Bone is needed to hold either natural or false teeth in place in the mouth. Sometimes the jawbone wears down with use of dentures or loss of natural teeth, which help maintain the bone. Dental surgeons may suggest rebuilding the bone in the mouth when it has worn down so much that it cannot support a dental implant for dentures. The process, called bone grafting, uses replacement bone taken from another part of the body, such as the hip, or created from a mixture of synthetic material and bone from a cow or other animal.
An alternative to this is a sinus lift, which adds height to the upper jaw by filling the sinus cavity with bone. It is done when the back part of the jaw does not have enough bone to hold a dental implant.
In rare cases, a surgeon may move aside a nerve in the lower jaw that gives feeling to the lips and chin in order to increase the amount of jawbone available for implants. The technique involves drilling a hole in the lower jawbone to move the nerve aside, but it is not done often because it can damage the nerve.
Another procedure, called distraction, cuts and separates part of the bone from the jaw in order to give it more height. The bone is then held apart from the rest of the jaw with a metal device held in place by pins or screws. The jawbone gets taller over time as the device is unscrewed slightly each day and the bone grows to fill in the spaces between the separated pieces of bone.