous
bone grafts (from the patient
him/herself), since they lack
autologous proteins. Therefore, in critical bony defects,
that is, those requiring specific
therapy to recover their original contour, a novel concept to
avoid autologous grafting, involving the use of bone-sparing

material combined with stem
cells from the same patient,
has been gaining ground as a
more modern philosophy of
treatment. Consequently, to the
detriment of traditional bone
grafting (with all its inherent
problems), this novel method of
combining stem cells with mineralised materials uses a viable
graft with cells from the patient
him/herself without the need
for surgical bone harvesting.
à DT page 20

[10] => Untitled

20 Implant Tribune

United Kingdom Edition

ß DT page 19

•
•

Until recently, no studies had compared the different methods available for using bone marrow stem cells
for bone reconstruction. In the
following paragraphs, I shall
summarise a study conducted
by our research team, which
entailed the creation of critical bony defects in rabbits and
subsequently applying each of
the four main stem cell meth-

Fig. 11h_A bovine bone graft combined
with a bone marrow stem cell concentrate.

Fig. 11f_Second centrifuge spin.

•
ods used globally in order to
compare their effectiveness in
terms of bone healing:1

Fig. 11g_The pellet containing the bone
marrow mononuclear cells after the second
centrifuge spin.

•

fresh
bone
marrow
(without any kind of
processing)
a bone marrow stem
cell concentrate

January 2014

a bone marrow stem
cell culture
a fat stem cell culture
(Figs 6&7).

In a fifth group of animals,
no cell therapy method (control group) was used. The best
bone regeneration results were
found in the groups in which a
bone marrow stem cell concentrate and a bone marrow stem
cell culture were used, and the
control group showed the worst
results. Consequently, it was
suggested that stem cells from
bone marrow would be more
suitable than those from fat
tissue for bone reconstruction
and that a simple stem cell concentrate method (which takes a
few hours) would achieve similar results to those obtained using complex cell culture procedures (which take on average
three to four weeks; Figs 8a&b).
Similar studies performed
in humans have corroborated
the finding that bone marrow
stem cells improve the repair of
bony defects caused by trauma,
dental extractions or tumours.
The histological images below
illustrate the potential of bonesparing materials combined
with stem cells for bone reconstruction (Fig 9). It is clear that
the level of mineralised tissue
is significantly higher in those
areas where stem cells were
applied (Figs 10a&b).

Constic:
Do more with less.

Evidently, although bone
marrow stem cell techniques
for bone reconstruction are
very close to routine clinical
use, much caution must be exercised before indicating such a
procedure. This procedure requires an appropriately trained
surgical and laboratory team,
as well as the availability of the
necessary resources (Figs 11a–
h, taken during laboratory manipulation of marrow stem cells
at São Leopoldo Mandic dental
school in Brazil). DT

NEW !

All images courtesy of Células Tronco em Implantodontia.2

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References
1 André Antonio Pelegrine, Antonio
Carlos Aloise, Allan Zimmermann et al.,
Repair of critical-size bone defects using
bone marrow stromal cells: A histomorphometric study in rabbit calvaria. Part
I: Use of fresh bone marrow or bone marrow mononuclear fraction, Clinical Oral
Implants Research, 00 (2013): 1–6.
2 André Antonio Pelegrine, Antonio
Carlos Aloise & Carlos Eduardo Sorgi da
Costa, Células Tronco em Implantodontia
(São Paulo: Napoleão, 2013).

thereby benefit from increased safety during
application. Whether for small Class I restorations,
linings or fissure sealing: start relying on Constic
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About the author
Dr André Antonio Pelegrine is a specialist dental surgeon in periodontology and implant dentistry (CFO) with
an MSc in Implant Dentistry (UNISA),
and a PhD in clinical medicine (University of Campinas). He completed
postdoctoral research in transplant
surgery (Federal University of São
Paulo). He is an associate lecturer
in implant dentistry at São Leopoldo
Mandic dental school and coordinator of the perio-prosthodontic-implant
dentistry team at the University of
Campinas in Brazil. He can be contacted at pelegrineandre@gmail.com.
AZM_Constic_GB_E_2013_8.indd 1

16.08.13 12:50

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[cover] => Implant Tribune UK No. 1, 2014

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Single molar restoration — Wide implant versus two conventional / Time proven clinical success of the SHORT™ implant / Stem cells in implant dentistry

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