A bone graft is a procedure where bone is transferred to an area which is deficient in order to create the bulk necessary to place an implant. Bone graft material can either be harvested from near the implant site, or processed from synthetic or other calcified sources. (for example, specially processed cow bone). They serve as the supporting framework in areas of missing bone. Whatever the source, even if it is your own bone, the body would then initiate its healing process and remodel the graft material into fully functional bone.
Why is there a need to do a bone graft
When teeth are missing or extracted, the jawbone in which it is anchored is lost as well, reducing the amount of support for face and lips creating a sunken and aged appearance. The overlying gum also recedes creating unsightly gaps and spaces between teeth. As bone is required in order to place implants, there is a need to “grow back the bone”. Thankfully, even if teeth have been lost for a long time, implants can still be placed after regenerating the jaw bone using a combination of bone grafts and special membranes.
How long does it take for the bone to grow back?
In general, it takes around 4 months for bone to grow back and regain strength. When powdered bone from a synthetic or alternative source is used, it might take a few additional months for the body to replace it with its own new bone. There is no upper age limit and as long as you are suitable for surgery, it can be performed as the process of bone regeneration will occur even in older individuals. The same principles of healing after a fracture apply, that is the area should be stabilised and left undisturbed, and is free from infection.
How can we speed up the bone regeneration process?
Healing can be speeded up through the use of bone growth factors derived from your own body. Around 20ml of blood is first drawn from your forearm and a special machine, called a centrifuge, used to spin some blood drawn from your vein. This separates blood into different layers. The clear liquid layer, termed PRP (platelet rich plasma), contains cells and factors which promote the regeneration of bone. This is then used in combination with the bone particles to form a spongy like substance which can form the scaffold on which your body regenerates its own bone.
How successful are bone grafts
Bone grafts have a success rate in excess of 90% though it also depends on the experience of the dentist, the size and shape of the defect and also the general health of the patient. Success is lower in areas where it is difficult to create and maintain the space for the bone to grow into such as in the front part of the upper jaw if it has already severely resorbed and in the back of the lower jaw near where the nerve exits the bony canal as it is difficult to manipulate the surrounding tissues. Success may also be affected if the patient is a smoker or in patients with diabetes.
What are sinus lifts and grafts
The maxillary sinuses are air spaces which lie just above and around the roots of our back teeth. When these teeth are lost, the sinus often expands downwards causing severe bone loss. We can gently push the floor of the sinus upwards when we are placing the implant but if the floor has dropped significantly, we may need a surgical procedure to directly access the sinus from the side by creating a small window from which we can push the sinus floor upwards and pack the area below with a big bulk of bone graft material. This will allow implants to be placed in future.