Bone Grafting

To ensure the success of your implants and the artificial teeth or “prosthesis” they will support, it is very important that you have enough good quality bone in your jaw. If the walls of the socket are thick enough after you have a tooth removed the bone will usually fill in the space within three months. However it is not unusual for patients to be missing bone after teeth have been extracted and not replaced for a long time. This is particularly true after an accident or as a result of gum disease or defects from an extraction, cysts or previous tumor surgery. A bone graft can then be performed. This is surgical procedure that replaces your own bone with material from another site in your own body or from a synthetic or natural bone substitute. The bone graft fills in the missing bone but also stimulates the growth of your own bone that acts as a strengthening bridge between the graft and your existing bone. Over time, most of the graft material will be replaced by your own newly formed bone.

When a tooth is removed the supporting jaw-bone usually begins to resorb or melt away within three to six months after the time of the extraction. The speed of this resorbtion is affected by many factors including how carefully the tooth is removed and any existing severe gum disease that may have already caused some bone loss to be present in the area.

When we plan for the replacement of a tooth with a dental implant, we ideally like to place the implant in a position similar the where the tooth was initially. If the bone has melted away (or resorbed) to any great extent, it may be necessary to build up this bone with a bone graft before being able to place the implant in an ideal location. If a large amount of bone is missing, the graft procedure usually needs to be done in two separate stages. First the bone is grafted from another part of the lower jaw and then the implant is placed during a second surgery after the graft has healed for 4 to 6 months.

Although your surgeon often knows in advance when a graft will be necessary, at times this is only discovered when the implant site is opened during surgery and he is prepared to replace the necessary bone. Patients report that the procedure causes little discomfort. The implants placed show equal success rates as those done without bone grafting. Please call us if you'd like to find out if you are a candidate for bone grafting in Montreal, Quebec.

Where does the bone graft material come from?

The simplest source that gives best results is the patient’s own bone material collected while the implant site is being prepared. When larger amounts of bone are required they can be removed from the inside of the mouth, third molar region or chin, the lateral knee or from the hip. In case of the hip and knee, the procedure is usually performed in a hospital setting under general anesthesia.

Alternatively “bone in a bottle”, prepared by a special process from cadavers is commonly used. This method is very safe and effective. Because of the concern for disease transmission, other sources of bone substitutes have also been developed including; processed bone from animal sources (such as cows) and synthetic materials.

Patients should be reassured that they will be consulted in all cases regarding the source of bone to be used for their specific situation.

Healing Period After Bone Grafting

The healing period required after a bone graft ranges between three and nine months, depending on the individual case. The implant can be placed once the graft is completely healed. In some cases, implant placement and bone grafting can be done at the same time.

Sinus Lift

It is very common for the upper back jaw to be missing good quality bone since it is very close to the sinus, which is an air-filled cavity. The sinus cavity may be very large or very low and extend into the areas where the implant needs to be placed. A procedure called a sinus lift can be performed in which the membrane that lines the sinus cavity is raised. The space beneath is then filled with bone graft material. This procedure can often be performed in the dental office under local anaesthesia or sedation when the implant is being placed. Sometimes in more complex cases, it is necessary to do this procedure under general anesthesia and to place the implants in a separate procedure after the bone graft has healed.

In some situations when an upper molar tooth is removed, a certain amount of supporting bone melts away (resorbs). This can result in an inadequate quantity of bone height to allow the implant to be properly anchored in the bone. When teeth are missing in the back region (molar) of the upper jaw, we can sometimes gain this height of bone by lifting the floor of the sinus and filling the space with bone grafting material and some natural bone that can be spared from another part of the upper or lower jaw bone. Sometimes implants can be placed at the same time as the bone graft (or sinus lift) is performed. In other cases it is necessary to wait 3 to 6 months for the graft in the upper jaw to heal.

Ridge Modification

You may have a defect in your jaw caused by wearing dentures, gum disease, an accident or defects that you have had since birth. This can be corrected by a procedure known as “ridge modification” in which the gum is lifted and the bony defect is exposed and filled in with graft material to build up the bone. This makes it possible to successfully place the implant and correct the unattractive indentation in the gum line caused by the defect. The healing time required before implant placement varies between 4 and 12 months. In some instances, the implant can be placed immediately.