Mini maxillary sinus elevation using Sincrest

Mini maxillary sinus elevation using Sincrest

 

 ITALIAN VERSION

 

MINIMALLY INVASIVE TRANSCRESTAL MAXILLARY SINUS ELEVATION

 

Inserting implants in the back of the maxilla can present considerable technical difficulties. The dentist has often to face coronally-apically reduced bone portions deriving from crestal bone reabsorption or maxillary sinus pneumatisation, especially when in the area there are extractions performed many years before.

In the case the reduced height is mainly due to crestal bone reabsorbtion, before inserting the implants it is necessary to coronally regenerate the bone. This is done in order to avoid using prosthesis with teeth which are too long and would cause an unfavourable crown/root ratio.

On the other hand, when the reabsorption is mainly due to a pneumatisation of the maxillary sinus, it is important to estimate the amount of remaining bone.

As a matter of fact, if the bone height is < 4mm, there is enough bone to achieve primary stabilization of the implant; in this case the operation will be carried out in a single stage performing a mini-elevation of the maxillary sinus and, at the same time, inserting the fixture.

The maxillary sinus mini elevation technique with osteotomes, explained by Summers in 1994, requires the implant site to be prepared up to 2 mm from the sinus floor. At this point, using a concave osteotome, it is time to break the 2 remaining mm of bone; the bio-material is then inserted with the help of the osteotomes, leading to the elevation of the Schneider membrane. In this technique it is the load of the bio-material that elevates the sinus floor: the osteotomes are never to enter in the maxillary sinus.

Once the sinus floor has been elevated, it is time to insert the implant. The mini-elevation technique, when usable, provides remarkable benefits in respect to the standard elevation of the sinus floor.

With this technique, it is indeed necessary for the patient to undergo just one operation, the morbility is considerably lower than in the standard elevation, vascular complications are noticeably reduced and prosthetic rehabilitation times are appreciably shortened.

One disadvantage of this technique is that the surgeon operates blindfold, without seeing directly: this greatly increases the risk of tearing Schneider membrane – sometimes being just a few tenths of millimeter thick.

In this work we will analyze a new device, made by Meta, that should make it possible to elevate the sinus floor in a safer and more controlled way.

The Sincrest is a transcrestal maxillary sinus floor elevation kit made up of burs for electric handpiece, depth stops of various heights and a manual osteotome. The manual osteotome was designed to achieve the controlled fracture of the sinus floor by the maxillary sinus mucosa without damaging it.

The patient, aged 64, non smoker, came to our observation complaining about a low chewing efficiency after the maxillary sixths were extracted many years before and not replaced with a prosthesis. The X-rays show a bone with reduced height because of the pneumatisation of the maxillary sinus.

From endo-oral X-rays made using Rinn Digital Sensor Positioning Aids and a CAT, the residual height is estimated to be less than 8 mm. It is thus decided to insert the implant and at the same time elevate transcrestally the sinus floor using the SinCrest device.

Sinus lift SinCrest

Sincrest

SinCrest sinus
SinCrest maxillary sinus
Sincrest maxillary sinus lift

The crest is cut with a size 15 Bard Parker scalpel and a full thickness flap is made performing a double widening suture both buccally and palatally.

5b

Sincrest Meta

Meta

Sincrest kit

Sincrest drill

The first bur to be used is the Locator Drill, that works only for 3.5 mm and only drills the cortical bone.

Sincrest tips

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Subsequently we will use the 1.2 mm diameter Probe Drill. In order to take the burs from the kit without touching them with the hands, Meta provides a tool called Drill Gripper. The Probe Drill bur, flat headed, is sharp only on the head; for this reason it is not possible to apply a lateral cutting force and correct the direction of the implant hole.

The depth of the work must be planned at about 2 mm from the maxillary sinus floor by means of endo-oral X-rays. In this case, since the distance between the crest and the floor is of about 8 mm, a 6 mm stop is inserted.

Meta tip

Meta sinus

Meta sinus lift

Meta maxillary sinus

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At this stage it becomes necessary to make endo-oral X-rays using the 1.2 mm RX Pin to check the correct distance from the maxillary sinus.

Meta maxillary sinus lift

After the X-ray check it is possible to go down to a 6 mm depth.

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Meta maxillary sinus mini-lift

After checking that distance, the 3 mm diameter Guide Drill will be used. That bur only works for a depth of 2 mm and allows for the correct centring of the following bur.

Meta sinus elevation

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As a matter of fact, once the stop at 6 mm is inserted, the 3 mm diameter SinCrest Drill will be used: this will create a precise housing to insert the 3 mm SinCrest tool.

Meta minilift

Sinus minilift Sinus minilift 2
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Maxillary minilift

Sincrest minilift

In the following video it is shown how the SinCrest device works.

VIDEO

At this stage, the device is manually screwed until one can see the white stripe on the probe. Seeing that stripe means that the SinCrest has reached the depth made by the burs.

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Sincrest lift

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Sincrest sinus 2

The handpiece is now rotated of ½ rotation first counterclockwise and then clockwise applying a pressure axially. By repeating this “screw and unscrew” motion, the thread of the device is kept completely stationary and an osteotomy of 0.5 mm is carried out apically. At this stage it is possible to screw the SinCrest again so that it will go forward of 0.5 mm apically.

It is always necessary to check the residual resistance of the sinus floor by applying a light pressure on the probe. If the probe does not go further, it is necessary to repeat the forward movement sequence of the device.

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When the white stripe disappears, it means that the bone operculum is fractured and it is possible to insert the bio-material for the elevation.

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Sincrest Meta sinus
In the following video it is shown how the SinCrest device clinically works.

VIDEO

In this case we used Bio-Oss inserted in the sinus by means of a carrier and pushed apically using osteotomes: it is important not to go further than 8 mm. Finally the Strauman male threader is screwed in order to make a hole of 3.5 mm diameter: this is needed to insert a 10 mm long Straumann implant with a 4.1 mm diameter SLActive surface sunk for 1.5 mm due to aesthetic reasons.

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Bone Sincrest

Bone sinus lift

Bone sinus minilift

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Implant sinus lift
Implant sinus

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After inserting a healing abutment with a height of 2 mm, a detached stitches suture using ePTFE (Tevdek 4.0) coated interweaved polyester was made.

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Implant sinus minilift
Implant maxillary sinus minilift

Straumann sinus lift

Straumann sinus minilift

In conclusion, SinCrest has proved to be a really effective device that makes it possible to elevate the Schneider membrane in an extremely safe way even by the non-expert.

Its limit is that it cannot be used when the vertical distance from the maxillary sinus floor to the occlusal floor of the tooth adjacent to the site of operation is more than 23 mm and when there is a type 4 bone, as it would determine a reduced stability while screwing the SinCrest device.

The authors of the present article also believe this device should not be used when dealing with very inclined sinus floors since, in these cases, the blade could damage the sinus membrane.

Another limitation of the kit is to be found in the succession of the burs. The gap between the first (1.2 mm) and the second (3 mm) when preparing the implant site is of 1.8 mm. This big gap can cause overheating of the bone and, above all, does not allow to correct the direction of the implant hole. This issue may be compensated using burs from one’s own implant kit.

Bibliography

1: Summers RB.
A new concept in maxillary implant surgery: the osteotome technique.
Compendium. 1994 Feb;15(2):152, 154-6, 158 passim; quiz 162.

2: Summers RB.
The osteotome technique: Part 2–The ridge expansion osteotomy (REO) procedure.
Compendium. 1994 Apr;15(4):422, 424, 426, passim; quiz 436.

3: Summers RB.
The osteotome technique: Part 3–Less invasive methods of elevating the sinus
floor.
Compendium. 1994 Jun;15(6):698, 700, 702-4 passim; quiz 710.

4: Summers RB.
The osteotome technique: Part 4–Future site development.
Compend Contin Educ Dent. 1995 Nov;16(11):1080, 1092 passim; quiz 1099.

5: Summers RB.
A new concept in maxillary implant surgery: the osteotome technique.
Compendium. 1994 Feb;15(2):152, 154-6, 158 passim; quiz 162.

6: Summers RB.
Sinus floor elevation with osteotomes.
J Esthet Dent. 1998;10(3):164-71.

7: Brägger U, Gerber C, Joss A, Haenni S, Meier A, Hashorva E, Lang NP.
Patterns of tissue remodeling after placement of ITI dental implants using an
osteotome technique: a longitudinal radiographic case cohort study.
Clin Oral Implants Res. 2004 Apr;15(2):158-66.

8: Woo I, Le BT.
Maxillary sinus floor elevation: review of anatomy and two techniques.
Implant Dent. 2004 Mar;13(1):28-32.

9: Diserens V, Mericske E, Schäppi P, Mericske-Stern R.
Transcrestal sinus floor elevation: report of a case series.
Int J Periodontics Restorative Dent. 2006 Apr;26(2):151-9.

10: Draenert GF, Eisenmenger W.
A new technique for the transcrestal sinus floor elevation and alveolar ridge
augmentation with press-fit bone cylinders: a technical note.
J Craniomaxillofac Surg. 2007 Jun-Jul;35(4-5):201-6. Epub 2007 Jun 20.

For information:

zerodonto@gmail.com

tel. 0039 081 2451805

Mini maxillary sinus elevation using Sincrest ultima modifica: 2009-05-14T00:21:00+00:00 da Fabio Cozzolino

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