Sinus augmentation and bone grafting

Sinus augmentation has become more common during the last 15 years as more people get dental implants to replace missing teeth.

A sinus lift, or graft, is carried out when there is not enough bone height in the upper jaw (or the sinuses are too close to the jaw), for dental implants to be placed. There are several reasons for this:

• Many people who have lost teeth in their upper jaw (particularly the back teeth, or molars) do not have enough bone for implants to be placed.  (Because of the anatomy of the skull, the back of the upper jaw has less bone than the lower jaw)
• Bone may have been lost because of periodontal (gum) disease
• Tooth loss may have led to a loss of bone as well. Once teeth are gone, bone begins to be resorbed. If teeth have been missing for a long time, there often is not enough bone left to place implants.

In these instances additional bone height is needed to place a sufficiently long implant with the correct crown-to-root proportions.  This is achieved by either a sinus lift or a sinus graft (or augmentation).

What is sinus augmentation?

When teeth are present they retain the bone around the roots. Following an extraction of upper molars and premolars the height of bone often reduces.
The maxillary sinus may have enlarged and the amount of bone available is reduced, preventing placement of implants.  The shape and the size of this sinus varies from person to person. The sinus can also get larger as you age.

A sinus lift is when the bone that makes the floor of the sinus (and is above the end of the root), is fractured and gently manipulated upwards to facilitate placement of a longer implant. With careful planning and manipulation, the patient's own bone in the area of the root can be moved upwards as the sinus floor is fractured.

Sinus graft surgery adds bone to the upper jaw in the area of the molars and premolars. It's sometimes called a sinus augmentation. The bone is added between the jaw and the maxillary sinuses, which are on either side of the nose. To make room for the bone, the sinus lining has to be moved upward.

Creating bone this way facilitates implant placement.

Preparation for surgery

The biomaterial used in a sinus graft may come from your own body (autogenous bone), or from a cadaver (allogenic bone) or from cow bone (xenograft).

You will need a CBCT taken before the sinus graft so the dentist can study the anatomy of your jaw and sinus. This scan will allow the dentist to accurately measure the height and width of your existing bone and to evaluate the health of your sinus, ensuring there is no pre-existing pathology in the location.

If you suffer from seasonal allergies, such as hay fever, your will need to schedule the procedure at a time when you won't have symptoms of sneezing or a blocked nose.

How the surgery is done

The surgeon will cut the gum tissue where the back teeth used to be. The tissue is raised, exposing the bone. A small, oval window is opened in the bone. The sinus lining which is attached to the bone separates the sinus from the jaw. This lining is gently pushed up and away from the jaw.

Granules of biomaterial material are then packed into the space where the sinus was.  The amount of material used will vary, but usually several millimetres of height is added above the jaw.

Once the material is in place, the wound is closed with stitches. The implants will be placed four to six months later. This allows time for the grafted material to mesh with your bone. If there is sufficient bone present to facilitate stability of the implants, the implants can be placed simultaneous to sinus grafting, reducing the need for multiple surgeries.

Post operation

Following the procedure, you may have some swelling in the area. You may experience bleeding from your mouth or nose.  It is extremely important that you do not blow your nose or sneeze forcefully for a period of 2 weeks. Either one could cause the biomaterial to move, and loosen the stitches.

You will be given pain medicine, an antibiotic and an antimicrobial mouthwash to help prevent infection. Most patients have only a little discomfort after a sinus graft procedure.

You will see the dentist after 7 to 10 days. They will evaluate the surgical site and remove stitches. You might be asked to return a few more times to make sure the area is healing properly.

After a sinus graft, you'll need to wait several months for the material to be replaced by bone and integrate with your jaw. Depending on the grafting material used, implants may be placed in four to nine months.

Using PRGF to help the new bone harden faster

Proteins called ‘plasma rich growth factors’ help the new bone harden faster. Platelet rich plasma, which contains the growth factors, is taken from your blood before surgery and mixed with the graft that is placed into your sinus. PRGF is a state-of-the-art and natural way of speeding up your body's ability to heal.

Surgery risks

The main risk is that the sinus lining could be punctured or torn. If the lining is torn during the procedure, the dental surgeon will either stitch the sinus tear or place a patch over it. If the repair is not successful, the dental surgeon may stop the procedure and allow the perforation time to heal.

The dentist can redo the sinus graft once the lining has healed. This usually takes a few weeks. A healed sinus lining tends to be thicker and stronger which means a second attempt at a sinus lift is likely to be successful. However, other factors also affect success.

Infection is a risk of any surgical procedure. However this rarely occurs after sinus grafts.

On rare occasions the existing bone does not integrate with the biomaterial material, and the grafted area does not develop a blood supply. If this happens, any implants placed in this area will fail because there is no live bone for them to attach to. If this happens you may opt to have the sinus graft procedure repeated.

For more information on dental implants, why not visit our dedicated site for our Life-Changing Dentistry practice.