A dental bone graft is a procedure used to rebuild or augment jawbone volume lost due to trauma, periodontal disease, or tooth extraction. Bone loss compromises the stability required for successful dental implant placement or leads to changes in facial aesthetics. The graft material acts as a temporary framework, signaling the body to grow new, healthy bone tissue. These materials come from various sources, each offering different biological properties to encourage regeneration.
Bone Harvested from the Patient
Bone harvested from the patient’s own body, known as an autogenous graft, is considered the most effective material for reconstruction. It is the only type that contains living bone cells (osteoblasts), giving it true osteogenic capabilities. The autograft also possesses osteoinductive properties, meaning it has growth factors that actively signal stem cells to differentiate into bone-forming cells, in addition to acting as a passive scaffold (osteoconductive).
Using the patient’s own tissue eliminates the risk of immune rejection or disease transmission, contributing to its high success rate. The material is typically harvested from intraoral sites, such as the chin or the back part of the lower jaw. For larger defects, the surgeon may take bone from extraoral sites, including the hip or the tibia. Harvesting the bone requires a second surgical site, which is the main drawback, increasing patient discomfort and overall recovery time.
Bone from Human Donors
Allogeneic grafts (allografts) are bone materials sourced from deceased human donors through accredited tissue banks. This material is processed to be safe and sterile, eliminating the need for the patient to undergo a second surgery for bone harvesting. The bone is typically freeze-dried and sterilized to remove all potentially harmful components, including cellular matter and viruses.
Allografts are classified into two main forms: Freeze-Dried Bone Allograft (FDBA) and Demineralized Freeze-Dried Bone Allograft (DFDBA). FDBA primarily acts as an osteoconductive scaffold because its mineral content is intact. DFDBA undergoes an acid-wash process that removes mineral content, exposing growth factors trapped within the bone matrix. This demineralization grants DFDBA osteoinductive properties, allowing it to actively signal for new bone formation.
Materials Derived from Animal Sources
Graft materials derived from animal sources are known as xenogeneic grafts (xenografts), most often sourced from bovine (cow) bone. These materials are preferred for their abundant supply and structural similarity to human bone mineral. The animal bone undergoes an extensive purification process, typically involving high heat treatment, to remove all organic components that could cause an immune reaction.
The final product is a pure mineral matrix composed primarily of hydroxyapatite, the mineral that gives human bone its rigidity. Because all cellular and protein components are removed, xenografts are not osteogenic or osteoinductive. Instead, they function purely as a durable scaffold (osteoconduction), providing a stable structure for the patient’s own bone cells to deposit new bone. These scaffolds maintain the volume of the defect space while the body completes integration and replacement.
Synthetic and Man-Made Options
Alloplastic grafts are lab-created, synthetic materials designed to mimic the structure and function of natural bone. These options offer the advantages of guaranteed sterility and an unlimited supply, avoiding concerns related to human or animal tissue sourcing. The most common materials are calcium phosphate compounds, such as beta-tricalcium phosphate (B-TCP) and synthetic hydroxyapatite.
Bioactive glasses, which are specialized ceramics, are another type of alloplastic material. These materials react with bodily fluids to form a layer that strongly bonds with the surrounding bone. Alloplastic materials are primarily osteoconductive, functioning solely as a passive scaffold for new bone growth. The rate at which the material is resorbed and replaced by new bone can be chemically controlled, making them a predictable option for smaller defects.
Factors Influencing Material Choice
The selection of a specific bone graft material is a clinical decision based on patient and defect-specific factors. The size and shape of the bone defect are primary considerations; large defects often require the volume-maintaining properties of xenografts or the regenerative power of autografts. The location also plays a role, as areas needing high structural integrity for immediate implant placement may benefit from materials that resorb more slowly.
The required rate of healing is another factor; materials with osteoinductive properties, like DFDBA or autografts, are preferred when faster bone formation is desired. The patient’s overall health status and any underlying conditions that could affect healing must also be considered. Practical aspects, such as the patient’s willingness to undergo a second surgical procedure or cost considerations, also influence the final choice.