Bone Grafting in Preparation for Dental Implants
Bone GraftingOver a period of time, the jawbone associated with missing teeth atrophies (melts away) or is reabsorbed. This often leaves a condition in which there is poor quality and quantity of bone suitable for placement of dental implants. In these situations, most patients are not immediate candidates for the placement of dental implants.
Today, we have the ability to grow bone where needed. This not only gives us the opportunity to place implants of proper length and width, it also gives us a chance to restore functionality and aesthetic appearance.
Types of Bone Grafting
Minor bone grafting such as immediate socket grafting after an extraction, can repair potential implant sites with inadequate bone structure due to previous extractions, gum disease or injuries. The bone is either obtained from a tissue bank (bone in a bottle) or your own bone is taken from the jaw, hip or tibia (below the knee). Sinus lift bone grafts are also performed to replace bone in the posterior (back) upper jaw. In addition, special membranes may be utilized that dissolve under the gum and protect the bone graft and encourage bone regeneration. This is called guided bone regeneration or guided tissue regeneration. Zygomatic (longer dental implants) may eliminate the need for some types of grafting.
Major bone grafts are typically performed to repair defects of the jaws. These defects may arise as a result of traumatic injuries, tumor surgery, or congenital defects. Large defects are repaired typically using the patient’s own bone. This bone is harvested from a number of different sites depending on the size of the defect. The skull (cranium), hip (iliac crest), and lateral knee (tibia), are common donor sites. These procedures are routinely performed in an operating room and may require a hospital stay. Fortunately, these procedures are infrequent for the majority of patients.
The use of Zygomatic and Pterygoid Implants along with All on Four Procedures using 3D technology in our scanner has virtually eliminated the large grafts except for a minority of patients with extremely large defects.
Sinus Lift (Augmentation) Procedure
The maxillary sinuses are behind your cheeks and on top of the upper teeth. Sinuses are like empty rooms that have nothing in them. Some of the roots of the natural upper teeth extend up into the maxillary sinuses. When these upper teeth are removed, there is often just a thin wall of bone separating the maxillary sinus and the mouth. Dental implants need bone to hold them in place. When the sinus wall is very thin, it may not be possible to place traditional dental implants in this area.
There is a solution and it’s called a sinus graft, sinus lift, or a sinus augmentation graft. Dr. Lippisch or Dr. Engebretsen enters the sinus from where the upper teeth used to be. The sinus membrane is then lifted upward and donor bone is inserted into the floor of the sinus. Keep in mind that the floor of the sinus is the roof of the upper jaw. After several months of bone consolidation, the grafted bone becomes part of the patient’s jaw and dental implants can be inserted and stabilized in this new sinus bone.
The sinus graft makes it possible for many patients to have dental implants when years ago there was no other option and either a fixed bridge was fabricated if there was a sufficient number of remaining teeth or a removable partial denture was made.
If enough bone between the upper jaw ridge and the bottom of the sinus is available to stabilize the implant well, sinus augmentations and dental implant placement can sometimes be performed as a single procedure. If not enough bone is available, the sinus augmentation will have to be performed first, then the graft will have to mature for several months. Once the graft has matured, the implants can be placed.
Ridge Expansion for Dental Implants
In severe cases, the ridge has been reabsorbed and a bone graft is placed to increase ridge height and/or width. This is a technique used to restore the lost bone dimension when the jaw ridge gets too thin to place conventional implants. In this procedure, the bony ridge of the jaw is literally expanded by mechanical means. Bone graft material can be placed and matured for a few months before placing the implant.
This is a very infrequent procedure in this day and age with the advent of shorter implants, angled abutments and tilted implants. Since this procedure is considered a very aggressive approach (there is almost always some postoperative numbness of the lower lip and jaw area, which dissipates only very slowly, if ever), usually other, less aggressive options are considered first.
The inferior alveolar nerve, which gives feeling to the lower lip and chin, may need to be moved in order to make room for placement of dental implants in the lower jaw. This procedure is limited to the lower jaw and indicated when teeth are missing in the area of the two back molars and/or and second premolar, with the above-mentioned secondary condition.
In many cases, we can use allograft (Human) material to implement bone grafting for dental implants. This bone is prepared from cadavers and used to promote the patients own bone to grow into the repair site. It is quite effective and very safe. Synthetic materials can also be used to stimulate bone formation. We even use factors from your own blood (PRP) to accelerate and promote bone formation in graft areas.
These surgeries are performed in the office surgical suite typically under IV sedation or general anesthesia. After discharge, bed rest is recommended for one day and limited physical activity for one week.