Application

1. Crestal longitudinal incision and mucoperiostal flap opening

2. Implant drilling down to 1 – 2 mm above the sinus floor

Starting with an used pilot bur with poor grinding capacity in order to feel better the sinus corticalis

3. Thinning of the sinus corticalis with a round diamond bur

At a residual bone height of 3 mm or less the diamond drill makes an opening without any prior implant drilling

4. Three to four marginal predetermined breaking points are made with a fine, convex osteotome.

5. Breaking through the sinus floor, penetrating at most 1 – 2 mm into the sinus, first with the convex osteotome…

… then with the concave osteotome.

6. Circular detachment and lifting of the sinus mucosa with the Benex sinus elevators to about five millimeters

7. Widening of the implant bed with profile drill. The business end of the drill must be rounded.

8. Further elevation of the sinus mucosa with the Benex elevators up to the desired implant length

9. Profile drilling for the implant’s end position

10. Vibrating, the bone substitute is introduced under the sinus mucosa with the finest, convex osteotome.

Insertion of the coronal-tapered implant (X-ray postop)

Wound closure (situ 10 days postop)

Contraindications

In general medical terms the same contraindications apply as for all other implantations.

Locally there are no contraindications:
neither osseously-related  (low subantral bone height, sinus septa, sloping sinus floor)
nor mucosa-related (acute sinusitis requires one week of antibiotic pre-treatment).

Medicines

The same medication as with all other implantations.

• Rinsing one minute with 0.2% Chlorhexidin,
• preoperative and for 1 to 2 weeks 3-4x a day
• Clavulanic acid/Amoxicillin, 1 g preoperative
• Pain medication as required: Paracetamol 1 g or mefenamic acid 500 mg

Imaging

No special imaging is indicated such as CT or DVT.
A single x-ray image showing the subantral bone in the implantation area is enough.

Incision

Access by mucosa punching presents no problems.
But a small opening of a mucoperiostal flap has considerable benefits:

• The periodontium of the adjacent teeth can be examined and, if need be, cleaned.
• The surface of the ridge can be smoothed.
• A thick submucosa can be thinned.

Peri-implant vestibuloplasty

In the posterior maxilla region the vestibulum is often flattened and cheek ligaments inserted high on the ridge.
A localized vestibuloplasty creates favorable peri-implant mucosa conditions.

The mucosa is incised along the linea girlandiformis (with a scalpel) and detached from the periosteum towards vestibular (with scissors).
The mucosa split flap is moved towards vestibular and fixed to the periosteum with a wide, horizontal mattress suture.

Thinning the mucosa

The mucosa is frequently very thick in the posterior maxilla region.
It is thinned to 3 to 4 mm by excising submucosal tissue during the opening.

Transmucosal healing, suture technique

The suture technique shown provides the most predictable primary wound healing for transmucosal implant healing.

Transmucosal healing enables precise hollowing for the plate temporaryrestoration  and makes re-opening irrelevant.

The mucosa flaps are fixed around the implant with a horizontal mattress suture, in combination with a single-button suture (Laurell suture). The retromolar relief incisions are sealed with only one mattress suture.

General

The transcrestal sinus lift shown here only has the crestal access in common with the classical Summers technique.
The Summers technique is invasive and uncontrolled: hard hammer blows compress bone and press it into the sinus.
In the presented transcrestal sinus lift method the osseous access is made in a minimally invasive and controlled manner like opening with the lateral fenestration technique.

Summers technique: invasive, uncontrolled

Presented method: minimally invasive, controlled

Subantral bone height of less than 3 mm

Osseous opening with the diamond drill. This can, of course, be done with piezo surgery.

After the sinus mucosa elevation of about 5 mm, the profile drilling is done for the definitive implant position.

Subantral bone height of more than 3 mm

• the cylindrical implant drill (ascending to the diameter of the implant)
• sinus floor thinning with diamond drill
• predetermined breaking point trephinations with the finest convex osteotome
• breaking in the sinus floor with a wide convex osteotome
• preparation with a broad convex osteotome
• definitive profile drilling

1. Preparation with the cylindrical implant drill.
Starting with an used implant pilot drill with poor grinding capacity. Close to the sinus floor you can feel increased resistance. The following drillings with the larger drill diameters must not go deeper.

2. Thinning the sinus corticalis
Careful grinding with the diamond drill, as long as bone resistance is felt. Inspect with a mirror: the cortical bone is poorly vascularized, whitish.  If thinning is sufficient, you can see the shimmering bluish Meissner’s membrane.

3. Predetermined breaking point trephinations
Using the smallest convex osteotome make three to four trephinations in a diagonal direction as parallel as possible to the sinus floor contour. The hammer blows are very fine, you can feel and hear the perforation. The osteotome penetrates slightly into the maxillary sinus.

4. Sinus floor trephination with the broad convex osteotome
The prepared channel depth is measured (small osteotome).
The sinus floor is perforated (fine, short hammer blows) using the broad, convex osteotome, 2 mm at most above the measurement that was made

5. Channel enlargement with the broad concave osteotome
The broad, concave osteotome is also introduced with fine, short hammer blows into exactly the same depth as the convex osteotome.

Detaching, elevating the Schneider’s membrane

Detach and elevate the Meissner’s membrane using the Benex sinus elevators.
The fine membrane rests on the sinus floor with a virtual slit.
The elevator’s own weight is enough to detach/elevate the mucosa.
Expose the mucosa at a low subantral bone height without osteotome (like the fenestration technique). Before inserting the sinus elevators here, detach the membrane circularly with a fine instrument.
In opening the access with the osteotome, the mucosa is detached circularly during insertion of the convex osteotome and the sinus elevators can be directly inserted.

While elevating the mucosa, the end of the instrument always has to maintain contact with the bone. Elevate the mucosa circularly with the back of the instrument.
The four different lengths/curvatures of the elevator shaft enable trouble-free, circular work to be performed.

Relining the elevated Schneider’s membrane with bone substitute

0.5cc of xenogeneic bone substitute without autologous bone is used as augmentation material.
BioOss: 0.25g/0.25mm-1mm
BioOss offers an excellent augmentation ossification/remodelling.

Place BioOss in a sterile dish, moisten with NaCl and insert with the periosteum elevator.  The BioOss particles are hydrophilic and can be transported well with the elevator.
Distribute the bone substitute beneath the sinus mucosa with the finest, convex osteotome, vibrating at the same time.
Before screwing in the implant, remove the BioOss particles from the implant channel with an excavator.

Managing a perforation of the Schneider’s membrane

The incidence of mucosa perforation was 15.3% in the study cases (see below). In the premolar region it is much higher than in the molar region, probably due to the sloping sinus floor and the steep buccal and palatal walls.
Overall, I estimate the incidence for a perforation to be about 12%.

The rupture was able to be covered with a collagen membrane (BioGide) in every case and the sinus lift/implantation completed in one sitting.
The loss rate was not significantly increased due to the perforations.

Procedure for a perforation treatment

The nose blowing test has to be performed often so that the rupture can be recognized promptly and kept small.
In the nose blowing test a person has to inhale and exhale with a closed nose in order not to produce a false negative result.
The site of the rupture is located. It can be seen or the escaping air outlet indicates the location.
The Meissner’s membrane is temporarily elevated opposite the site of the rupture and then further elevated around the site of the rupture coming from the periphery.
This succeeds in getting the perforation into the center and it gets smaller.
The perforation is covered with a collagen membrane (BioGide), bone substitute (BioOss) introduced and the implant inserted.

Temporary dental prosthesis

Often no temporary dental prosthesis is required in the posterior tooth region.
At the lowest subantral bone height hard food is meant to be chewed on the opposite side.

If there is a prosthesis, it has to be hollowed well.
There is no difficulty in this with transmucosal healing.
The healing cap can be identified in the prosthesis with Fit Checker where it can be generously hollowed, see Galery below.

In the premolar region a bridge section for the implantation can sometimes be removed leaving little residual substance and be supplemented with plastic after wound closure, see Galery below.

The suprastructure of an implant

The first priority of forming a suprastructure is facilitating trouble-free dental hygiene.
A free end gap restoration is mostly restored with a “sixer” occlusion. Absent premolars and molars are replaced with a tripartite implant bridge (implantation in the four and six area), and a missing premolar and molar with a winged bridge.
Intermediate gaps under 16 mm in width are restored with a winged bridge and over 16 mm with a tripartite bridge.

Vertical ridge deficit, low subantral bone height

The natural atrophied ridge usually causes a vertical and rarely a transversal ridge deficit in the anterior maxilla.

This produces a low subantral bone height.
At the smallest subantral bone height the transcrestal sinus elevator method presented permitted a single-session procedure with assured primary stability of the implant.

Bucco palatal ridge defect

The bucco-palatal ridge defect in the maxilla is frequently caused iatrogenically through damage during the extraction.

After placement of the implant with sinus lift, the ridge is augmented with bone substitute (BioOss) and collagen membrane (BioGide).

Sinus septa, sloping sinus floor

Sinus septa or a sloping sinus floor are frequent and are not a contraindication for transcrestal sinus lift.

The septum usually runs from palatal to buccal.
Preoperative imaging is not required.
During opening the septum is ablated with the diamond drill.
Deeper in the channel a septum or a sloping sinus floor are gradually absorbed with the osteotome. This is done while alternating with the elevation of the surrounding, exposed Schneider’s membrane.

Large ridge defect after invasive extraction

Major ridge defects, often caused by invasive extraction, are augmented with bone substitute (BioOss) and collagen membrane (BioGide). See also bucco-palatal ridge defect.

After an extraction/explantation with sinus perforation there often remains an osseous sinus floor defect.
When opening a mucoperiostal flap the Schneider’s membrane can be lacerated.
The membrane is detached around the site of the rupture, elevated and covered with a collagen membrane like the coverage of an accidental rupture during sinus lift.

The sinus augmentation (BioOss) is very well ossified.
The volume of the augmentation remains constant in the first year postoperative and shows a remodeling in the following years.  After some years the augmentation structure can hardly be differentiated any more radiologically from the surrounding bone.

The histology of a BioOss augmentation cylinder, nine months after sinus augmentation, shows how the BioOss particles are “ossified” without any signs of inflammation.

The picture gallery shows radiological progress checks on the sinus augmentation.
A scientific reappraisal is in preparation.

Most of the x-ray images shown here come from patients who were referred for a different maxillofacial implant procedure after sinus lift.

The failure rate is very low, 1.2% in my observation study (2001 to 2006)
The whole loss rate after 1 to 15 years is under 2% (estimate).

Late losses after several years are almost exclusively caused by peri-implantitis.
The etiology of the early losses (missing osseointegration) is unclear because of the low number of cases.
The risk of loss is high in situations without primary stability.

With all implant losses the sinus augmentation had ossified so well that there could be a successful reimplantation three to five months after the explantation.

Case 1

Early loss: The ossified augmentation allowed a simple reimplantation without sinus lift.

Case 2

Missing primary stability.
Despite high risk of loss implantation was performed at one sitting as in several cases with missing primary stability the implant osseointegrated without any trouble and in case of a loss a simple reimplantation can be performed.

Case 3

Loss likely because of insufficient hollowing of the full prosthesis.

The implant bed was prepared with a hollow cylinder during the reimpantation. The removed augmentation cylinder showed good ossification.

Case 4 (picture gallery)

Missing primary stability