Bone Grafting

Bone Grafting 

When one loses one or more of their natural teeth, the jawbone starts to degrade at a faster rate. This means that the rate of new bone formation is lesser than its degradation. If missing teeth are not replaced timely, the residual brittle and the weaker jawbone is unable to support dental implants firmly. Many patients are not suitable candidates to get their missing teeth replaced with dental implants in these cases. 

However, this does not mean that they cannot get dental implants. Thanks to bone grafting, people with insufficient bone density and strength can still get dental implants. Bone grafting is also beneficial for individuals with jaw bone defects caused by disease, trauma, or cancer radiation therapy. 

What is Bone Grafting?

According to the Canadian Dental Association, a bone graft is a procedure in which new bone – obtained from a natural or synthetic source – is placed at the site where the bone tissue is insufficient to support an implant. 

What are the Different Types of Bone Grafting Procedures?

Minor Bone Grafting 

Minor bone grafting is needed to restore the strength the quality, and quantity of bone in regions where teeth have been lost for a long time. Once the graft has been placed, it will gradually fuse with the surrounding bone, resulting in a strong, dense bone that can firmly anchor dental implants for replacing missing teeth. 

Major Bone Grafting 

A major bone graft is needed when there is significant bone loss caused by trauma, underlying bone disease, or extraction of multiple teeth following cancer radiation therapy or long-standing gum disease. Generally, dentists repair large bone defects by using the patient’s own bone tissue. This type of bone graft, called an autograft, is obtained from various body sites such as the hip, skull, and lateral knee bone. Major bone grafting is performed in an operating room and requires a hospital stay. 

Sinus Lift Procedure 

The sinuses are air-filled cavities in the face, head, and neck region present on both sides of the face. The sinuses help reduce the weight of the skull and improve the quality of our voice. One of these sinuses, the maxillary sinuses, lie just above the roots of our upper molar teeth. When the upper molar teeth are removed, there is an accelerated bone loss around the sinuses, leaving only a thin bony wall separating them from the oral cavity. Besides, the maxillary sinuses also descend downwards from their position, making it difficult for your dentist to place dental implants. 

To fix this problem, your dentist will perform a sinus lift procedure. According to the Canadian Academy of Periodontology, a sinus lift procedure involves the placement of a bone graft beneath the maxillary sinus – strengthen the sinus floor – and ensure sufficient bone density, height, and quality in the region can support one or more dental implants. 

In a sinus lift procedure, your dentist will make an incision over the soft tissues covering the sinus bone. They will then enter the sinus by either drilling a hole on the side of the bone or from the upper side of the jaw. Next, your dentist will lift the membrane that covers the sinus and fill the underlying region with a synthetic or natural bone graft. The surgical site is then left undisturbed for a few months to ensure optimal bone formation. 

After a few months, your dentist will take x-ray images of the site to observe the healing progress.  Once the bone graft has fused with the neighbouring bone, your dentist can proceed with the placement of dental implants to replace the missing teeth. In some cases, your dentist may choose to perform the sinus lift and implant placement procedure simultaneously. However, this is typically done when sufficient bone tissue already exists to support the implant. 

Ridge Expansion 

The contour of the jaw bone tissue that supports our teeth – also called the alveolar ridge – is also essential in ensuring dental implant’s stability and long-term success. In cases where there is widespread resorption of the jawbone, leading to a “knife-edge” contour of the alveolar ridge, implant insertion becomes complicated with a higher risk of implant failure.

To fix this situation, your dentist will expand the thickness of the bone by adding a bone graft – to obtain a rounded bone contour that can firmly anchor an implant or even support and retain a removable denture. 

Nerve Repositioning 

The inferior alveolar nerve is one of the essential sensory nerves of the face, which supplies innervation to the lower teeth, the chin and the lower lip. In the case of excessive bone loss in the lower jaw, the alveolar nerve lies very close to the jawbone’s surface. As a result, the nerve may be damaged if your dentist plans to insert an implant to replace the lower molar teeth. To prevent this problem, your dentist will perform a nerve positioning procedure. According to the International Congress of Oral Implantologists, a nerve repositioning procedure involves redirecting the course of the inferior alveolar nerve in severely resorbed lower jaws so that the dentist can use longer implants to ensure optimal implant stability and retention. 

What are Different Types of Bone Grafts Used in Dentistry?

Depending on the extent and the location of bone resorption, your dentist may use different types of bone grafts. 

1. Natural Bone Grafts 

These bone grafts are obtained from natural sources. Your dentist may use bone graft from the patient’s own body or a another human’s bone tissue. A xenograft, on the other hand, is also obtained from natural sources but other species, such as from bovine or porcine sources. However, the best results are achieved when the patient’s own bone tissue is used for grafting, as it carries a lower risk of graft rejection or other surgical complication. In cases where repair of large bone defects is needed, allografts may be used. Allografts are bone grafts that are obtained from cadavers. 

2. Synthetic Bone Grafts

Nowadays, bone grafts made from synthetic sources like hydroxyapatite and calcium phosphate – which are the building blocks of bone tissue – are also available. The advantage of synthetic bone grafts is that their properties, such as their strength, degradation rate and speed of new bone formation, can be easily tailored according to the intended application. Your dentist may also use various growth factors to accelerate the bone formation process. 

After a thorough clinical and radiographic examination of your oral cavity, your dentist will advise whether you need to undergo any of the above-mentioned bone grafting procedures before implant therapy. Some patients may require more than one bone grafting procedures to become suitable candidates for getting dental implants. While some of these procedures may be performed at the dental chairside, others are performed in an out-patient hospital under the effect of general anaesthesia, sometimes needing hospital admission. After getting discharged from the hospital, you may be advised to take bed rest and limit physical activity to ensure optimal healing.