For more than 50 years people have been able to smile with pride thanks to the revolutionary work of Per-Ingvar Brånemark, a Swedish physician and researcher, who is considered the “Father of the Modern Dental Implant”. Brånemark, while studying blood flow in rabbits in the 1950s, discovered that titanium could fuse with bones and he coined the term osseointegration to describe the process. By 1965 Brånemark was able to perform the first titanium dental implant on a human volunteer with Gösta Larsson who was able to use his implants the rest of his life, for 40+ years.
To this day dental implants continue to be the best solution for missing teeth, but the quality of jawbone where the implant is placed is not only key to the success of the procedure, but in some cases an implant placement cannot take place without adequate bone support. The good news is that even in patients without adequate jawbone for implants, a bone graft can be used to increase jaw width and/or height along the small, bony ridge in the upper (maxilla) or lower (mandible) jaw where teeth sockets are located, to prepare those sites for dental implant placement.
Why Ridge Expansion or Modification is Needed
There are many reasons why the bone in the upper or lower jaw may be inadequate for dental implants.
Some of the reasons for this loss of bone are:
- Missing teeth: The moment a tooth is lost in the mouth, the body starts to naturally stop supporting the bone in the area, leading to 25 percent bone loss within a year and up to 40 percent within three years.
- Periodontal disease may lead to tooth loss and bone loss in the mouth.
- Smoking is a big risk factor for periodontal disease with some studies showing heavy smokers with five times more severe bone loss compared to those who have never smoked.
- Misaligned teeth that affect normal chewing can lead to bone loss.
- Trauma can lead to missing teeth and bone loss.
- Wearing dentures can cause bone loss because of a lack of pressure applied to the bone when chewing.
- Other developmental issues can lead to bone loss.
Steps in a Ridge Expansion or Modification
Ridge expansion, also called ridge modification or ridge augmentation, is a technique used to restore lost bone dimension in the jaw ridge by adding grafting material which bonds with the natural bone and then encourages bone growth. For most patients, ridge expansion is done prior to dental implant placement with four months between procedures being a typical period. There are cases, however, where longer than four months are needed before an implant can be placed, and there are other circumstances where the ridge expansion and dental implant can be done at the same time.
Steps for a ridge expansion:
- The gum is lifted away from the bony ridge to expose the defect area.
- The defect is then filled with bone from a healthy spot in the patient or a bone substitute. These materials build up the ridge.
- The incision is then closed to allow healing to begin.
Ridge expansion not only prepares the patient for future dental implants, but helps the jaw maintain a natural appearance and prevent the continued loss of bone.
Type of Bone Graft Material Used for a Ridge Expansion
The preferred material for a bone graft is the patient’s own bone, called an autograft. Bone is typically taken from the inside of the mouth in the chin area, third molar region or in the upper jaw behind the last tooth. When a greater quantity of bone is needed, then the grafting material can be taken from the tibia at the knee, or it can also be taken from the hip region. If bone is used from other humans, it is called an allograft. Cadavers are usually the source and the materials are attained from reputable tissue banks. The cadaveric bone is treated and purified multiple times and is immune to reaction. A third option is to use animal bone, usually bovine, for a bone graft. This process is called xenograft. These animal bones are chemically treated prior to use and are comparable to human bone material.
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