Abutment Definition
An abutment is one of the three primary components of a dental implant, and is designed to connect the implant fixture, which is a titanium post that is placed in the jawbone and which acts as the artificial root of the tooth, and the implant crown, which is a fabricated dental restoration that is designed to look and function like your natural tooth. Prior to placement of the abutment and implant crown, it will take several months for the implant fixture to fully fuse with the surrounding jawbone. Once this process (known as osseointegration) is complete, the titanium post will be ready to act as the new artificial root of the implant crown.
At this point, the abutment, which is typically made of titanium, Zirconia, stainless steel or gold is used to connect the new crown to the dental implant. Ceramic abutments are also sometimes used, as they provide a more natural look, however this material type is not as strong as the other materials, so it is generally discouraged, especially if the tooth being replaced is in the posterior molar areas where chewing forces are stronger. While there are several different approaches, most commonly the implant and the abutment are joined together with a small screw that goes through the abutment’s center, which creates enough strength and stability for the implant to adequately bear the pressure and force that comes from biting and chewing.
Prefabricated of Custom-Made Abutments
Depending on your specific needs, your abutment may be prefabricated or custom made. Factors that can determine which type of abutment best meets your needs include how the abutment is being placed (dental cement, lag screws, or special retainers), where the implant is being placed, and whether the abutment is being used for a crown, fixed bridge, or removable denture. If you require a custom-made abutment, it will be necessary to take an impression of the implant top to ensure it fits with the surrounding teeth and gingiva. Custom-made abutments may also be used when the crown and abutment are designed as one piece, compared to a two- or three-piece implant.
One, Two, and Three-Piece Implants
The design of the abutment can vary depending on whether the patient is receiving a one, two, or three-piece dental implant. For one-piece implants, the implant and abutment are fused together and the implant can be placed in one surgical procedure. This approach, when a viable option, can be preferable as it requires fewer procedures and is more cost affordable. In most cases, however, patients will receive a two- or three-piece implant. In a two-piece implant, the abutment is placed using a screw, cement, or is cold welded in order to decrease microbial leakage, which can cause the implant to fail. For three-piece implants, the abutment is typically fixed with a screw butt joint that is tightened with a torque wrench, resulting in greater stability and a decreased chance of complications developing. While this approach requires more procedures and tends to be costlier, the benefit is that the abutment, implant fixture and crown have improved stability.