Membrane tears are a significant concern as they may result in postoperative complications such as an oroantral communication as reported recently. In this case, the communication was managed by inserting a fibrin sponge, but it resulted in a cyst-like concavity within grafted bone, which was subsequently managed by re-entry and grafting of the affected site prior to implant placement [14]. As seen in this case, incomplete bone formation can be managed with re-entry procedures, but incomplete bone formation often results in unusual sinus floor morphologies that make conventional sinus approaches difficult. A recent case report describes an unconventional palatal approach for managing sinus floor anatomy complicated by previous sinus grafting [15].

There is still little data on the long-term success of these unconventional re-entry procedures after incomplete bone formation, and here, we present a case with 3-year follow-up after re-entry grafting procedures using either a palatal window or balloon-dilating device for management of previously failed sinus augmentation.