Patients that are missing teeth may be considering dental implants to restore their smiles. Implants have three components which together, create a strong construction that looks and functions like a normal set of teeth. One of the components is the implant abutment which will be the focus of this discussion.
Dental Implant Abutment: Overview
Implant abutments are artificial devices that act as the connector between the dental implant and the restorative bridge, crown, or removable denture. Implant abutments come in two classes: prefabricated and custom made.
Prefabricated Abutments: Manufactured in a variety of sizes, prefabricated or stock implant abutments are often delivered along with the dental implants. The correct abutment for the case is selected from the range of sizes and shapes.
Stock abutments are made from a variety of materials including zirconium, gold, stainless steel, and titanium.
- Titanium: Because of their strength and biocompatibility, titanium implant abutments are commonly used with any type of prosthetic restoration. Titanium is also ideal when placing in the posterior molar because of the increased chewing forces associated with these areas.
- Zirconium: A more modern option, zirconium abutments are an increasingly popular option due to their aesthetics. Zirconium abutments avoid the issue of matching to the shade of the adjacent teeth while hiding the darker metal abutment color.
- Other Materials: Gold and stainless steel are other alternative materials used in implant abutments. While less frequently used, there are cases where these may be appropriate and successful.
- Custom Made Abutments: Using an impression of the implant and adjacent teeth, custom made implant abutments are fabricated in a dental laboratory. The clinical application will dictate the shape, size, and material used.
Most any type of abutment can be custom made at a dental lab including those with smooth surfaces, with threaded holes, and various types of special anchoring systems for removable dentures.
Selecting the Right Implant Abutment
Several considerations are involved when the dentist is selecting the abutment including:
The type of prosthesis being used: removable denture, fixed bridge, or crown.
How the restoration will attach to the abutment: dental cement, lag-screws, or using special retainers.
Implant position inside the mouth: typically, larger abutments are positioned in the rear of the mouth because of the increased masticatory forces in these areas.
Securing the Implant Abutment
After the correct abutment is selected for the patient, consideration must be given to how the abutment will be secured.
- Dental Cement: Ideal when the artificial abutment has a smooth surface, the restoration is adhered to the abutment with dental cement. Cement fixes the crown or bridge in place like natural teeth. While cement can be advantageous in its aesthetics, one potential drawback is that excess cement could lead to gum irritation.
- Lag-Screws: For restorations involving abutments with threaded holes in their middle. Lag-screws traverse the dental crown and attach to the threaded hole to secure the crown in place. The main advantage of screw retained implant abutments are their ease of maintenance and replacement in the event of prosthetic failure.
- Special Retainers: Retain dentures using a male-adapter on the implant to attach to a female-adapter in the denture. These allow movement of the denture but adequate retention to improve comfort compared to traditional dentures.