Transantral Grafting (Sinus Lift)
After tooth loss, alveolar resorption occurs. In the posterior -rnaxilla, crestal bone resorption Js also accompanied by sinus pneumatization. In situations wHere inadequate bone existsto place implants of appropriatelength, sinus floor.augmentation can be performed. Thi, can be dcne-indirectly 0through the implant osteotomy site or directly-by an approach through the lateral wall of the maxillary sinus. ‘ hen only a few millijneters of augmentation is needed
in copjunction with simultaneous impla.,ot placement, indirect sinus lift is effective. This procedure relies on the lack of density found in maxillary cancellous bone. The initial drill-is used to locate the angulation and position of the planned implant. The depth is drilled just short of the sinus floor. Osteotoines are then used to progressively enlarge the site. The osteotome is cupped on the end and compresses the walls of the osteotomy site: it alsoscrapes bone from the sides of the wall, pushing it ahead. The bone· of the sinus floor is pushed.upward elevating the’ sinus rrterribrane and depositing the bone from the .lateral wall of the osteotomy into the sinus below the membrane (Fig. 14-63). If needed, additional graft material
can be introduc ed through the implant site. Undetected’ per oration may occur with this tech- ‘niqiie. :rhi’s procedure is only possible when a few mil- Iimeters of bone’ is needed for an implant that has ade, quate primary stability in native bone. . If several implants are to be placed or more than
2 or 3 mm of augmentatio is needed, a direct approach is required .. A window is created In-the lateral wa11 of the sinus, and the sinus membrane is elevated and the floor is grafted to increase vertical bone height (Fig. 14-64). Implants may be placed simultaneously With the grafting procedure if adequate native bone is present Jor primary implant stability. This is usually defined a.s4 mm or more of bone. If less than 4.nun of bone Isavailable.jhe procedure should be staged with initial grafting alone, after
. which the graft Is.consolidated and the implant- placed .. Transaritral grafting (i.e., sinus lift) procedures can be .per- . formed in an outpatient setting using autogenous bone,allogeneic bone, or bone substitutes.
Success is similar for all these materials. Autogenous .bone requires less time than allogeneic or xenogeneic bone to consolidate (4 to 6 months versus 7 to 12 months). The available bone to support the implant can be significantly improved with these techniques. Patients who smoke have a significant increased failure rate. Some authors suggest that smoking [s a contraindication to sinus lift. In addition, a much higher. incidence of infection after this pr-ocedure is found. than with other implant surgery. Antiblotlc prophylaxis is paramount. . Patientsmust also refrain ‘from wearing prosthesis. over the surgical area for a week.