Dental implants require a certain volume of bone to “live” in. Bone grafting is a general term we use to describe procedures which either help maintain the bone volume present (site preservation), or add bone to an area which has become deficient (due to the normal resorption process which occurs in the body when a tooth has been removed).
Site Preservation
When a tooth is removed, the body sees no reason to continue to maintain the bone that formerly housed the tooth. As a result, this bone will begin to resorb and usually continues over time. Placement of bone grafting materials at the time of extraction will provide the body with a “scaffold” to create its own bone in the remaining socket as it heals, and will preserve the bone volume to allow placement of an implant. This bone is ideal for implant placement 4-6 months after the grafting procedure. When an implant is placed, the body will continue to maintain this bone as it did when a tooth was there. If no implant is placed, even after grafting, the body will eventually resorb the bone. Site preservation is very often in tandem with an extraction, when eventual restoration with an implant is planned, as it is painless, reasonably inexpensive, and often eliminates the need for further grafting procedures.
Bone Grafting to Expand Bone Width
If a tooth has been missing for quite some time, there often is not enough bone volume for the tooth to “live” in. In this case, bones need to be added and healed (usually 6-9 months) prior to an implant being placed. Sometimes a “borderline” amount of bone exists such that the implant can be placed, but requires the addition of a small amount of bone on the outside.
Bone Grafting near the Sinus Cavity
A sinus cavity (airspace) exists on both sides of the upper jaw near the root tips of the molar and premolar teeth. Depending on the exact location of this cavity relative to the mouth, determines how much bone is available. After tooth have been extracted, the sinus cavity will often expand and cause further resorption of the bone, to the point where not enough bone is available to place a dental implant of sufficient length. In this case, as grafting procedure is performed to increase the bone volume in this area to allow successful placement and healing of an implant. If only a small amount of grafting is needed, this can usually be done at the same time as the implant is placed. If a larger graft is needed, a separate procedure may be necessary.