For historical and biologic reasons, autogenous bone has long been considered the “gold standard” among graft materials. Autogenous bone is the only graft material that is osteogenic and fulfills all three components of the regeneration triad. In the mid-1970s, Brånemark began using autogenous bone grafts with dental implants in the treatment of the atrophic edentulous jaws. However, the use of machined implants often placed simultaneously with the graft and a steep learning curve led to poor implant survival rates. Over the years, the use of intraoral donor sites has become preferred when possible to decrease the complexity and risks of bone grafting. Block bone grafts can be combined with particulate bone and guided bone regeneration techniques to enhance peripheral volume gains.
Autogenous bone grafting has several advantages over other augmentation techniques including short healing times, favorable bone quality, lower material costs, no risk of disease transmission or antigenicity, and predictability in the repair of larger defects or greater atrophy. Denser cortical bone grafts exhibit minimal resorption on incorporation, making them ideal for site development.
The obvious disadvantage of using autograft is the morbidity from bone harvest. However, approaches to minimize morbidity have been addressed including the use of preemptive analgesia, long-acting anesthesia, and harvesting techniques such as piezoelectric surgery. There are also donor sites associated with a lower incidence of complications (proximal tibia and mandibular ramus) that can be procured in the office setting. In the treatment of more demanding reconstructions, the benefits of autograft often outweigh the risks of complications. Iliac bone grafts are reserved for the reconstruction of larger defects and severe atrophy.
My observations have been that many clinicians have become too quick to abandon traditional well-established approaches for easier, faster, and less-complicated procedures that may not provide comparable results. It is frustrating to inherit a case where grafting was attempted using bone substitutes when autogenous bone would have been the preferred choice. Sometimes clinicians argue, “the patient did not want a hip or chin graft.” I have met few patients who actually wanted to have bone harvested from their body. It has been said, “if you want an omelet, you have to break some eggs.” Well, sometimes if you want to reconstruct a ridge, you have to harvest bone.
Improvements in implant designs have reduced the need for bone augmentation in many cases. Studies have found autogenous bone may not be needed routinely in the management of localized bone defects and sinus bone grafting. However, the use of autogenous bone continues to be an invaluable technique in the management of more difficult augmentation cases. It is unlikely that existing bone substitutes (allografts, xenografts, and alloplasts) will ever challenge the gold standard. However, growth factors may improve their biologic activity and improve results. Stem cells, signaling molecules, and new scaffolds are areas of intense research in regenerative medicine. Future advancements in tissue engineering will likely produce alternatives to autogenous bone grafts that may well exceed existing clinical outcomes and replace traditional indications for its use. Until then, we should continue to use well-researched techniques that provide predictable outcomes in various clinical situations.
Craig M. Misch, DDS, MDS
Member, Editorial Board, IMPLANT DENTISTRY