| Types of Implants
Today, most dental implants are made of titanium, a metal that has special qualities that make it useful for this purpose.
Titanium develops a thin film on its surface that protects it from corrosion. It is resistant to acids, salt solutions and oxygen, among other things. Titanium also is almost completely nonmagnetic. It is extremely strong for its weight.
Perhaps most important, the body does not reject titanium implants as foreign objects. When implants are placed in bone, the bone grows around the implant. The process is called osseointegration.
Titanium implants come with many types of surfaces, including:
- Acid etched
- Plasma sprayed
- Acid etched and grit blasted
- Hydroxyapatite coated
Hydroxyapatite is a part of what bone is made from. It bonds with bone in a process called biointegration.
There are several types of implants. Root-form implants are by far the most popular. Transosseous implants also are performed occasionally. The other types are used rarely.
Your dentist decides which type of implant to use based on the quality of the bone in your jaw and the type of crown, bridge or denture that will be placed on the implant.
Root-form implants are called endosseous or endosteal implants, meaning they are placed in the bone. They look like screws, thick nails or cones, and come in various widths and lengths. For root-form implants to be successful, the bone needs to be deep enough and wide enough to provide a secure foundation.
Root-form implants can be inserted in two stages or one stage. The two-stage process is the traditional way. In this procedure, the implant is "buried" under the gum tissue for three to four months. Then it is exposed during a second surgical procedure. In a single-stage procedure, the implant is placed in the bone and remains exposed in the mouth.
Transosseous implants originally were designed to be used in people who had no bottom teeth and very little bone in the lower jaw. However, they are rarely used today because placing them requires extensive surgery, general anesthesia and a hospital stay. Also, their use is limited to the lower jaw.
Placing transosseous implants involves inserting two metal rods from below the chin, through the chin bone and into the mouth. The ends of the rods can be seen inside the mouth. These are used to attach a denture.
Most dentists today prefer to use bone grafts or another endosseous implant method instead of the transosseous method. They are equally effective and do not require the level of surgery needed for transosseous implants.
This type of implant can be used if the lower jawbone is too thin for a root-form implant. A Ramus-frame implant is embedded in the jawbone from the back corners of the mouth (near the wisdom teeth) to near the chin. Once it is inserted and the tissue heals, a thin metal bar is visible around the top of the gum. Dentures are made that can fit onto this bar. Ramus-frame implants also can stabilize weak jaws and help to prevent them from fracturing.
This type of implant also is known as a plate-form implant. It is a type of endosseous implant (placed in the bone), but it is used less frequently than a root-form implant. Blade-form implants are flat rectangles of metal with one or two metal prongs on one long side. A blade implant is placed in the jaw so that the prong(s) stick out into the mouth. The prongs can support crowns or bridges.
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