Is bone grafting the same as sinus lifting?

In dentistry, bone grafting refers to the rebuilding of lost bone. When our adult tooth grows and develops it brings a certain amount of bone with it to support it in the jaw. Technically, we call this bone alveolar bone. The maximum amount of supporting bone is present when the tooth is completely erupted (in its final position) and the root of the tooth is fully formed. As time goes on and if an infection develops around a tooth (typically from periodontal disease, root end abscess, or tooth decay), the tooth is often extracted. 

Once a tooth is lost (for any reason), the bone that developed with that tooth is resorbed (removed) by the body. There is now a void or defect left by the missing tooth. This defect can many times be corrected by rebuilding the lost bone in the jaw with either your own bone taken from another area, or a bone substitute. When bone is grafted in the sinus, the membrane that lines the sinus must first be gently pushed up to make room for the bone graft, thus the name sinus lifting.

When the upper back teeth are lost, the bone that supports those teeth is also lost, allowing the sinus to expand. The expansion of the sinus (now that the sinus is not contained by teeth) also  causes a resorption of bone. The result of this resorption is that a thin shelf of bone remains. In order to regain the bone lost in the upper molar area, an opening must be made in the sinus membrane. The membrane must be lifted (pushed) upward and sideways creating a space where bone can be grafted, thereby regaining the lost alveolar bone. Once the grafted bone matures, usually in around six months, the procedure of placing a dental implant in the newly formed bone can begin.