Background information
Dr. Matteo Chiapasco:
A 40-year old male, healthy and non-smoker, was referred for assessment of the possibility to restore
the missing dentition in the maxillary arch (teeth 16 and 15) with an implant-supported fixed partial
prosthesis. Initial clinical and radiographic (panoramic and intraoral radiographs) examiation
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revealed however, that a vertical and horizontal bone defect was present (Figures 1-4). Moreover, the
patient had a high smile line in the posterior maxilla on both sides (Figures 5-6), high aesthetic
expectations, and did not accept any compromise in terms of the final outcome of the prosthetic
restoration. In order to optimize the final outcome, consultation with the prosthodontist was
requested. Impressions were taken and, on the plaster model obtained, a waxing-up was performed.
Placing teeth in the ideal position, a discrepancy appeared between the residual bone and the final
restoration (Figure 7).
The CT scans done with a diagnostic template including radiopaque landmarks constructed on the
waxing-up confirmed resorption of the alveolar ridge at the level of the missing dentition, both in the
vertical and horizontal dimension. This situation precluded the possibility of placing implants in a
proper, prosthetically driven position. Obtaining an adequate restoration of the missing dentition
from a functional, and specifically from an aesthetic point of view was challenging (Figures 8-9).
The surgical plan first included a reconstruction with autologous bone blocks taken from the
mandibular ramus, in association with the use of bovine bone mineral (Geistlich Bio-Oss®, Geistlich
Biomaterials, Wolhusen, Switzerland) and a native resorbable collagen membrane (Geistlich BioGide®, Geistlich Biomaterials, Wolhusen, Switzerland) to correct both vertically and horizontally the
deficient alveolar ridge and to facilitate bone gain over time (Figures 9-20). Placement of 2 implants
was planned in a second stage procedure, 4 months later (Figures 21-25). Finally, after another three
month period, the prosthetic restoration was started. After another 3 month period necessary to
condition soft tissues, the final prosthesis was delivered (Figures 26-29). A radiographic control 2
years later showed stability of periimplant bone (Figure 30).
> estore adequate bone volume of the edentulous ridge.
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> ptimize intermaxillary relationships.
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> ptimize the final prosthetic result from a functional and aesthetic point of view.
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Fig. 8 A diagnostic template is fabricated following
the indications of the pre-op waxing -up.
Fig. 9 CT scan performed with the diagnostic
template in the mouth confirmed the bone defect
between the ideal position of prosthetic crowns
and the residual alveolar bone. Without reconstruction, the implant would be placed too far apically
and palatally, thus rendering the final prosthetic
result mediocre.
Fig. 19 A tension-free and water-tight suture has
been performed to prevent dehiscence of the
surgical wound and potential contamination of the
grafted area, which may otherwise lead to complete
loss of the graft.
Fig. 20 Postoperative radiographic control
immediately after the reconstruction showing the
augmentation obtained.
Fig. 21 Clinical control three months after surgery:
an excellent correction of the defect and the proper
intermaxillary relationship is clearly visible.
Fig. 10 To harvest an autogenous bone block from
the mandibular ramus for the reconstruction of the
maxillary defect, a full thickness flap is raised after
an incision which follows the ascending ramus of
the mandible. The ascending ramus is exposed, an
autogenous bone segment is outlined with fissure
burs assembled on a low-speed straight handpiece,
and finally it is detached with the aid of a surgical
chisel.
Fig. 11 The bone segment harvested from the ramus
must be shaped now according to the bone morphology of the recipient bed.
Fig. 12 An oscillating saw is used to separate the
block in different pieces. Two pieces will be used as
blocks for the vertical and horizontal reconstruction. One piece will be transformed into particulated bone.
Fig. 22 Four months afterwards, the patient is ready
to receive implants. After the elevation of a partial
thickness, epiperiosteal flap, not to expose the
underlying graft, fixation screws are removed.
Fig. 23 Following the indications of the previously
fabricated template, implant sites (2) are prepared
in a prosthetically driven and optimal position.
Fig. 24 Two implants, 4.1 mm in diameter and 10 mm
in length (Straumann Bone level implants, Institut
Straumann, Basel, Switzerland), are inserted in the
reconstructed area.
Fig. 13 Transformation into particulated bone is
obtained by means of a bone microtome.
2. Aims of the therapy
Fig. 7 Preoperative waxing-up demonstrates that
a
reconstruction of the resorbed alveolar ridge is necessary, to maintain the teeth to be prosthetically
restored with appropriate dimensions (length, in
particular) compared to the neighboring dentition
and to the corresponding teeth on the opposite
side.
Fig. 14 The autogenous bone chips obtained after
particulation of a bone block. The particulated bone
will be used to “pack” every empty space between
the recipient site and the bone blocks and to cover
“steps” between the graft margins and the recipient
bed.
Fig. 15 After elevation of the mucoperiosteal flap,
the maxillary defect is exposed and a first block
of autogenous cortical bone is stabilized with two
titanium microscrews to correct the vertical defect.
Fig. 25 Radiographic control immediately after
implant placement.
Fig. 26 The final prosthetic result showing optimal
occlusion and morphology of the implant-supported
crowns.
Fig. 27 Close-up of the implant-supported restoration of teeth 15 and 16, with very good integration
with the neighboring dentition.
Fig. 16 A second block is fixed in the same manner
to correct the horizontal defect. Any gap between
the recipient site and the blocks must be filled with
particulated autogenous bone, to avoid penetration
of connective, fibrous tissue during healing which
may compromise the graft integration.
Fig. 17 A mixture of autogenous particulated bone
and bovine bone mineral (Geistlich Bio-Oss®) is used
to cover the bone blocks and to cover steps between
the margins of the grafts and the recipient bed. This
procedure will simplify the contouring of the graft.
Fig. 18 The grafts (blocks and particulated bone +
Geistlich Bio-Oss®) are covered with a resorbable
collagen membrane (Geistlich Bio-Gide®) in order to
stabilize the particulated graft and to reduce the risk
of bone resorption.
Fig. 28 During patient’s smile, an almost perfect
symmetry is visible between the reconstructed and
prosthetically restored site and the contralateral one
with natural dentition.
Fig. 29 Radiographic control after the completion of
the restorative procedure.
Fig. 30 Radiographic control two years after the
completion of the prosthetic rehabilitation, showing
stability of implants and the periimplant transplanted
bone.
3. Surgical procedure
Fig. 1 Preoperative panoramic radiograph showing
missing dentition at level 15-16.
Fig. 2 Preoperative intraoral radiograph shows
apparently enough bone below the sinus to allow
placement of two short implants at least 6 mm long.
Fig. 3 Intraorally, a moderate vertical resorption of
the alveolar ridge is visible.
Fig. 4 Moderate horizontal resorption of the ridge is
also visible.
Fig. 5 The high smile line in the posterior maxilla
and the high aesthetic expectations of the patient,
contraindicate the use of short implants with longer
crowns. This would create a relevant “asymmetry”
in teeth length on the right and left sides, with a
less than ideal result.
Fig. 6 Lateral view of the smile line on the right
side shows vertical resorption of the alveolar ridge
behind tooth 14.
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