The Abutment Definition
What is abutment in dentistry?
From a dental perspective abutment is a connective element. This idea of abutment is used in various contexts. Abutments are used in fixed bridges (i.e. abutment teeth being the teeth that support the bridge), as well as in partially removable dentures. And abutments are an essential part of dental implants, connecting the crown to the implant fixture.
With dental bridges abutments are formed so that the insertion path of the teeth involved are almost parallel to each other. In the case of partial dentures, abutments might incorporate connecting elements such as guide planes, re-contouring, and rest seats.
Implant abutments are also knowns as prosthetic implant abutments and are used to make the connection between the implant and the prothesis. The abutments are constructed from various materials such as gold, surgical stainless steel, and titanium. Ceramic abutments are sometimes used as well, and are especially effective when used to enhance ceramic crowns, allowing for a more realistic/natural appearance. However, it is necessary to use ceramic abutments with care since they do not have the kind of compressive strength of gold, titanium, and other metals. Most technicians are much more comfortable using prosthetic abutments that are metal, especially in the molar areas that are in the back of the mouth, because of the increased masticatory/force that is present.
Abutments are not always parallel to the longer axis of an implant. And it is used when an implant is inclined differently in relation to a possible prothesis. Most fixed dentures and crowns have a screw-retained or cemented fixation on the abutments.
Abutment in a three piece implant
In the case of a three piece implant an abutment is secured to the implant by a screw butt joint. This screw then has to be tightened with a dental torque wrench to a specific torque that has been predetermined, so as to avoid any loosening of the screw when chewing is taking place. Chewing often creates a kind of torque on the abutment that is counter-clockwise, which can then slowly cause loosening of the abutment. However, usually with correct torqueing of the abutment and with correct design of the screws being used, this can usually be prevented.
Abutment in a two piece implant
In the case of a two piece implant an abutment gets cold welded or morse tapered on to the implant. Colonization between an implant and an abutment can cause inflammation and/or bone loss. Microbial leakage can also result in inflammation and/or bone loss.
Abutment in a one piece implant
In the case of a one piece implant (also known as an OPI) what is knowns as a trans-mucosal abutment is integral to the functionality of the implant. This kind of implant typically uses immediate loading (which is a process where a crown in placed immediately following the placement of the implant). And, often a procedure known as flapless procedure is a part of the process for installation of a one piece implant.