Bone grafting is an important everyday treatment to help replace a dental patient’s missing teeth, facilitate bone formation, and promote wound healing. For a patient, the prospect of a bone graft can be look at as daunting news. The truth is, a bone graft is a routine, predictable, and usually painless procedure, especially if you have the right materials.
Today there are an overwhelming array of bone graft material options. How do you choose which bone graft material to use? Does your dental supply company offer the best possible solutions? It’s important to know the difference between the various materials available, and select the one that best fits your patient’s needs.
In this article we are going to discuss the different bone graft material types and the benefits they provide so you can determine which is best for certain procedures.
Ideal Bone Graft Requirements
There are four major factors for a bone graft to be successful:
- There must be osteoblasts present to create new bone. If there is not enough osteoblasts the bone graft will fail.
- There must be a sufficient blood supply available for nourishment. Blood is crucial for cell viability and clot formation. A blood clot acts as the initial matrix where cells migrate and serves as an anchor for osteoblasts.
- Graft stabilization is vital to the healing process. Movement and mechanical stresses can lead to a disruption in the blood clot. Fibrous tissue could fill the area instead of bone. Fixation tools such as titanium mesh, collagen membranes, bone pins and screws may be used to help steady the area.
- There must be no tension on the soft tissue. Guided bone regeneration (GBR) is based on the separation of the grafted site from the surrounding soft tissue. Since bone is the slowest growing material, it is important to use GBR to keep the faster growing tissues such as epithelium, fibrous tissue or gingival connective tissue out of the defect to allow the formation or vital bone.
There are three biological mechanisms that helps form and heal new bone after a bone graft has taken place. This is done through osteogenesis, osteoinduction and osteoconduction
- Osteoconductive bone graft material acts as a scaffold for new bone growth that is perpetuated by the native bone. This allows osteoblasts from the wound margin to infiltrate the defect and to migrate across the graft, spreading and generating new bone. A bone graft material should at least be osteoconductive.
- Osteoinductive materials stimulate primitive mesenchymal cells brought in through the blood supply from adjacent bone or periosteum. They involve the stimulation of osteoprogenitor cells to differentiate into osteoblasts that start new bone formation.
- Osteogenic graft materials supply actual viable osteoblasts themselves and contributes to new bone growth along with bone growth produced by the other two mechanisms.
Classification of Bone Grafts
Autograft (autogenous graft)
Ideally, an autograft is the best type of bone substitute since it is taken from the patient’s own bone. The bone is transferred from one location to another within the same individual. An autograft is ideal because there is no risk of disease transmission. Autograft is also considered osteoinductive and osteogenic, as well as osteoconductive.
However, because you are adding an additional surgical site to the patient, there is an increased risk of pain, infection, scarring, donor site morbidity, complexity in the surgical procedure, and a limited bone supply.
Autograft Bone Graft Material
If your patient requires an autograft, in oral and maxillofacial surgery, bone is taken from the chin area (mandibular symphysis) or anterior mandibular ramus. An autograft can also be performed without a solid bony structure using bone taken from the anterior superior iliac spine. It can be harvested as bone blocks or milled to generate particles.
Similar to the autograft bone, allograft is taken from humans. It has a natural bone composition and structure. The difference being that the bones are sourced from an individual other than the one that needs the bone graft.The bone tissue is osteoinductive and osteoconductive but does not contain osteogenic properties. Allograft bones are usually sourced from a bone bank where the bone has been donated by cadavers. There is a controversy over the possible transmission of infectious diseases such as HIV, hepatitis B and C.
Bone graft material for allografts are available in different forms from mineralized/demineralized bone granules to whole bone segments. They can be cortical, cancellous, or both.
Allograft Bone Graft Material
Allograft bone granules provide a foundation for encouraging cellular growth and helps in the rapid bone regeneration by allowing for faster remodeling. Bone granules are utilized in socket preservation for future implant placement, ridge reconstruction for prosthetic therapy, filling osseous defects and maxillary sinus floor elevation.
Allograft bone segment blocks are a predictable and effective alternative to traditional autogenous block grafting and ridge augmentation. Instrumental in bone volume regeneration for severe bone atrophy cases that require an increase in initial stability for an implant site.
When looking for bone allograft dental suppliers, it is important to make sure they are fully accredited member of The American Association of Tissue Banks and FDA registered. We also recommend finding out where the dental supplies are being shipped from to ensure there is no risk of safety or storage concerns.
Xenograft material originates from non human resources such as bovine and porcine. Non vital bone from cows or pigs is demineralized and deproteinized to expel the risk of disease transmission and allergic reaction. By removing all of the protein, it becomes it a natural bone structure very similar to human bone.
Xenograft provides long term volume stability but is osteoconductive only.
Xenograft Bone Graft Material
While Xenograft materials are available in both particulate and segmented bone block form, it has been found that bone blocks from Xenograft used in vertical augmentation lack strength and can break during the screw fixation process. However, bovine-derived bone grafts (particulate and blocks) have successfully been used for the treatment of human intrabony defects and ridge augmentation.
Bovine: Particle anorganic cancellous bone graft granules are naturally sourced from bovine bone material. This type of bone graft material allows for a combination of a porous structure for vascular access with a roughened surface that is favorable to cell adhesion and subsequent bone matrix deposition.
Porcine: Particle porcine Xenograft particulates are porous, anorganic bone mineral with a carbonate apatite structure derived from porcine cancellous bone. Interconnecting macroscopic and microscopic porous structure supports the formation and ingrowth of new bone.
Alloplast bone graft material is synthetic in nature and used to reduce the risk of disease transmission. Alloplasts are usually made from calcium phosphate based ceramics such as hydroxyapatite, a naturally occurring mineral that is also the main mineral component in bone. Hydroxyapatite (HA) is successful due to its osteoconduction and the acceptability by bone. An added advantage of synthetic materials is their abundance in comparison to natural materials. Alloplasts have been successfully used in periodontal reconstructive surgery.
Alloplast Bone Graft Material
Alloplasts are manufactured in a variety of forms and with varying properties. They can be made available in both resorbable and nonresorbable forms as well as various levels of porosity and size. The most common alloplastic materials are tricalcium phosphates, bioactive glasses, and HA and dicalcium phosphates.
Tricalcium phosphates (TCP) is a porous form of calcium phosphate. It is most commonly used as a partially resorbable filler that allows for bone formation and replacement. It has two crystallographic forms, α-TCP and β-TCP and is bioactive and resorbable.
Hydroxyapatite (HA) is non-osteogenic, not conclusively osteoinductive, but rather works as an osteophilic and osteoconductive graft material. It has been marketed for use in a variety of forms: non-resorbable, solid nonresorbable, and resorbable (non-ceramic, porous). The temperature at which HA is processed dictates its resorptive potential.
*Many materials will use both HA and TCP as a synthetic mix matrix. The purpose of using HA and TCP in combination is a balance between the stable HA which can be found years after implantation, and the fast resorbing TCP. The ratio between the two affects the resorptive properties of the bone graft material.
Bioactive glass is composed of silicon dioxide (45%), calcium oxide (24.5%), sodium oxide (24.5%), and phosphorus pentoxide (6%). Studies have reported that bioactive glass as superior manageability, homeostatic, and osteoconductive properties. However, bioglass does not undergo resorption so bone forms around the particles and grows via osteoconduction. When mixed with autogenous bone graft material, it doubles natural bone regeneration.
Aside from costs and weighing your options, when choosing your dental supplies, you should consider where they are coming from and how they are being stored. Ensure a dental supplier’s materials are FDA registered and the quality of their product is guaranteed. At Predictable Surgical Technologies, we guarantee our products meet the highest health and safety standards that you and your patients deserve.
Proper bone grafts materials are vital to the success and health of your patient. Knowing what your options are and being equipped with the best bone graft materials provides the confidence and tools for maintaining a reputable practice.