Sinus membrane elevation and simultaneous insertion of dental implants: a new surgical technique in maxillary sinus floor augmentation.

Endosseous implants are frequently used for prosthetic reconstruction in the edentulous patient. Sufficient volume and density of the alveolar bone for implant integration and load bearing are prerequisites for good clinical outcome. Bone resorption following the extraction of posterior maxillary teeth sometimes results in severe loss of bone in vertical and ⁄ or horizontal dimensions, which may compromise the use of dental implants. Various grafting procedures have been used to establish an adequate bone volume for the placement of endosseous implants in atrophic posterior maxillae. The most common technique is augmentation of the maxillary sinus floor, a technique introduced by Tatum (28) and modified by Boyne & James (2) and Wood & Moore (34). Access to the maxillary sinus is obtained by drilling a bone window in the lateral sinus wall using a small round bur, while ensuring that the sinus membrane remains intact. The sinus membrane is then carefully elevated, mobilized together with the attached bone window and rotated medially. Maxillary sinus elevation surgery is usually performed in conjunction with a variety of bone grafting material, including autogenous bone from the iliac crest (1, 21), the mandibular chin (16, 19, 22, 34), the mandibular ramus (3) or the calvarium (31), as well as bone substitutes used alone (8, 10) or in combination with autogenous bone (18, 24, 32, 35). Summers (26) described an alternative surgical technique to increase the available bone volume in the posterior maxilla. Access to the maxillary sinus floor was achieved through the alveolar ridge, using various instruments to form and shape a socket. The sinus membrane was subsequently elevated and a bone graft was placed prior to the immediate insertion of a titanium implant. Even if new bone can be obtained after placing bone grafts in the maxillary sinus, it might not be a prerequisite for bone formation per se. The mere lifting of the sinus membrane and the establishment of a void space with a blood clot may yield new bone, following the principles of guided tissue regeneration (4). This concept was supported by a study in which bone formation was detected at the apical part of implants protruding into the sinus cavity (5). Spontaneous bone formation at the floor of the maxillary sinus has also been observed 3 months following the removal of an intrasinusal cyst (14). The present article presents the development and the clinical and histological evaluation of a new clinical technique for maxillary floor augmentation, which does not include bone grafting.