In a large majority of people who have had their upper back teeth missing for a long period of time is the increasing downward growth of the maxillary sinus. At birth it is the size of a pea, and progressively grows as the skull matures. This growth is at the expense of the surrounding bone. If you are considering replacing those upper back teeth with fixed teeth that stay in all the time, it may be necessary to perform a sinus elevation procedure to allow room for placement of dental prosthetic implants into this area to support those teeth. This involves placement of bone and/or bone substitutes into an area which was previously occupied by the lower part of the maxillary sinus. Most importantly, this procedure increases the available bone use to place implants and restore the missing back teeth.