Bone Grafting

Bone grafting is often closely associated with dental restorations such as bridge work and dental implants. In the majority of cases, the success of a restoration procedure can hinge on the height, depth, and width of the jawbone at the implant site. When the jawbone has receded or sustained significant damage, the implant(s) cannot be supported on this unstable foundation and bone grafting is usually recommended for the ensuing restoration.

There are several major factors that affect intra-oral bone volume:

• Periodontal Disease – Periodontal disease can affect and permanently damage the jaw bone that supports the teeth. Affected areas progressively worsen until the teeth become unstable.
• Tooth Extraction – Studies have shown that patients who have experienced a tooth extraction subsequently lose 40-60% of the bone surrounding the extraction site during the following three years. Loss of bone results in what is called a “bone defect”.
• Injuries and Infections – Dental injuries and other physical injuries resulting from a blow to the jaw can cause the bone to recede. Infections can also cause the jaw bone to recede in a similar way.

Reasons for bone grafts

Bone grafting is a highly successful procedure in most cases. It is also a preferable alternative to having missing teeth, diseased teeth, or tooth deformities. Bone grafting can increase the height or width of the jawbone and fill in voids and defects in the bone.

There are essentially two basic ways in which bone grafting can positively impact the health and stability of the teeth:

Reconstruction – Bone grafting stabilizes and helps restore the jaw foundation for restorative or implant surgery. Deformities can also be corrected and the restructuring of the bone can provide added support.

Preservation – Bone grafting can be used to limit or prevent bone recession following a tooth extraction, periodontal disease, or other invasive processes.

Oral Examination

Initially, your periodontist will thoroughly examine the affected area in order to assess the general condition of the teeth and gums. If periodontal disease is present or the adjacent teeth are in poor condition, these factors will be fully addressed before the bone grafting procedure can begin. Routinely, a 3 dimension Cone Beam Computerized Tomogram will be completed to accurately assess the extent of the patients bone defect.

What Types of Materials are Used in Bone Grafting?

A bone graft may be required to create a stable base for dental implant placement, to halt the progression of gum disease or to make the smile appear more aesthetically pleasing.

There are several types of dental bone grafts.  The following are the most common:

• Autogenous bone graft – In this type of graft the bone is removed from elsewhere in the body and implanted in the mouth. The most common donor site for autogenous bone grafting is the posterior third molar areas of the lower jaw. 
  
  
• Allograft – Allograft refers to Human derived donor bone and is routinely used in periodontal and dental implant reconstruction. It is sourced from reputable tissue banks that undergo strict processing and sterilization procedures.
  
  
• Xenograft – Xenograft refers to bone graft material derived from another species. In dentistry the most commonly utilized xenograft is bovine bone.  A xenograft is perfectly safe and has been used successfully for many years.  Ample bone can be obtained and no secondary donor site is necessary.

Reasons for bone grafting

There are a wide variety of reasons why bone grafting may be the best option for restoring the intra-oral bone.

Dental implants – Implants are the preferred replacement method for missing teeth because they restore full functionality to the mouth; however, implants need to be firmly anchored to the intra-oral bone to be effective.  If the intra-oral bonelacks the necessary quality or quantity of bone, bone grafting can strengthen and thicken the implant site.

Sinus lift – A sinus lift entails elevating the sinus membrane and grafting bone onto the sinus floor so that implants can be securely placed.

Ridge augmentation – Ridges in the bone can occur due to trauma, injury, birth defects or severe periodontal disease.  The bone graft is used to fill in the ridge and make the intra-oral bone a uniform shape.

Nerve repositioning - If the inferior alveolar nerve requires movement to allow for the placement of implants, a bone grafting procedure may be required.  The inferior alveolar nerve allows feeling and sensation in the lower chin and lip.

What does bone grafting treatment involve?

Bone grafting is a surgical procedure which may be performed under local anesthetic but often involves IV sedation.

Initially, the grafting material needs to either be harvested or prepared for insertion.  A small incision is made in the gum tissue and the soft tissues are gently separated from the bone.  The bone grafting material is then placed at the effected site. A collagen membrane is routinely used to help secure and stabilize the bone graft. This product aids in the formation of good quality bone. The overlying soft tissues are then carefully and securely closed to ensure rapid wound healing.

The bone regeneration process may be aided by:

• Guided bone/tissue regeneration – A thin barrier (membrane) is placed below the gum line over the grafting material.  This barrier creates enough space for healthy tissue to grow and separates the faster growing gum tissue from the slower growing bone.  This means that bone cells can migrate to the protected area and grow naturally.
  
  
• Tissue stimulating proteins – Enamel matrix proteins occur during natural tooth development.  Emdogain is a matrix protein product which is usually placed on the affected site before the gum is sutured.  It mediates the formation of accellular cementum on the tooth which provides a foundation to allow periodontal attachment to occur.  Tissue stimulating proteins help to create lost support in areas affected by periodontal defects.
         

The overlying gums are sutured in place and a follow up appointment will need to be made within 10 days to assess progress.  Bone grafting is a highly successful treatment and a good base for further periodontal restorations.

If you have any questions about bone grafting, please ask your dentist.