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The use of zygomatic implants for the rehabilitation of atrophic
maxillas with 2 different techniques: Stella and Extrasinus
Ernesto Barquero Cordero, MSD,a Cesar A. Magalhes Benfatti, PhD,b
Marco A. Bianchini, PhD,c
Leonardo Vieira Bez, MSD,d
Kyle Stanley, DDS,e
andRicardo de Souza Magini, PhD,f Santa Catarina, BrazilUNIVERSITY FEDERAL OF SANTA CATARINA
The zygomatic implant anchorage is a surgical technique that provides a new perspective for patients withsevere maxillary atrophy, increasing predictability and reduced cost of treatment, besides being a tool for the hardshipsof the rehabilitation of such a challenging region. This article describes 2 clinical cases with zygomatic implants withdifferent techniques (Stella and Extrasinus) and both with immediate loading and accompanying clinical radiographicfollow-up procedures of 12 and 24 months, respectively. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011;112:e49-e53)
The rehabilitation of patients with severely atrophiedmaxillas presents a major challenge owing to the com-
plexity of its implementation. The problem presents itself
because of the lack of height and width of the alveolar
ridge, this being a result of insufficient bone, extractions,
trauma, infection, or maxillary sinus pneumatization.1-3
Several surgical techniques have been developed to
successfully increase the volume of bone: iliac crest
graft, Le Fort I, guided bone regeneration, sinus lifting,
and combinations of these procedures.4-9 These treat-
ments also reduce patient comfort, increase morbidity,
require several surgeries, and require the use of remov-
able prostheses for a long period of time.10,11
Implants placed in grafted areas have various success
rates, with the literature suggesting a rate of 82% to 84%
with a clinical follow-up of 12 to 60 months.12
Aiming to simplify the treatment of these patients,
increasing the predictability of outcomes and decreasing
morbidity, treatment time, and avoiding bone grafts,
Brnemark and his team13 in 1988 implemented the an-choring technique known as zygomatic implants (ZI) in
some research centers.Initially this technique was designed to treat victims of
trauma, tumor resection, or congenital defects. These pa-tients present with a considerable loss of bone structure14
and few regions offering anchorage for the implants.These regions consisted of the body of the zygoma or the
frontal portion of the zygomatic bone15 presenting a greatalternative. With time, the technique has been refined,
allowing patients with severe bone resorption to be re-stored predictably to proper function and esthetics and
with a success rate similar to implants placed using theconventional technique.16
There are different techniques for fixation of zygomaticimplants. The technique developed by Brnemark17 calls
for a Le Fort I incision, allowing the displacement of alarge flap to facilitate exposure of the zygomatic bone, and
the realization of a window for the displacement of thesinus membrane. The technique of Stella and Warner18
differs from the original technique, as there is no need fora window opening on the wall of the maxillary sinus, only
1 channel orientation, and there is no concern for theintegrity of the sinus membrane. The third technique19 has
no need for a window opening or a channel in the wall ofthe maxillary sinus because of the externalization of the
zygomatic implants in relation to sinus. This article re-ports 2 clinical cases that were rehabilitated with different
fixation techniques, with a radiographic follow-up of 24and 48 months, respectively.
CASE DESCRIPTION
Case 1A 65-year-old female patient at the Center for Teaching
and Research in Dental Implants (CEPID) at the Federal
University of Santa Catarina (UFSC) presented to perform an
aPhD program in Implantology, University Federal of Santa Catarina,
Santa Catarina, Brazil.bAssociate Professor of Implantology, University Federal of Santa
Catarina, Santa Catarina, Brazil.cProfessor of the Phd and Masters Degree Program of Implantology,University Federal of Santa Catarina, Santa Catarina, Brazil.dResident of Implantology Program, University Federal of Santa
Catarina, Santa Catarina, Brazil.eResident of Implantology Program, University Federal of Santa
Catarina, Santa Catarina, Brazil.fChairman and Professor of PhD and Masters Degree Program of
Implantology, University Federal of Santa Catarina, Santa Catarina,
Brazil.
Received for publication Apr 28, 2011; accepted for publication May
15, 2011.
1079-2104/$ - see front matter
2011 Mosby, Inc. All rights reserved.
doi:10.1016/j.tripleo.2011.05.008
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implant reconstruction. Examining the panoramic radiograph
revealed bone loss around the upper and lower teeth, observed
clinically. With the impossibility of keeping these teeth, treat-ment options were introduced in the upper arch that would
use 4 implants, 2 anchored in the zygomatic bone and 2 in the
anterior region. The lower jaw had a treatment plan to place
4 implants. Both treatments had the possibility of immediate
loading.
The procedure was performed under general anesthesia
and was initiated by tooth extractions and smoothing maxil-
lary and mandibular alveolar ridges. Once the tissue was
reflected and the body of the zygoma was located, drilling
was initiated. With a round bur, a channel or slot was com-
pleted to define the orientation of the trajectory of the drills.
Then, the following sequence was used: 2.9-mm drill bit,
2.9-mm twist drill, 3.5-mm pilot drill, and 3.5-mm twist drill,always aiming the position of the platform of the implant to
lie as close as possible to the crest of the ridge. The next step
was the installation of the zygomatic implants, 4.1 diameter
52.0 mm in the posterior left ridge and 4.1 diameter 45.0 mm
in the right posterior border. Two implants measuring 4.1
13.0 mm were placed in the anterior. We used the posterior
multiunit abutments on 17 (right side) and 30 (left side),
both with a height of 4 mm, in order to have the emergence
profile located in the molar region. Because the torque was
greater than 40 Ncm for the implants in both arches, an imme-
diate loading protocol was initiated, tissue was sutured, and
acrylic resin (Duralay, Reliance) was used to secure the abut-
ment transfers in both arches and an impression for manufactur-
ing the prostheses was completed. After 48 hours, the prostheses
were installed, restoring function and esthetics for the patient.Panoramic radiographs were performed at 12 and 24 months for
the control treatment (Fig. 1, A-G).
Clinical case 2A 68-year-old male patient presented to the CEPID at
UFSC for rehabilitation of the upper jaw. On clinical exam-
ination there was a fixed prosthesis supported by implants in
the lower jaw and upper jaw with a thin ridge. It was sug-
gested that the patient have implants anchored in the zygo-
matic bone owing to the desire not to undergo a complex
reconstruction with extraoral donor sites. The procedure
started in the hospital with a LeFort type I incision, using the
ZI externalized technique. After the flap was reflected, thesequence of drilling included 2.9-mm pilot drill, 2.9-mm twist
drill, 3.5-mm pilot drill, and 3.5-mm twist drill. After the
placement of the implant platform directly over the ridge, the
installation of four zygomatic implants was completed, two
on the left side: 4.1 diameter 48 mm and 4.1 diameter 45
mm; on the right side 4.1 diameter 45 mm, 4.1 diameter
48 mm. We used a microunit-type abutment 17 with a height
of 4 mm, so as to have the emergence profile located in the
molar region. Because the torque was greater than 40 Ncm for
the implants in both arches, an immediate loading protocol
was initiated, tissue was sutured, and acrylic resin (Duralay,
Reliance) was used to secure the abutment transfers in both
Fig. 1. Patient 1. A, Intraoral photograph. B, Initial radiograph. C, A channel or slot was completed to define the orientation of
the trajectory of the drills. D, Zygomatic and conventional implants installed. E, Postoperative radiograph. F, Clinical photograph
showing the final prosthetic result. G, Radiographic follow-up at 24 months.
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arches and an impression for manufacturing the prosthesis
was completed. After 48 hours, the prosthesis was installed,
reestablishing the function and esthetics for the patient. Pan-
oramic radiographs were performed at 24 and 48 months for
the control treatment (Fig. 2, A-H).
DISCUSSIONAfter extractions, the process of bone remodeling in
the jaw suffers, causing inadequate dimensions for im-
plant placement. This atrophy is physiological and oc-curs in a chronic and irreversible fashion.6 The lack of
internal pressure along with posterior tooth extractionleads to bone resorption of the edentulous alveolar
ridge, making the retention of functional prosthesesdifficult and can lead patients to a disabled state in their
mouth with a decreased quality of life.20,21
Patients with major destruction of the premaxilla,maxillary sinus pneumatization, or defects owing totumor resection have limitations on treatment with oral
implants. Maxillary bone atrophy is classified by sev-eral authors19,20,21 as a major challenge, with a high
difficulty of rehabilitating a severely resorbed maxilla,indicating a major reconstruction with autogenous bone
grafts using extraoral donor sites,22 subsequent to theplacement of implants or anchoring techniques, without
bone reconstruction.The reconstruction techniques involve an increase in
the jawbone structure, aiming at the application of
conventional fixation in places where there is sufficient
alveolar height and thickness, providing the use of
implants in a much better position and, consequently,
better biomechanic distribution. The reconstructionscan be made on the alveolar ridge (onlay) or within
cavities, particularly the sinus (inlay).22 The grafts have
inevitably some element of risk, because they demand
good surgical technique, good quality of recipient bone,
soft tissue overlying the graft, great cooperation from
the patient, and general health of the patient that en-
courages healing.23 The literature shows a variability in
the survival percentage of the different techniques of
bone grafting being 80% to 95%,24-26 with a follow-up
time of 12 to 124 months. It also reports that the
success rate of implants in bone grafts is 74% to
87%.27-29
Initially, the ZI was designed to treat patients suffer-
ing from trauma or surgically resected tumors, where
there is great loss of jaw structures.11,23,30 Subse-
quently, the technique was applied to patients with
severe maxillary atrophy to simplify the treatment and
avoid a reconstruction.31 There are different techniques
for fixation of zygomatic implants, including the orig-
inal technique by Brnemark, which recommends
opening a window on the wall of the maxillary sinus as
well as maintaining the integrity of the sinus mem-
brane. The first case used a protocol originally pro-
Fig. 2. Patient 2. A, Intraoral photograph. B, Initial radiograph. C, Extrasinus zygomatic implant. D, Four zygomatic implants.
E, Clinical photograph. F, Postoperative radiograph. G, Final result (a, intraoral; b, extraoral). H, Radiographic follow-up at 48
months.
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posed by the Stella technique with the use of a channel
or slot through which the implant installation is guidedinto the sinus, eliminating the bony window and the
sinus lifting, having a larger implantbone interfacewith a vertical orientation and better emergence place-
ment of the implant closest to the crest of the alveolar
ridge. In the second case study, the extrasinus zygo-matic implant technique traces an imaginary line fromthe insertion point on the ridge to the point of attach-
ment to the body of the zygoma and the implant can becompletely or partially outside the sinus cavity. The
choice of technique is determined by the patients boneanatomy as well as technical skill of the clinician.
The zygomatic implant requires care in relation tothe biomechanical forces of curvature, whose forces
may impair the long-term stability of an implant-sup-ported restoration and, because of this, there must be
stiff prosthetic work, because flexing of the materials
used can cause deformation and deviation resulting inloss of fixation of the implants or loosening of the
junction between the prosthesis and fixation.32
The use of immediate loading with the 1 or 2 ZI on
each side is justified by some authors because theybelieve that the quality of the zygomatic bone, the rigid
stabilization and polygons created in the technique,coupled with the benefits provided to the patient (less
time, less cost, and possibility of social life) allows thisprocedure to be used.33,34 The use of prototypes seems
to be an interesting tool in the planning of this tech-nique, but high cost still hampers its use.35 An impor-
tant question is what could cause the presence of zy-gomatic implants inside the maxillary sinus. A study by
Nakai et al.36 in 2003 reported using computed tomog-raphy scans, performed 6 months after the installation
of 15 zygomatic implants, in 9 patients and showed nosigns of sinusitis. Petruson, in 2004,37 evaluated the
zygomatic implants in the maxillary sinus through asinuscopy in 14 patients, finding no infection or inflam-
mation in the mucosa around the implants.The success rates of implants in the zygomatic bone
vary from 95% to 97% with 12 to 124 months offollow-up observation,16,19,23,36-42 and a patient satis-
faction rate of 80% after 1 year of installation of theprosthesis.43
CONCLUSIONSClinically, the technique of zygomatic implants is an
excellent therapeutic modality for patients with atro-phic maxillas wishing to avoid a bone graft and there-
fore increasing predictability and reducing costs andmorbidity of treatment. The most important point in
this procedure is the clinical mastery of the techniquesfor this surgical approach, determining the success of
the treatment.
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Reprint requests:
Ernesto Barquero Cordero, PhD
Rua Duarte Schuttel 262, Ap 301
Centro, Florianpolis
Santa Catarina, Brasil 88015-640
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mailto:[email protected]:[email protected]