An implant-supported bridge is similar to a regular dental bridge, but it is supported by implants and not by natural teeth. In most cases, when an implant-supported bridge is used, one implant is placed in the jawbone for each missing tooth. Then the crownsare connected to each other to form one piece.
An implant-supported bridge is used when more than one tooth is missing. It also may be used when your dentist is concerned that you might put too much pressure on individual implants that are not connected to each other. For example, clenching or grinding your teeth can put a lot of pressure on individual implants. This can increase the chances that they will loosen from the bone and fail.
An implant-supported bridge reduces the pressure on the individual implants in the bone, and spreads it across the entire bridge. If the implants will be placed next to natural teeth, the natural teeth and surrounding gums must be in good health. If you don’t have enough bone to place and support the dental implants, the supporting bone can be built up using bone augmentation or grafting before the actual implant procedure begins.
In some cases, your dentist may not want to put an implant in a certain place in your mouth. There may not be enough jawbone to support an implant, or the location may be too close to a nerve or sinus cavity (located above your upper teeth). In that case, your dentist can avoid the area by placing implants on both sides of the space. An implant-supported bridge will be placed on top. An implant-supported bridge also can be made similar to a traditional bridge, with a crown suspended between two implant-supported crowns.
An implant-supported bridge consists of:
- The implant is made of titanium and surgically placed in the jawbone. You may have one implant for each missing tooth. In other cases, your dentist may skip one or more spaces because there’s not enough jawbone, or because the space is too close to a nerve or your sinus cavity.
- The abutment, a cylinder made of titanium, gold or porcelain, is screwed onto the implant. In the past, some abutments were attached to the implant using cement. Today all abutments are secured with screws. Abutments can be pre-fabricated or custom-made by the dental lab.
- The restoration (the part that looks like teeth) is a series of crowns connected to form a bridge. They are made of porcelain attached and fused to a substructure of metal.
The time it takes to complete the implant process depends on many factors. When the traditional method of placing an implant is used, the shortest time frame is about five months in the lower jaw and seven months in the upper jaw. This includes surgeries and the placement of the implant-supported bridge. However, the process can last a year or more, particularly if bone needs to be built up first. More recently, many dentists have been placing an implant and crown in a single visit. Two surgeries usually are needed to place and prepare the implant. During the first surgery, the implant is placed in the jaw and covered with gum tissue. At the end of the healing period the implant is exposed so that the bridge can be placed.
We will do a comprehensive examination. During the exam, he or she will review your medical and dental histories, take X-rays and create impressions of your teeth and gums so that models can be made. In some cases, a computed tomography (CT) scan of your mouth. This will show where your sinuses and nerves are. The dentist can then make sure that they will not be affected by the implants. If the X-rays and CT show that your jaw does not have enough bone to hold an implant, the dentist can discuss options. These include bone grafting or bone augmentation, for building up the bone. The bone can be taken from your own mouth, chin or hip, or processed cadaver bone or cow bone can be used. If you need one of these procedures, it will take about four months for the bone to be ready for the implant.
Once it’s determined that you have enough bone to successfully hold an implant, you will schedule the first surgery. This involves placing the implant or implants in your jaw. We will plan the placement of the implants carefully to make sure that their position allows your new bridge to look natural. To help determine where the implants should be placed, we create a model, called a wax-up, of what the bridge will look like when it is completed. To do this, we use a model of your mouth made from impressions taken of your teeth and jaw. Using the wax-up, your dentist will make a surgical guide. The surgical guide is a clear piece of plastic similar to a mouth guard. It fits over your existing teeth and extends over the area where teeth are missing to show where the implants need to be placed.
After the first surgery, the specialist will wait till the bone and the implants fuse to one another. There are several types of implants. The most popular type is the root-form implant, designed to serve as a tooth root. It is placed in the jawbone in the space created by the missing tooth.
Once the implants have become fused with the bone, you can schedule the second surgery. Your dentist will confirm whether the implants are ready for the second surgery by taking X-rays. This surgery is simpler than the first. A small incision is made in your gums to expose the tops (heads) of the implants. A collar, called a healing cap, is placed on the head of the implant after it is exposed. This guides the gums to heal correctly. The collar is a round piece of metal that holds the gums away from the head of the implant. The collar will be in place until the temporary bridge is inserted.
There are many types of implant-supported bridges. They can be held on by cement or with screws. They can be attached directly to the implant or to an abutment. Your dentist will determine which type will work best for you. If a screw-retained bridge will be used, the first step is to remove the healing cap and screw a permanent abutment into the implant. An impression will be made with the abutment in place. The abutment is shaped like a natural tooth that has been cut down to fit inside a crown.
At the next visit, the temporary bridge will be placed on the abutments. The temporary bridge will stay in place for four to eight weeks. The temporary bridge is made of softer material than the permanent bridge. The softer material helps to cushion and protect the implant from the pressure of chewing. During the next visit, your dentist will test the fit of the metal framework that supports the porcelain bridge. If the framework doesn’t fit correctly, it will have to be adjusted and you will have to return for another try-in. It might take several visits before the fit is right. If the teeth will not be connected, each tooth will be tried. Once the metal framework fits, the rest of the bridge will be completed, and it will be placed in your mouth and secured.