It is not unusual for the patient to present for a consultation at the oral surgeon’s office and be informed at some point in the discussion that he or she may require a “bone graft” in order to maximize the outcome of dental implant surgery. While this sounds pretty scary at first, the truth is that bone grafting in the oral cavity today is a routine, predictable and painless procedure.
A Brief History of Bone Grafting
As recent ago as the 1970′s and 80′s, before the renaissance of “dental implants”, much of pre-prosthetic oral surgery was aimed at simply building a stable base for a denture in patients who had experienced severe atrophy of their jaws. Many of our readers may identify with this when remembering a mother, father, aunt or uncle who, at an earlier age, had lost his or her teeth and were now wearing dentures. Many may also recall being distracted by those individuals’ dentures while they were either talking or eating. It was kind of like watching someone “rub their stomach and pat their head at the same time.” Aunt Mildred’s jaw and lips might go one way while her teeth were going a different way. While it was unfortunate and often embarrassing, it was certainly not the fault of the denture wearer. The fact is that as we age without teeth the underlying jawbone that supported the teeth atrophies with disuse. The truth is that the only reason our jaws have the amount of the bone that they do is because of the presence of existing teeth and the fact that those teeth are under continuous function. Once teeth are lost for one reason or another, the jaws quickly atrophy to a level of what is called “basal bone”. In cases of a complete loss of teeth, this can leave behind only a narrow hoop of bone in the mandible (lower jaw) or a flat pancake of bone in the maxilla (upper jaw).
Extravagant and often complicated hospital based procedures were devised to address this atrophy and attempt to rebuild the jaws to a point where the patient could comfortably wear a stable denture and have confidence during normal masticatory function. It was not uncommon to use a patient’s ribs to fashion a new hoop in an attempt to increase the vertical size of the lower jaw. Treatment was not only aimed at restoring function but in many cases to prevent a jaw fracture as the strength and size of the jaws were reduced with time. Skin grafts were sometimes harvested from the patient’s thighs to be applied (grafted) intraorally in an effort to prevent the oral musculature from displacing the denture while the person was talking or eating. These more severe methods of preprosthetic surgery are nearly absent from today’s treatment plans. The modernization of dental implants combined with a contemporary preventive approach to bone loss has virtually eliminated the need for such drastic measures.
Bone Grafting for Dental Implants
While the need for bone grafting has been significantly reduced, it has not been eliminated entirely. However, in most cases it is now relegated to small minimally invasive interventions that can be managed quite easily in an ambulatory (office) setting. Furthermore, while bone grafting of earlier years involved harvesting and using large quantities of the patient’s own bone (autogenous grafts), today we can often use processed bone that has been harvested from animals (i.e., cows). These grafts are termed xenografts and are generally comprised only of the mineral content of natural bone, have been sterilized and have had all organic material removed. Using bovine bone (cow bone) as a graft material has become commonplace in most oral surgical offices today and has been a tried and proven technique for many years. A simplified explanation for the success of this form of grafting is that a bovine bone graft is placed to act as a “biological placeholder.” Initially, it mechanically prevents the collapse of the surrounding tissues, whether that is bone or soft tissue. Then, through a process called “guided tissue regeneration,” the human body is fooled biochemically to recognize the graft as natural bone and over time resorbs and replaces it with the patient’s own native bone. Although major autogenous bone grafts are still occasionally required to provide a home for dental implants, the most common bone grafting required involves one or a combination of the following three simpler outpatient procedures:
- The Alveolar Ridge Preservation Graft or “Socket Graft”
- The Autogenous Ramus/Chin Graft or “Block Bone Graft”
- The Subantral Graft or “Sinus Lift Procedure”
When considering dental implants as an option, it is a likely possibility that your surgeon will discuss one or a combination of these grafts with you as a pre-requisite to optimize your treatment plan. Therefore, an explanation ensues below to clarify what each of these grafts is for and how they are typically accomplished.
Information courtesy of AAOMS