With the goal to augment the atrophic posterior maxilla, the sinus maxillaris is grafted following elevation of the Schneiderian membrane lining the sinus cavity. Sinus lift is characterized by a high predictability due to its contained morphology. Although successful outcomes with different types of bone grafting materials have been reported, stability of the used material is considered crucial for long-term implant success.
TWO-STAGE LATERAL SINUS LIFT
Access to the sinus cavity is gained by preparing a window at the lateral aspect of the maxillary sinus, preferably with a diamond burr or piezo instrument. Following detachment of the Schneiderian membrane, the created space is filled with a bone grafting material (e.g. cerabone®, maxgraft® or maxresorb®). In order to promote an undisturbed healing, the sinus window may be covered with a collagen membrane (e.g. collprotect® membrane). After a healing time of about six months, the treated site has sufficient bone volume for the placement of one or more implants.
If the residual bone height of the alveolar ridge is sufficient to allow the insertion of the implants without affecting the primary stability, augmentation of the sinus floor and implantation can be performed simultaneously in a one-stage procedure.
INTERNAL SINUS LIFT
Internal, also called crestal sinus floor augmentation is a minimally invasive procedure, similar to that of a normal implant placement. The implant bed is carefully prepared without drilling through the residual bony wall of the sinus cavity. Subsequently, the remaining bone lamella is moved cranially using osteotomes. Hereby, the sinus mucosa is elevated. The resulting space can then be filled with a bone grafting material that is inserted through the osteotomy site.
PROTECTION OF THE SCHNEIDERIAN MEMBRANE
Placement of a collagen fleece (e.g. collafleece®) prior to application of the bone grafting granules protects the Schneiderian membrane from damage. If a small perforation of the Schneiderian membrane is already present, a collagen membrane (e.g. Jason® membrane) may be used to seal the perforation.