Sinuslift

Sinus lift surgery refers to a special method of oral surgery, the bony floor of the maxillary sinus ( maxillary sinus ) is thickened. The sinus lift is one of several methods for jaw augmentation.

Anatomy

The maxillary sinus is bounded on the inside by the separating bony wall of the nasal cavity to the side out through the wall of the cheek bone and the zygomatic root. Back to top separates a thin bone blanket the large maxillary sinus of the eye socket, the bottom of which it forms. Go down, finally, the so-called sinus floor houses the roots of the small ( premolars ) and large ( molars ) molars. It thus provides the bony separation of the antrum of the oral cavity dar.

After removal ( extraction) of any or all molars can be observed that the thickness of the bone of the sinus floor decreases more or less significantly by the disappearance (atrophy ). The reason for this atrophy is seen in the absence of consistent internal Kaukraftbelastung the bone. But aspects of the diet of these bone layer by the teeth next to play a role. This is to see that the living tooth in a mutual nutrition dynamics is the bone that supports it.

Are all molars removed and replaced on the side of the mouth by a located there, resting on the gums dental prosthesis, the prosthesis causes the chewing pressure on the sinus floor an additional bone loss. After years atrophied in this way gradually the bone layer of the sinus floor very often a thin lamella of sometimes only 1 mm thickness or even less.

Importance for the use of dental implants

Without the sinus lift procedure, a large part of all dental implant procedure in the maxilla when using cylindrical implants could not perform with reliable and acceptable chance of success, because the found bone volume is so low because of the consistently usual late supply that even small and short implants not find sufficient support.

It is obvious that a thin layer of bone is not thick enough to accommodate a cylindrically shaped implant body with sides excess bone. A major part of this implant cylinder would come to stand in the air-filled antrum, while the thin layer of bone to the implant can not give the necessary support. The sinus lift operation has to thicken the goal of the bone layer of the sinus floor, which in the manner described below, the inside of the maxillary sinus membrane is lifted (English: lifting ). This process gave the name of the operation method. It was first launched in the mid 1970s by the American Dental implant dentists and O. Hilt Tatum, published in April 1977 by him and is now considered standard practice in the field of implant surgery in dental implantology.

Surgical Procedure

There are basically four methods for thickening of the bone layer of the sinus:

The problem with all the methods is the initial stability of the implant. Therefore, the height and the hardness of the jaw bone is in the posterior maxillary region, the only criterion for determining whether an implant can be placed during the sinus lift procedure. Can not be guaranteed, the initial stability, then the positioning of the implant should be performed after a healing period of the new bone.

Direct Sinus Lift (after O. Hilt Tatum )

After exposure of the lateral maxillary sinus wall by folding down the gums, the thin lateral maxillary sinus wall is weakened in a 1-2 cm ² large district by a circumferential line with a spherical diamond drill so that they can be pressed like an eggshell. Next then the resulting cover together with the adhesive on the inside of the inner lining of the maxillary sinus ( Schneiderian membrane ) inwards and upwards up (the "lifting " ) so that a more or less large cavity is created. In this cavity then bone chips are often introduced from internal or external bones (beef, pork, human) or synthetic bone substitute material. In the following months or years, this material is biochemically (usually by hydrolysis ) degraded, resorbed and replaced by new bone ingrowth ( "replace resorption ," Axel Wirth man), so that overall a bony thickening of the sinus results. Then thickened in the bone layer and the desired implant is used in a second operation step.

Indirect Sinus Lift

Here, the bore of the cylindrical implant site is up tight promoted to the inner lining of the sinus cavity and then raised with a different instrument mechanically with light hammer blows. Then the well is filled with foreign material or autologous bone - crumbling ( breadcrumbs ), so that the material can spread beneath the inner lining of the maxillary sinus with the introduction of the implant body. This causes the otherwise stationary in the air of the sinus portion of the implant is surrounded by material that then as well as the direct sinus lift is subject to the biochemical degradation mechanisms with simultaneous replacement by natural bone.

This process requires a certain thickness of the layer of the sinus advance (min 4 mm ), while the direct method to well below 1 mm layer thickness is feasible.

Indirect Sinus Lift ( according to R. M. Frey )

With a scalpel, the gum is cut on the upper jaw. The tissue is lifted and exposed the bone. With the help of osteotomes a bone block is mobilized, which is achieved not by the Schneider membrane ( lining of the sinus floor of the antrum ) ( vital bone ). The Schneiderian membrane is raised using this method without being injured with the instruments. In the same operation, a conical implant of pure titanium is inserted. By the conical side walls of the upper jaw bone and the implant will be compressed receives its primary stability. Through the blood - bone chips mixture and the vital bone block, the osseointegration time shortened. Bone replacement materials are not just for use in this method. This procedure can be performed at a residual bone height of the floor of the antrum from 1 mm.

Transkrestale Antro membrano plastids (balloon procedure) (after Benner, Farmer, Heuckmann )

In this method, it is a specially developed technique (that is, with minimal soft tissue damage ) from the bony floor of the maxillary sinus replace the maxillary sinus mucosa by means of a liquid-filled balloon catheter minimally invasive. Here, similar to the indirect sinus lift transkrestal is operated ( by the alveolar ridge ). With a controllable drilling system mm is drilled in the floor of the maxillary sinus to about 1. Then using a special Osteotomes the remaining bone (about 1 mm) is advanced in the direction of the maxillary sinus. The maxillary sinus mucosa remains undamaged. The replacement of such mucosa from the floor of the maxillary sinus is then carried out with a liquid-filled balloon catheter. By controllably filling the balloon, the volume and the release height of the mucosa can be accurately determined. This newly created space is similar stuffed the indirect sinus lift on access through the alveolar ridge with bone grafting material.

This process can be carried out regardless of the amount of the jawbone and is very gentle to the patient.

Cost - benefit analysis

The slightly higher clinical success rate ( implant survival ) of direct sinus lift into perspective when considering the much higher costs compared to indirect sinus lift. From the patient's point of view, the higher invasiveness of direct sinus lift is likely to be an important criterion in addition. However, an indirect sinus lift is promising only with adequate residual bone height of success.

Literature and sources

• Oral Surgery