This document discusses keys to success for dental implant placement in the posterior maxilla. The posterior maxilla presents several challenges for implants due to poor bone quality and limited bone height from sinus pneumatization. A case report describes using the crestal approach for sinus elevation and placing an implant bicortically stabilized between the crest and sinus floor. This provides high initial stability and allows placement of longer implants. The author found this technique resulted in higher success rates compared to conventional protocols. Bicortical stabilization of implants is an effective approach but requires expertise to avoid membrane perforation.

1. Dental Practice // March-April 2013 // Vol 11 No 500
Keys to success for implant
placement in posterior maxilla
implantology section
INTRODUCTION
Dental implant therapy into the posterior
maxilla has always been and continues to be a
challenge due to various limitations in this
region such as poor bone density, sinus
pneumatization, lateral and vertical bone
resorption, high occlusal forces and area of
limited access. Further, if the implant is
placed into poor density posterior maxilla,
the bone which forms around the osseointe-
grated implants does not show very high
bone to implant surface contact (BIC) per-
centage, thus in several cases the implant even
after successful osseointegration may fail
once it is restored in function.
In past, several modifications to the con-
ventional implant therapy have been done to
make the implant successful into the posteri-
or maxilla. Achieving the adequate initial sta-
bility and bone implant contact are two
major challenges into the posterior maxilla.
Various protocols such as lateral bone aug-
mentation using osteotomes, use of wide and
long implant with deeper threads and high
pitch value, use of implant with specific sur-
face (HA coated implant), submerging
implant platform apical to the ridge crest,
bicortical stabilization of implant, and pro-
gressive loading of implant have been applied
to make the implant successful into the pos-
terior maxilla.
Besides the compromised bone density,
sinus pneumatization is the great challenge in
the posterior maxilla which results in limited
bone height availability under the sinus. In
such cases, maxillary sinus lifting and grafting
has been providing promising results. The
sinus-lift procedure was first performed by
Dr. Hilt Tatum Jr. in 1974 during his period
of preparation to begin sinus grafting. The
first sinus graft was performed by Tatum in
February, 1975 in Lee County Hospital in
Opelika, Alabama. This was followed by the
placement and successful restoration of two
Endosteal implants. After this, suitable
instruments were developed to manage the
lining elevation from the different anatomical
surfaces encountered in sinuses. Tatum first
presented the concept at The Alabama
Implant Congress in Birmingham, Alabama
in 1976 and presented the evolution of tech-
nique during multiple podium presentations
each year until 1986 when he published an
article describing the procedure. Dr. Philip
Boyne was introduced to the procedure when
he was invited, by Tatum, to be "The
Discusser" of a presentation on sinus grafting
given by Tatum at the annual meeting of The
American Academy of Implant Dentistry in
1977. Boyne and James authored the first
publication on the technique in 1980 when
they published case reports of autogenous
grafts placed into the sinus and allowed to
heal for 6 months, which was followed by the
placement of blade implants.
FIG 3 & 6: Dental implant with sharp and self tapping threads at the apical third and self condensing body can be
placed after minimal drilling and achieves high initial stability even into poor density bone.
FIG 7 & 8: Set of osteotomes which are used for lateral
bone condensation and sub-crestal sinus elevation.
FIG 1 & 2: After the osteotomy preparation for the implant 2mm short of sinus floor, the rest of the sinus floor is
either grinded up using diamond tips/burs or fractured up using osteotome and the implant is placed by stabilis-
ing its apex into the sinus floor and collar into the crest (Bicortical stabilization)
DR. AJAY VIKRAM SINGH AND DR. SUNITA SINGH

2. Dental Practice // March-April 2013 // Vol 11 No 5 00
LIMITATIONS WITH POSTERIOR MAXILLA
1. Poor bone quality (type IV/ D4) - challenge
to achieve adequate initial stability of the
implant
2. Limited bone height due to sinus pneuma-
tisation and vertical bone resorption of
ridge crest
3. Reduced bone width because of lateral
resorption of posterior maxilla towards the
hard palate, which also results in final pros-
thesis with facial cantilevering
4. Area of less visibility and access
5. Proximity with sinus floor, posterior supe-
rior artery etc.
KEYS TO SUCCESSFUL IMPLANT THERAPY IN
POSTERIOR MAXILLA
1. Longest and widest possible implant
should be placed
2. Bicortical implant stabilization – implant
platform is stabilized into high density
crestal bone and its apex into high density
sinus floor to achieve adequate initial
implant stability. (Figures 1 & 2)
3. Using more number of implants for mul-
tiple unit prosthesis
4. The implant with sharp self tapping deep-
er threads should be preferred to achieve
high primary stability in poor density tra-
becular bone (Figures 3 - 6).
5. Implants with faster osseointegrating sur-
faces like Hydroxyapatite coated surface
implants; SLA surface implants should be
preferred.
6. Implant can be submerged 1.0 mm apical
to the ridge crest to prevent its premature
loading and micromovements during its
healing phase.
7. Lateral bone condensation using special
set of osteotomes to enhance the density of
trabecular bone around the implant
(Figures 7 & 8).
8. Longer submerged healing period for the
implant.
9. Progressive bone loading to enhance the
density of trabecular bone around the
implant.
10. Sinus grafting to regenerate new bone
into the sinus so that longer implant can
be placed. (Figures 9 & 10).
To approach the sinus for the
Schneiderian membrane elevation and sinus
floor grafting, Tatum advocated two
approaches lateral as well as crestal. The later-
al approach is usually preferred when sub
antral bone is only 3-4 mm and a sinus mem-
brane elevation is required to be performed
to more than 4-5 mm. It should also be pre-
ferred when sinus grafting is performed for
multiple number of implants. Sub crestal
approach is less invasive and should be pre-
ferred in cases where 2-4 mm of sinus eleva-
tion is required to place an adequately long
implant and to stabilize its apex into the high
density sinus floor. The sub crestal approach
of sinus elevation was first performed by Hilt
FIG 18: Crestal bone is exposed using a soft tissue
punch.
FIG 19 & 20: Implant osteotomy is prepared in the usual fashion about 2.0 mm short of sinus floor.
FIG 13 - 17: Various CT sections are showing only 8.0 mm sub-antral bone height and poor bone density. Thus the sinus lifting with sub-crestal approach and placement of 6 x
11.5 tapered implant is planned with CT.
FIG 11 & 12: Missing maxillary molar (clinical view and radiograph)FIG 9 & 10: After the membrane has been lifted up to the desired height, sinus floor
is grafted using autogenous bone or bone substitutes and implant is inserted.

3. Dental Practice // March-April 2013 // Vol 11 No 500
implantology section
Tatum in 1974 and published by Summer in
1994.
ADVANTAGES OF THE CRESTAL APPROACH
(SUMMER’S OSTEOTOME TECHNIQUE)
1. Less invasive procedure.
2. Improves maxillary bone density, which
allows greater initial stability of implants.
3. Less amount of grafting material is
required to fill the lifted sinus membrane.
4. No barrier membrane is required
5. Limited flap elevation is required which
maintain the blood supply to the lateral
wall of the sinus.
CASE REPORT
A 48 year old female patient, medically fit for
the implant therapy, reported for the replace-
ment of missing tooth no.26. Radiographs
and dental CT revealed the availability of
only 8.0 mm bone under the maxillary sinus.
A DentaScan also showed poor bone density
at the implant site. To place an adequately
long implant with adequate initial stability, a
sinus elevation procedure with sub-crestal
approach was planned. The ridge form was
good and the marginal tissue was thick, stable
and keratinised so the implant placement
using tissue punch was planned. The osteoto-
my for the implant was prepared in the usual
fashion but 2.0mm short of the sinus floor.
Further, an adequate size osteotome was
used to fracture up the sinus floor and lift up
the sinus membrane. The PRF plug which
was prepared from the venous blood of the
patient was introduced into the osteotomy to
guard the sinus membrane against rupture.
The bone substitute (HA + β-tcp) was intro-
duced into the osteotome and pushed up
using the osteotome which further elevated
the sinus membrane to the desired height.
The implant with deeper threads
(6x11.5mm) was then placed and stabilized
into the sinus floor. Because the implant is
stabilised bicortically it achieved a primary
stability of more than 35Ncm and the
implant was left to heal with open protocol.
The implant is restored in function after 4
month of open healing. The follow-up radi-
ograph after one year showed stable crestal
bone level and new bone regeneration into
the grafted sinus.
RESULT
The author practiced conventional implant
therapy in the posterior maxilla for years
where he used hundreds of varying design
FIG 21 & 22: After the osteotomy has been prepared 2.0 mm short of sinus floor, an adequate size osteotome is
used to fracture up the sinus floor and to lift up the Schneiderian membrane.
FIG 27: The use of mechanical driver
(torque ratchet) is showing that the
implant has achieved primary sta-
bility more than 35 Ncm because it
has been stabilised bicortically
FIG 28 & 29: Implant at the final position. Gingival former is inserted for
transgingival healing of the implant
FIG 23 & 24: The PRF (platelet-rich fibrin)
is prepared from the patient’s venous
blood which was withdrawn before
surgery and centrifuged in a table top
centrifuge machine. This fibrin is first
inserted into the prepared osteotomy
and pushed using osteotome to place it
under the sinus membrane. It provides a
protection to the membrane against
rupture during its further elevation and
grafting. It also enhances the bone
regeneration potential of the graft
material.
FIG 25 & 26: The bone substitute (HA + β-Tcp) is now used to graft the elevated sinus floor and implant is inserted

4. root form implants in the posterior maxilla.
The poor bone density, availability of limited
bone height (due to sinus pneumatization)
and high force factors forced him to place the
short length implant, submerging it apical to
ridge crest, uncovering the implant after
more than 6 month submerged healing time,
following the progressive loading protocols.
This protocol required two surgical proce-
dures, long healing time and longer time span
to restore the implant. Further, the author
faced a considerable number of implant fail-
ures with the conventional protocol because
he was able to place only the short length
implant in most cases. Moreover, to avoid the
premature loading of the implant during its
healing phase he was required to submerge
implant sub crestal which often resulted in
the loss of primary stability. Since the last
couple of years, to avoid such problems and
to maximize the success rate of implant in
posterior maxilla, the Author switched over
to long implants and stabilized them bicorti-
cally. Bicortical stabilization of the implant
result in several advantages such as placement
of the implant 4-5 mm longer than usual,
high primary stability of the implant, most of
the implant are placed with non submerged
protocol, shorter healing period for the
implant (3-4 months), less implants are
required to support multiunit prosthesis and
no progressive loading is required in most
cases.
CONCLUSION
Author placed more than 200 implants in the
posterior maxilla in a period of 3 years where
he stabilized the implant bicortically with or
without sinus grafting. Most of the implants
achieved primary stability more than 35 Ncm
and hence placed with non submerged heal-
ing protocol. Most implants restored in func-
tion after the healing period of 3-4 months
without following any progressive loading
protocol.
When the author compared this newer
protocol with the conventional one, he found
more promising results and a significantly
higher success rate with the newer technique.
Stabilizing the implant apex into the high
density sinus floor resulted in a higher success
rate. The author would like to mention here
that this technique should only be performed
by clinicians who have expertise in perform-
ing sinus lifting with crestal approach to
avoid inadvertent rupture of the
Schneiderian membrane and post operative
complication. Others with less expertise in
this technique should follow protocols such
as lateral bone condensation, placing the
implant platform apical to the ridge crest,
using widest possible implant with self tap-
ping threads and self condensing body to
maximize the initial stability and to enhance
the bone implant surface contact, progressive
bone loading to strengthen the trabecular
bone around the osseointegrated implant etc.
to achieve a higher success rate of implant
placement in the posterior maxilla.
For a complete list of references, email:
info@dental-practice.biz
Dr. Ajay Vikram Singh graduated in 2003 from Saraswati
Dental College, Lucknow, and received PG. certificate
training in Implantology from India. He received
advanced level implant training at various centers and
continuing education programmes in USA. He also
received continuing education in implantology at the
School of Dentistry, The University of Queensland in
Australia. Currently, Dr. Ajay has written several articles
on implantology in various national and international
journals. Dr. Ajay has authored a dental implant book
“Clinical Implantology” published worldwide by
“Elsevier”. Dr. Ajay is the founder of International Implant
Training Centre (IITC), Agra where he trains several den-
tists from India and abroad in basic and advanced level
implantology. He runs a private practice at Dr. Ajay
Dental Clinic & Research Centre, Agra. For any query, he
About the AUTHORS
Dental Practice // March-April 2013 // Vol 11 No 5 00
FIG 31 & 32: Clinical view 4 month after implant insertion. Gingival former
is replaces with abutment.
FIG 35: Radiograph one year after restoration is showing
new bone formation into the grafted sinus and main-
tained crestal bone level around the implant collar.
FIG 33 & 34: Implant is restored in function using cement retained zirconium crown (CZAR- Monolithic, Katara Dental)
FIG 30: Post operative radiograph in
showing bicortically stabilized
implant and grafted sinus.