There are times when composite materials can simply not provide sufficient bulk or adequately replace the amount of bone that is missing after tooth loss. In these cases, it is sometimes necessary to revert to harvesting the patient’s native bone to assist in a “live bone” replacement of the deficient area. The most commonly used grafting procedure is “an autogenous graft” (harvested from the patient) and is placed in the form of a block. Hence, we have derived the terminology “autogenous block bone graft.” More often than not the block of bone is obtained from the lower jaw in the region where the wisdom teeth used to reside. An alternate site used commonly to obtain a block of bone is the chin.
When is it needed?
There are several possible causes of bone loss that produce large bone to warrant the need for this approach. A few of the most common causes include:
- Areas where teeth were removed and not replaced
- An area where a tooth is missing and the nature of the disease associated with the tooth caused extensive bone destruction (i.e., infection, cysts, tumors).
- Areas of the jaw where permanent teeth were congenitally missing and as a result, normal tooth supporting bone failed to develop.
- Bone lost from dental trauma.
What does the procedure involve?
The procedure involves removing a small block of bone (approx. 1 cm square) from either of the two aforementioned sites and transferring that bone to the area of bone deficiency. The graft is then secured with one or two tiny screws and overlaid with particulate bone and a collagen membrane. The surgical site is securely closed and six months is usually given for the graft to fuse to the underlying jawbone before returning to the area to place an implant. Once the graft is mature, the grafted bone will not only house an implant in “live” bone but it will also act to support the gum architecture in a manner that is both cosmetically pleasing and hygienically easy to maintain. Bone grafting in the mouth today is a routine, predictable and painless procedure. It is done as a separate procedure before the implant is placed.