Background information
Dr. Zvi Artzi:
«Several studies have shown that the success rate of osseointegrated implants
placed in grafted maxillary sinuses is comparable to implants in non-augmented sites (1- 3). Bio-Oss® has been extensively investigated in the literature
for sinus floor augmentation (4 - 26).»
Harvesting autogenous bone
When the lateral sinus wall is relatively thick (2 mm), as determined by the CT scan,
corticalis chips can be harvested from the surgical site. Otherwise, autogenous bone
chips can be collected by labial plate scraping of the lateral posterior area of the
mandible near the external oblique line with the use of a manual scraper. Following
local anaesthesia of the long buccal nerve, a blunt incision is made on the lateral
posterior part of the mandible extending from the buccal masticatory mucosa to the
ascending ramus with a Bad-Parker No.15 c blade. A full thickness flap exposes the
lateral retromolar mandibular bone area. By using the bone scraper, numerous bone
chips are harvested from the corticalis. The chips are mixed in a 1:1 ratio with BioOss® particles (0.25 - 1 mm in size), and blood is added for moisture.
Fig. 6 The grafting material is applied in
two increments, before and after implant
placement. The first portion of the grafting
material is applied through the fractured
wall orifice.
2. Main emphasis of this case presentation
> Step by step surgical procedure of sinus floor augmentation with Bio-Oss® and
autogenous cortical bone chips simultaneously with implant placement, by using a
surgical guide stent.
3. Surgical procedure
Premedication
Fig. 7 The implants are placed.
Fig. 8 Subsequently, the second portion of
the grafting material is applied to achieve
complete obturation of the window.
Fig. 9 Bio-Oss® particles are also added to
augment the lateral aspect of the mesial
implant, followed by an occlusive bioresorbable membrane (Bio-Gide®) to cover the
entire area.
Fig. 10 Primary tissue closure is achieved
using a non-absorbable 4-0 suture. Soft tissue healing was uneventful.
Fig. 11 Radiographically, Bio-Oss® particles
are observed during the follow-up .
Fig. 12 Upon re-entry after 6 months, a
dense osseous tissue inhabits the previous
lateral window area.
Fig. 13 Implant cover screws are exposed.
Note the thick osseous tissue (arrow) established at the buccal side of the mesial implant which was augmented with Bio-Oss®.
Fig. 14 The final prosthesis (courtesy of Dr.
Jenny Chernobelsky).
Fig. 15 The functional osseointegrated implants are surrounded by regenerated bone.
The new location of the sinus floor is well
established above the augmented area.
Premedication follows the protocol suggested by Misch (4): Dexamethasone 9 mg
before surgery, 6 mg after 24 h and 3 mg after 48 h as an anti-inflammatory drug.
Systemic antibiotics are administered 1h pre-op (Amoxicillin 1g) and for one week
(500 mg QID). NSAID drug like Ibuprofen (400 mg) or Etodolac (400 – 600 mg)
should be prescribed. Local anaesthesia by buccal and palatal infiltration of 3 %
Lidocaine and 0.04 mg base Norepinephrine is administered.
Fig. 1 Preoperative panoramic radiograph
shows a pneumatised sinus with moderate
atrophic residual ridge bilaterally. A CT scan
enables a three-dimensional evaluation.
Fig. 2 Surgical stent is adjusted (fabricated
by Dr. Jenny Chernobelsky).
Fig. 3 The stent guides accurate positioning
of the gauge pins during the implant site
preparation.
Fig. 4 The lateral bony wall is exposed with
a vertical releasing incision to allow an extensive mucoperiosteal buccal flap at the
edentulous posterior maxillary region. The
contour of the lateral window is demarcated by a 2 mm diameter round diamond
bur, average 8-12 mm (H) x 12-20 mm (W).
Membrane elevation
Surgical aftercare
Fig. 5 As the Schneiderian membrane is exposed, a broad flat curette is pushed gently between the membrane and the inner bony wall to separate, release, and loosely reflect the
membrane. The fractured bony wall is pushed inward and upward where the superior margin serves as a hinge ‹green stick fracture› of the window. This also eases a harmless membrane reflection. The Schneiderian membrane is elevated and a space between the reflected
sinus membrane and the floor of the antrum is established.
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Anti-inflammatory drug: 6 mg Dexamethasone after 24 h and 3 mg after 48 h
Systemic antibiotic: 500 mg Amoxicillin (TID) for 1 week
Analgesis: Etodolac 200 mg or Ibuprofen 200 mg – every 6 – 8 h as needed
Antiseptic mouthwash: 0.2 % chlorhexidine gluconate for 30 – 45 s, 2 / day
Suture removal after 14 days
Augmentation/implantation on the contralateral sinus - at least one month interval