A fixed dental bridge is a prosthetic device designed to replace one or more missing teeth by spanning the empty space. This restorative option is a single, cohesive unit custom-made in a dental laboratory to restore function and appearance. The appliance is permanently cemented onto the natural teeth or dental implants adjacent to the gap. Unlike a removable partial denture, the fixed bridge remains securely in the mouth, providing a stable solution for chewing and speaking. The success and longevity of this restoration depend on the precise fit and structural integrity of its three main components.
The Supporting Components (Abutments)
The abutment is the anchor component of the fixed bridge, referring to the natural tooth or dental implant that provides support for the entire prosthesis. Abutment teeth must be healthy and strong enough to bear the additional forces transferred from the replacement tooth during chewing. For a traditional bridge, the teeth on either side of the missing space are designated as the abutment teeth.
To allow the bridge to fit, the abutment teeth must undergo preparation, where the dentist reduces the natural tooth structure. This reduction creates the necessary space and contours for the retainer to be cemented permanently. The retainer is the cap-like crown portion of the bridge designed to fit securely over the prepared abutment tooth.
The retainer crown is fabricated as an integral part of the final bridge unit, providing the secure foundation for the replacement tooth. Proper preparation and a well-fitting retainer are paramount, as the abutments distribute the functional load into the jawbone and surrounding tissues. If the abutment teeth are not prepared correctly, the long-term stability of the bridge can be compromised.
The Replacement Unit (Pontics)
The pontic is the artificial tooth component of the fixed bridge, replacing the missing tooth or teeth. It is the visible, functional part of the restoration that sits over the edentulous ridge, the gum line where the natural tooth root was located. The pontic restores the patient’s ability to chew and speak while providing an aesthetically pleasing replacement.
Pontic design focuses heavily on hygiene access to prevent plaque buildup underneath the artificial tooth. A common shape is the modified ridge lap pontic, which is convex on the tissue-facing side, contacting the soft tissue minimally. This contouring allows for effective cleaning with dental floss or special hygiene tools.
The ovate pontic is often used in highly visible areas because it appears to emerge naturally from the gum tissue. This design requires a slight depression in the edentulous ridge tissue for the convex underside to rest within it. Designs ensuring minimal contact or convex contours are preferred, as complex, concave surfaces trap food debris and are challenging to keep clean.
The Structural Link (Connectors)
The connector is the structural element that joins the retainer crown to the pontic, forming the complete, single unit of the fixed bridge. This junction is responsible for the overall strength and rigidity of the prosthesis, ensuring the entire structure moves as one under the forces of mastication. In metal-based bridges, this connection is often established through soldering.
The most common design is the rigid connector, which creates a solid, immovable union between the abutment retainer and the pontic. Rigid connectors are preferred because they efficiently transfer forces to the supporting abutments, stabilizing the bridge.
In certain complex cases, such as those involving a long span or a pier abutment, a non-rigid connector may be used. A non-rigid connector allows for a minute degree of movement between the components, helping to relieve stress on the abutment teeth by distributing the load differently. This specialized link is typically fabricated as a key-and-keyway system.