Crestal Sinus Lift With Osseodensification in Severely Atrophic Maxilla: Case Series With Long-Term Follow-up

In the posterior maxilla, bone volume, height, and density are often insufficient for implant placement and rehabilitation, which can affect implant long-term stability and success. These anatomical limitations may dictate the need for sinus grafting procedures. Osseodensification is an implant site instrumentation method that enhances bone density and can also be used for transcrestal maxillary sinus augmentation. This technique utilizes bone plasticity through specially designed burs that compact and densify bone along the osteotomy walls while simultaneously propelling bone particles laterally and apically. This process generates a hydrodynamic compaction wave at the bur tip, which propels irrigation fluid into the sinus cavity lifting the membrane and simultaneously compacting bone particles grafting the sinus with autogenous bone. Additionally, the flutes of the osseodensification bur permit the operator to subsequently graft biomaterial, facilitating further elevation of the Schneiderian membrane. Current literature outlines three specific protocols for sinus floor elevation and implant placement utilizing osseodensification with residual bone height (RBH) requirements: ≥6 mm for protocol I, ≥4-5 mm for protocol II, or ≥2-3 mm for protocol III, with concurrent implant placement in the presence of adequate bone and soft-tissue volume. Osseodensification-mediated sinus grafting allows for shorter surgery duration, reduced postoperative edema, less reported pain, and subsequently decreased analgesic intake compared to lateral window techniques. This article details the step-by-step osseodensification sinus lift protocol IV, a two-stage sinus floor elevation indicated in cases of RBH ≤0.5-1.5 mm as an alternative to lateral window techniques.