Why is bone grafting required?
When teeth are lost, the underlying supporting alveolar bone no longer receives adequate stimulation from forces on your teeth. This can cause your bone to shrink away or ‘resorb’ both vertically and horizontally.
Alveolar bone can shrink due to:
- teeth missing for a long time
- prosthetically replaced teeth with removable dentures
- teeth lost due to advanced gum disease, known as ‘periodontal disease’
Without enough jaw bone available, dental implants of sufficient size cannot be placed in your mouth.
Bone grafting may also be required if your jaw bone is defective, and not strong enough to accommodate dental implants, caused by:
- root canal infection
- fractured teeth
- difficult tooth removal
What does pre-planning for implants and socket preservation involve?
Having a bone graft performed at the time of tooth removal is commonly recommended specifically when future dental implant work is planned, even up to five years in advance. In short, the bone graft helps maintain the existing jaw bone and ensures a greater chance of successful implant placement into abundant bone tissue. This also reduces the need for separate grafting procedures, which would increase costs and possible complexity.
If the bony walls of your tooth socket are damaged, socket preservation may be undertaken to rebuild the walls to an appropriate height and width using a barrier membrane.
During this procedure, the gums surrounding the socket are separated from the bone to expose the remaining bone and a sheet of special material is placed under the gum. This material prevents gum cells from entering the socket and, therefore, allows the slower-moving bone cells to grow and fill out the socket to an adequate dimension to receive an implant.
What is sinus grafting?
The maxillary sinuses are hollow, air-filled spaces in the bone above your upper back teeth, between your teeth and your eye sockets. They are one of the five pairs of sinus cavities throughout your skull bones.
When your upper back teeth, usually molars and premolars, are lost, the maxillary sinus cavity tends to expand and drop into your jaw bone, occupying the area of the missing teeth, in a process known as ‘pneumatisation’.
Sinus grafting allows the floor of your sinus cavity to be lifted up and bone graft materials placed in the space to stimulate adequate growth of bone for implants to be placed. Even if your teeth are still present, there is sometimes not enough bone height between your sinus floor and your gum to allow adequately sized implants to be placed.
Sinus grafting can be done as a preliminary surgery, to prepare the bone for implant placement, or performed at the same time as the implant placement if there’s enough bone to stabilise the implants while they heal.
What is an osteotome sinus lift?
An alternative approach, to increase the bone height under your sinuses, is an osteotome sinus lift.
In this procedure, a small amount of bone is left under the sinus cavity floor at the implant placement site. Blunt instruments, called osteotomes, are used to push up the bone retained, along with the lining of the sinus cavity itself.
This raises the floor of the sinus in the area where the dental implant will be placed, thereby enabling a longer implant of more adequate proportions, which in turn provides more stability and strength to receive the forces of chewing.