After your tooth is lost, the jawbone around the missing tooth slowly atrophies or is reabsorbed. After a period of time, this often results in poor quality and quantity of bone available for the ideal placement of implants. In these circumstances, the dental implants position and size may not be optimal for your future crown or denture.
Today, we now have the technology to grow bone where needed. These surgeries are known as bone grafting procedures and they give us the ability to place the implants in its ideal place as well as using the optimal length and width for the implant. More importantly, it also gives us a chance to create a better aesthetic appearance and functionality of the future prosthesis on the implant.
Major Bone Grafting
When you have inadequate bone structure due to previous extractions, gum disease or injury, you need bone grafting procedures to build the bone up for implants. The bone graft is usually obtained from a tissue bank and avoids a secondary surgery to obtain the bone. However, certain cases require your own bone and this may be taken from another part of your jaw. If the bone loss is extensive, you may require more complex surgery. If you require a lot of bone, oral and maxillofacial surgeons are able to harvest this bone from your tibia (below your knee), iliac crest (hip), and cranium (skull). These procedures are commonly performed in an operating room and may require a hospital stay.
Sometimes special membranes may be utilized by your surgeon to protect the bone graft and encourage bone regeneration. This is called guided bone regeneration or guided tissue regeneration. This special membrane may be collagen-based and therefore dissolves under the gum. Other membranes may be titanium based and will require retrieval at the time of implant placement.
Sinus Lift Procedure
The maxillary sinuses are located behind your cheeks, above your upper teeth, and on either side of your nose. Sinuses are like empty rooms in your bone with nothing in them. When your teeth are lost, the bone below your sinus shrinks in height and width. If there is inadequate height of bone, the dental implants will protrude into your sinus. Dental implants need bone to hold them in place.
There is a very simple solution to this and it is called a sinus lift or sinus bone graft surgery. It is a straightforward procedure performed by the oral and maxillofacial surgeon. The surgeon will enter the sinus where the upper teeth used to be and lift up the sinus membrane. Donor bone can then be inserted into the space created by lifting the sinus membrane. This donor bone will then be incorporated to your jaw bone and now you have an increased amount of bone height for the implant. The dental implant can be placed at the same time as the sinus lift procedure or can be placed after several months of healing of the sinus bone graft.
If enough bone between the upper jaw ridge and the bottom of the sinus is available to stabilize the implant well, sinus augmentations and implant placement can sometimes be performed as a single procedure. If not enough bone is available, the sinus augmentation will have to be performed first, then the graft will have to mature for several months, depending upon the type of graft material used. Once the graft has matured, the implants can be placed.
In severe cases, the ridge has been reabsorbed and a bone graft is placed to increase ridge height and/or width. This is a technique used to restore the lost bone dimension when the jaw ridge gets too thin to place conventional implants. In this procedure, the bony ridge of the jaw is literally expanded by mechanical means. Bone graft material can be placed and matured for a few months before placing the implant.