An abutment is an element that connects two things. The term is used in engineering to refer to the supports on either end of a bridge; in dentistry, the use is similar. In dentistry, the elements that are connected can be teeth, or they can be implants. Two teeth, called the “abutment teeth,” support a fixed bridge or partial removable dentures. Abutment implants can be used to attach a bridge, a crown, or a removable denture to a dental implant. A dental implant is a small cylindrical piece of metal that is implanted into the jaw and that gradually integrates into the bone as the bone heals around it, in a process called “osseointegration.” Dental implant abutments are placed as close to parallel in the mouth as possible; combined with their integration with the bone, this creates a remarkably stable support system for dental prosthetics.
Prosthetic implant abutments connect dental prosthetics, like bridges and crowns, to dental implants. Prosthetic implant abutments can be made from a variety of materials, including ceramic, titanium, surgical-grade stainless steel, or gold. The material used for the implant abutment depends on the location in the mouth and the needs and desires of the patient. For example, when placing prosthetics on the molars, dentists may prefer to use a strong metal prosthetic abutment so that the prosthetic will be able to effectively support the forces of chewing; these forces are considerably greater in the molars than in the other teeth. On the other hand, when placing a prosthetic crown on an abutment that is closer to the front of the mouth, a ceramic abutment can help the crown appear more lifelike, but ceramic abutments are also more fragile than metal abutments. These decisions must take into consideration factors like compressive strength and aesthetics, as well as cost. Abutments can be particularly helpful when implants are placed at an angle different from the roots of the adjacent teeth, which is sometimes necessary when the supporting bone is thinned or weakened. An angled implant can often provide better support than a vertical one; the abutment that rests on top of the implant is then placed at an angle on the implant, so that the prosthetic is parallel with the rest of the teeth. This is another advantage implants can provide: they allow prosthodontists to use existing, healthy bone as efficiently as possible to support the greatest amount of mechanical function for the prosthetic that the implant will support.
Abutments are usually fixed onto implants with cement or with screws. These specialized dental screws are affixed with a professionally engineered dental torque wrench that allows the prosthodontist to adjust the screw’s torque to factor in the possibility of the screws loosening when exposed to the forces of biting and chewing. With some implants, the abutment is cold welded onto the implant or attached with a machine taper called a Morse taper. The Morse taper has proven to be one of the most effective ways to attach an abutment, providing a secure and stable foundation. Implants can fail if bacteria is able to seep between the implant and the abutment, which leads to inflammation and eventual degradation of the bone. Morse taper abutments provide an excellent seal, and the implant survival rate with Morse tapers approaches 99%.
What is a Dental Implant Abutment?