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Procedures

Bone grafting

Procedure overview

Learn about the dental procedure, when it is generally prescribed, and other information which can increase your knowledge of the topic.

Alternate terms: Osseous grafting.

When teeth are lost, the "alveolar" bone that previously housed them begins to dissolve away in a process called "resorption." Depending on the rate of resorption, the remaining bone may be insufficient to replace the missing tooth with an implant. If the missing tooth is to be replaced with a fixed bridge, the prosthetic tooth ("pontic") may look artificially large if the bone and gum tissue ("gingiva") have resorbed significantly.

View animation Bone Resorption

Bone resorption and gingival recession on neighboring teeth are common occurrences following extraction of a tooth.

Figure 1: When a tooth is lost, the bone typically resorbs, producing a depression at the site of the missing tooth. Note the resulting gingival recession and exposed tooth root on the molar.

One solution to this dilemma is to "graft" new bone onto the site. This process is sometimes referred to as "site development", which refers to the fact that proper bony and gingival contours need to be re-established before ideal tooth replacement can be done. There are several ways of doing this. First, the bone resorption can be minimized by packing the tooth socket with powdered bone graft material at the time of tooth removal.

Sterilized, freeze-dried bone graft particles

Figure 2: Sterilized bone powder.

Placing powdered bone graft material into a fresh tooth extraction site is known as a "socket graft", and is intended to prevent resorption, not rebuild the site after resorption has taken place. Socket grafts are sometimes referred to as "ridge preservation".

The second method of grafting a bone resorption defect is to place the graft material in the site after the resorption has taken place. Depending on the length of time that has elapsed since the teeth were lost, and the size of the resorption defect, your dentist may or may not be able to use powdered bone graft materials to regenerate the lost bone. Sometimes it becomes necessary to use whole blocks of bone, which are held in place by fixation screws while the body "integrates" the graft. Bone powder may be used as a filleting material around the abrupt edges of a block graft. Blocks can either be harvested from the patient at the time of the graft (known as an "autograft"), or may be obtained from a tissue bank that supplies human block cortical bone ("allograft").

Bone grafting is prescribed to prevent the loss of tooth supporting ("alveolar") bone following tooth removal, and to re-establish the height (limited) and width of alveolar bone that has already been lost. This is especially important if a patient's restorative treatment plan includes fixed bridgework, or dental implants.

View animation Bone Resorption

Severe bone loss at a lower molar tooth extraction site may complicate replacement of the tooth.

Figure 3: Severe bone loss at the site of a missing lower molar tooth has led to a situation in which ideal placement of a dental implant would be significantly compromised.