Focus on implants - Nobel Biocare

98
Bilateral sinus graft surgery with Piezo surgery
Maxillary sinus grafting is an
established procedure for the
sole purpose of creating bone
in the severely resorbed
posterior maxilla without
which endosseous dental
implant therapy would be
precluded. The introduction
of this procedure by Tatum
using the lateral approach in
1976 1 and published
subsequently in 1980 by
Boyne 2 has allowed the
placement of innumerable
dental implants in patients
who otherwise would not
have been able to benefit
from dental implant based
therapy.
In this procedure a large
buccal flap is raised and the
lateral wall of the sinus is
used to access the maxillary
sinus, allowing the gentle
lifting and displacement of
the Schneiderian membrane
medially and superiorly to
allow packing of the preferred
Figure 1: Pre-op, right side
<strong>Focus</strong> on implants
graft material. It seems the
high vascularity 3, 4 of the sinus
allows the use of most
types material successfully,
allograft, zenograft, alloplast
or autograft all seem to
reliably form de novo bone
5, 6,
7, 8 for either concomitant
implant placement in as little
as 1-2mm of native cortical
bone 9, 10 or for later implant
placement.
Sinus grafting is a
predictable and safe
procedure with few complications,
the most common
being tearing of the fragile
thin (0.8mm) membrane in
up to 40% or so of cases 11
and intra-operative bleeding
from intra-osseous vessels
traversing the lateral bone
wall of the sinus 12 .
The arterial blood vessels
when present are only clearly
visible in around 50% of
cases on CT scans and they
may be encountered during
By Dr Nikhil D Sisodia BDS & Dr Konstantin Varga DMD
sinus window preparation in
12, 13, 14
up to 20% of cases.
Intra-operative bleeding from
these vessels may be self
limiting, controlled by
cauterisation or using bone
wax. 14
Smaller tears of the
membrane usually do not
require repair or the use of a
barrier membrane to allow
sinus grafting to continue as
the membrane tends to fold
back onto itself. Larger tears
can either repaired with a
resorbable barrier membrane
or if too large to contain the
graft material may result in
the abandonment of the
procedure, leaving threeto-six
months for the
membrane to repair itself
before re-visiting the site to
complete the procedure.
Tears in the membrane in
themselves do not seem to
have an adverse effect on the
outcome of the implant
therapy and ultimately
11, 15, 16, 17
implant survival.
The conventional
approach in sinus grafting is
to use a round surgical
diamond bur in a straight
hand piece to make the
lateral window in the
bone allowing subsequent
infracture of this window to
make a trapdoor allowing
careful reflection and
elevation of the Schneiderian
membrane. The bur itself is
capable of cutting through
any underlying vessel or the
sinus membrane; so it is no
surprise that these are the two
most common complications.
One possible way of
obviating these problems
described above is the use of
Piezo-surgical units, an
option that reduces the
chances of the instrument
itself causing either of the two
problems described as Piezo
surgery units do not affect
soft tissues. A growing
number of surgeons are
adopting the use of Piezon
units for surgery such as
intra-oral grafting where
accurate isometric cuts are
possible, sinus grafting where
the lateral window is
prepared with the Piezon
unit, relatively atraumatic
tooth extraction is possible
with the luxation
insert, nerve lateralisation
procedures made simpler,
osteotomy preparation is
possible with appropriate tips
and the list is ever
expanding.
18, 19, 20
The case study shown in
this article highlights the soft
tissue safety of this modern
approach using Piezo-surgical
technology where bilateral
sinus grafting was planned
with concomitant implant
placement.
Both upper second
pre-molars were to be
Figure 5: CT assessment, right side Figure 6: CT assessment, left side Figure 7: Flap, right side
Figure 8: Flap, left side
7 March 2008
replaced with implants and
additional bone volume was
required in order to place
implants of the desired
length. The pre-operative
situation is seen in Figures
1-6 where a narrow and tight
space for implant and sinus
surgery is observed due to the
loss of mesio-distal space
from tooth migration and also
loss of buccal bone volume.
With the flaps raised,
lateral windows were
prepared with the use of a
Piezo surgery unit (Mectron,
Genoa, Italy) and it was
during this window
preparation that intra-osseous
blood vessels were
encountered on both sides,
Figures 7-12.
These vessels were
carefully dissected off the
membrane (Figures 13 & 14),
allowing the successful
elevation and reflection of the
sinus membrane seen in
Figure 9: Blood vessel, right side Figure 10: Blood vessel, left side Figure 11: Window preparation, right side Figure 12: Window preparation with Piezo
surgery, left side
Figure 13: Dissected vessel off membrane,
right side
Figure 2: Pre-op, left side
Figure 14: Dissected vessel off membrane, left
side
Figure 3: Pre-op, panoramic Figure 4: Panoramic image negative
Figure 15: Special elephant foot insert to
reflect sinus membrane
Figure 16: Prepared sinus, right side

7 March 2008 <strong>Focus</strong> on implants 99
Figure 17: Prepared sinus,
left side
Figures 15, 16 & 17.
Once the membrane had
been elevated, osteotomies
were prepared for the
simultaneous placement of
two implants (SPI implant,
Alpha Bio, Israel, modified
and marketed as NobelActive
by NobelBiocare), Figures
18 & 19.
With the osteotomies
prepared, the sinuses were
both packed with large
particulate Bio-Oss (Geistlich
Biomaterials, Wolhusen,
Switzerland), Figures 20 &
21. The two implants were
then placed by hand with
excellent primary stability
and closed over with cover
screws, Figures 22- 25.
The lateral windows were
covered with a bovine
peri-cardium membrane
(Tutogen Medical GmbH,
Germany) and the flaps
sutured with tension free
closure, Figures 26-29.
The post-operative periapical
radiographs, Figures
30 & 31, show a good
position and volume of tissue
around the implants for later
restoration once integrated.
Although experienced
surgeons will not have any
problems handling these
frequently encountered
problems, even less experienced,
but properly trained
surgeons should be able to
perform these and other
surgical procedures with a
greater degree of safety. 19
The advantage of Piezo
surgery is that it creates a
virtually blood free operating
area increasing visibility and
minimal heat is generated by
the inserts, minimising
necrosis due to cellular
damage. One slight drawback
may be that it is slower than
conventional approaches, but
the advantages far outweigh
this slight inconvenience.
References
Figure 18: Implant osteotomy, right side Figure 19: Implant
osteotomy, left side
Figure 21: Graft placement, left side Figure 22: Alpha bio SPI implant placement, Figure 23: Alpha bio SPI implant
placement, left side
Figure 25: Stable implant and graft in situ,
left side
1. Tatum H. Maxillary and
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6
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Figure 26: Bovine pericardium membrane,
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Figure 27: Bovine pericardium membrane,
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Figure 29: Flap closure, left side Figure 30: Post-op radiograph, right side Figure 31: Post-op radiograph, left side
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Figure 20: Graft placement, right side
Figure 24: Stable implant and graft in situ, right
Figure 28: Flap closure, right side
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Dr Nikhil Sisodia BDS qualified from
Bristol University in 1995. Following
a year as a Senior House Officer in
Restorative Dentistry and several years
in general practice in London, he
found his passions were in the
cosmetic and advanced restorative
field, which led him to undertake
further courses in the UK and abroad.
He is an active member of the
American Academy of Cosmetic
Dentistry, Association of Dental
Implantology, a Fellow of the International Congress of Oral
Implantology and is currently Country Chairman (UK) for the
European Society of Cosmetic Dentistry. Nik is also an active
member of the British Academy of Cosmetic Dentistry and
serves on the Board of Directors as Chairman of the Congress
Committee. Dr Konstantin Varga DMD, Master of Oral
Medicine in Implantology, practises in private practice in
Torquay, Devon..