If back teeth are to be replaced for being missing for a longer period of time, implants will not find the bony support they need from the maxillary sinus floor. For a successful implant, considerably more bone is required.

To build up this missing bone, the sinus membrane is detached from the bone and elevated, so as to make the space needed for the bone substitute to be inserted. The bone substitute intermingles with the natural bone and creates the space for one or several implants to be inserted.