Sandwich bone graft for vertical augmentation of the posterior maxillary region: a case report with 9-year follow-up
Tanaka et al. International Journal of Implant Dentistry
Sandwich bone graft for vertical augmentation of the posterior maxillary region: a case report with 9-year follow-up
Kenko Tanaka 0 1
Irena Sailer 0
Yoshihiro Kataoka 1
Shinnosuke Nogami 1
Tetsu Takahashi 1
0 Division of Fixed Prosthodontics and Biomaterials Clinic of Dental Medicine, University of Geneva , 19 rue Barthélemy-Menn, CH-1205 Geneva , Switzerland
1 Division of Oral and Maxillofacial Surgery, Department of Oral Medicine and Surgery, Tohoku University Graduate School of Dentistry , 4-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Miyagi , Japan
The loss of teeth followed by bone resorption often lead to defects in the alveolar ridge, making installation of dental implants difficult. Correction of such bone defects, especially lack of height of the ridge, is a difficult problem for all dental surgeons. This report describes the outcome of treatment after alveolar ridge augmentation in the atrophic posterior maxillary region via segmental sandwich osteotomy combined with placement of an interpositional autograft prior to placement of endosseous implants. The technique was successfully used to treat a deficiency in the vertical dimension of the posterior maxillary region. Six months after graft surgery, two implants were successfully placed in accordance with the original treatment protocol, and they survived for 9 years of follow-up.
Bone graft; Long-term follow-up; Interpositional bone graft; Sandwich graft
Osseointegrated implants for the replacement of missing
teeth have recently become a routine treatment option
[1, 2]. However, any tooth loss may be followed by
extensive resorption of the alveolar ridge, which usually
makes implant placement difficult or impossible because
of the lack of bone volume. There are a variety of defect
situations with increasing complexity, ranging from
fenestrations, to dehiscences, to both horizontal and vertical
deficiencies, while combinations of these also occur. Ridge
augmentation techniques are available to effectively
and predictably increase the width of the alveolar ridge
in horizontal deficiencies. If vertical deficiencies are
present, including in combination, the predictability of
the techniques is usually substantially lower . A
significant bone defect is an anatomical limitation that
can be overcome using different surgical techniques,
including vertically guided bone regeneration. Several
techniques are currently employed, using some
combination of autologous bone or biomaterials, various vertical
guided bone regeneration (GBR) procedures [4, 5], alveolar
distraction osteogenesis , titanium mesh , and onlay
bone graft .
While the vertical augmentation of the bone has been
demonstrated with different techniques, the number of
complications and failures of the augmentation procedure
is still too high to recommend a widespread use of such
procedures [9–11]. In addition, vertical augmentation
procedures on compromised alveolar ridges are technically
sensitive and might cause significant postoperative
morbidity and complications, such as severe postoperative
pain, swelling, or graft resorption. Furthermore,
augmentation procedures always increase cost, morbidity, and
treatment time .
Recently, rough-surface implants made with new
technology have demonstrated better mechanical and
biologic characteristics than traditional machined-surface
implants. Several clinical studies have demonstrated high
success rates and predictable clinical outcomes for
placement of short implants. Short implants have been
proposed as an alternative to avoid the problems associated
with vertical augmentation [12–14]. Still, there is a need for
more clinical studies to support this recent concept.
In the literature, the technique of segmental osteotomy
accompanied by interpositional grafting has been
reported as a practical and predictable procedure with a
low incidence of complications and a high probability of
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success [15–19]. This approach leaves the soft tissue on
the oral side of the midcrestal incision attached to the
crestal bone segment. Various studies have shown that
alveolar osteotomy associated with interpositional
grafting may be an effective alternative to other surgical
techniques for increasing vertical bone height in the
posterior maxilla and mandible [15–19]. The technique
is based on interposing a bone graft between
osteotomized bony segments, which act as a “sandwich,”
offering good vasculature to both the segment and the graft
and resulting in less bone resorption compared to the
methods described before [15–19].
This case report describes clinical treatment using
segmental osteotomy with interpositional bone grafting to
rehabilitate the alveolar ridge in the posterior region of
the maxilla with 9 years of follow-up.
A 67-year-old male patient sought implant rehabilitation
for the purposes of restoration of occlusal support and
assistance with chewing difficulties. Clinical and
radiological examinations revealed that teeth were absent
26–27. The clearance from the alveolar ridge to the
opposing teeth was 20 mm (Fig. 1). A CT scan showed
that the distance from the reabsorbed ridge to the floor
of the maxillary sinus was approximately 26: 6.1 mm
and 27: 7.5 mm, and the width of clearance was
approximately 8 mm. The alveolar bone defect in this case
was the loss of ridge height with normal ridge width, class
II according to the Seibert classification . Additionally,
septa and a thickened sinus membrane were evident
within the maxillary sinus (Fig. 2).
As a preoperative diagnosis, it was determined that the
septa and a thickened sinus membrane meant that sinus
lift augmentation was difficult, and bone augmentation
to the crown side was required, but the morphology of
the alveolar ridge had been well maintained. The
treatment options included using short implants, but
evidence on their long-term outcome was still limited at
It was determined that the best treatment involved
segmental osteotomy and placement of an interpositional
graft using the bone removed from the ramus of the
mandible to restore the posterior maxillary alveolar ridge, prior
to placement of dental implants.
The operative procedure was performed after the
induction of general anesthesia using a 1/160,000 xylocaine
solution with epinephrine 1:100,000. A linear incision was
made 3 mm above the mucogingival junction. The
mucoperiosteum was detached, and the vertical and horizontal
osteotomies were prepared using micro-saws. Chisels were
used to finalize the osteotomies and to mobilize the bony
segment. Care was taken not to damage the palatal
mucosa. The surgery proceed to the removal of a bone graft
Fig. 1 Preoperative intraoral photograph and radiograph
block (17 × 10 × 4 mm) from the ramus of the left
mandible and the adaptation thereof to the recipient site with
the cortical portion facing the vestibular side (Fig. 3). The
device formed by the mobilized bone segment and the
interposed bone graft block was fixed using WY-type
microplates and screws (Stryker Japan, Tokyo, Japan). Crushed
autologous bone was applied to the region of the graft
Fig. 2 Septa and thickened sinus membrane within maxillary sinus
(Fig. 3). The procedure was finalized using a running stitch
for closure with 5-0 nylon catgut.
Six months after surgery, radiological examinations
were carried out and the patient underwent implant
placement (Fig. 4). The postoperative bone height had
increased to 10.1 mm at position 26 and 12.9 mm at
position 27 compared with the preoperative heights of
6.1 and 7.5 mm, respectively. Postoperative clearance
was reduced by 11 mm compared with the preoperative
clearance. Careful separation of the mucoperiosteum
revealed that the fixation device was in the right place, the
interpositional bone graft had been incorporated, and
gains in the height and thickness of the alveolar ridge
had been achieved. The fixation system was removed,
and two dental implants (4.5 × 11 mm) (Astra Tech AB,
Mölndal, Sweden) were placed in accordance with the
Fig. 3 a A paracrestal incision was made on the buccal side, and
horizontal and vertical osteotomies were made with a piezo-electric
device. b Placement of the ramus bone block as an interpositional
graft. c Ramus bone graft fixed
original treatment protocol under the relevant surgical
guidance (Fig. 5). Three months after implant surgery,
the temporary prosthesis was fixed, and after a further
3 months, the final prosthesis was fixed (Fig. 6). The
postoperative course was uneventful for 9 years after
surgery (Fig. 7).
This paper reports on a segmental osteotomy procedure
with an interpositional graft in the posterior maxillary
region with 9 years of follow-up.
The techniques used to overcome a lack of alveolar
bone height rely on the placement supplemented by
various vertical guided bone regeneration (GBR)
procedures [4, 5] and the use of alveolar distraction
osteogenesis , titanium mesh , or onlay bone graft . Gains
in ridge height of between 3.6 and 9.2 mm depending on
the materials used have been reported, and these were
associated with 5-year implant survival rates of 97 to
100%, depending on the method employed . On the
other hand, it has also been reported the number of
complications (e.g., flap dehiscence, barrier exposure) and
failures of the augmentation procedure (e.g. infection,
graft bone necrosis) [3–8]. Additionally, the biomaterials
used as substitutes for the bone require a longer healing
time than autologous bone because the substitutes in
general are not osteoinductive .
Fig. 4 Preoperative and postoperative radiograph
Although a certain amount of slow appositional bone
growth from the bony walls into the defect is observed,
this growth depends on the growth of new blood vessels
between each particle. In the alveolar crest, it
spontaneously stops at a distance of few millimeters above the
defect bone wall. The more distant particles instead heal
within fibrous tissue to form a scar. This is expected to
have a negative effect on the long-term survival of the
The use of short implants is another possibility when
alveolar bone height is inadequate for regular implants.
The use of such implants can reduce treatment time,
cost, and postoperative morbidity compared to bone
augmentation procedures. The first EAO consensus
conference (2006) had defined short implants as a device
with a design intrabony length of 8 mm or less  and
had demonstrated high success rates and predictable
clinical outcomes for placement of short implants [12–14],
but there were still controversies regarding the long-term
consequences of peri-implant bone loss around short
implants and its impact on the long-term implant success
rate at that time.
In this case, the alveolar ridge was Seibert class II, and
septa and a thickened sinus membrane were evident
within the maxillary sinus. Sinus floor elevation was
limited because of the condition of the floor morphology,
the presence of septa, and the thickness of sinus floor
membrane [22, 23]. Considering these issues, we selected
the interpositional bone graft technique using autologous
bone in preference to short implants or the use of a
The inlay bone graft technique, first described by
Schettler and Holtermann in 1977  which presented
the reconstruction of a severely atrophic edentulous
mandible, has great potential for bone graft incorporation.
The technique is relatively simple and provides satisfactory
Fig. 6 Application of final fixed prosthesis
results both in terms of surgical success and predictability
[15–19]. The technique is predicable because the four
walls of the graft are in contact with live tissue, increasing
vascularization and reducing resorption . A box-style
gap opens between the segments, which borders on an
open bone marrow cavity on two sides. This space offers
excellent conditions for vascularization of the graft and
bone healing. Thus, a temporary prosthesis can be used
in the early postoperative period. Since that first report,
Fig. 7 Nine-year follow-up radiograph of the implants
several reports on research outcomes, technological
progress, and the good results obtained with this technique
have been published. This technique is now regarded as a
good way to correct vertical deficiencies prior to
placement of dental implants [15–19].
On the other hand, alveolar augmentation depends on
the operator’s experience and is technically sensitive .
The most common difficulty is how to manage the soft
tissues to preserve the blood supply to the cranial segment;
releasing incisions make tension-free closure possible so
that the segment does not move palatally.
Nevertheless, in this case, the procedure was carried
out successfully, and two regular implants were
successfully placed in the alveolar ridge after its enhancement
with an autologous bone graft. Those implants survived
over 9 years of follow-up.
We described in the present case a vertical lack of the
bone from the alveolar ridge to the opposing teeth, the
short distance from the reabsorbed ridge to the floor of
the maxillary sinus, and the presence of septa and a
thickened sinus membrane within the maxillary sinus.
A sandwich bone graft was successfully applied and
followed up in the long term. The resulting gains in
ridge height and increased thickness of the alveolar
ridge appear to have been sufficient for effective
placement of the implants, given that these implants have been
maintained for 9 years since surgery.
Authors Kenko Tanaka, Irena Sailer, Yoshihiro Kataoka, Shinnosuke Nogami,
and Tetsu Takahashi declare that they have no competing interests.
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