A dental bridge is a fixed prosthetic device designed to replace one or more missing teeth by spanning the gap between them, maintaining the alignment of surrounding teeth and restoring function. The structure consists of two main parts: the pontic, the artificial tooth that fills the empty space, and the abutments, the supporting structures at either end of the gap. Abutments can be natural teeth or dental implants. The method used to secure the pontic determines how the bridge stays in place and withstands the significant forces generated during chewing and speaking.
The Mechanics of Traditional Bridge Support
The most common method secures the bridge using the two natural teeth adjacent to the missing space as anchors. This requires preparing these abutment teeth by carefully reshaping them. A dentist reduces the outer layer of enamel to create space for a crown to fit without appearing bulky. This preparation is irreversible, meaning the prepared teeth will always require a protective restoration.
Once prepared, custom-made dental crowns are fabricated to fit precisely over the abutment teeth. These two crowns are permanently fused to the pontic, forming a single unit. The appliance is then cemented onto the prepared natural teeth using a high-strength dental luting agent. Modern materials, such as resin-based cements, are chosen for their ability to achieve a strong bond between the crown and the underlying tooth structure. The cement creates a tight seal that resists biting forces and prevents the ingress of bacteria, keeping the bridge stable.
Alternative Retention Techniques
Not all bridges rely on full-coverage crowns. The Maryland bridge, also known as a resin-bonded bridge, offers an alternative using a metal or porcelain framework. Instead of reducing the entire abutment tooth for a crown, the Maryland bridge features one or two metal or ceramic “wings” bonded to the tongue-side surface of the adjacent teeth.
Retention comes from a strong composite resin cement that adheres the wings directly to the tooth enamel. Because it avoids aggressive tooth reduction, the Maryland bridge is a minimally invasive option, though it is reserved for replacing front teeth where chewing forces are lighter. Another variation is the cantilever bridge, secured by an abutment on only one side of the missing tooth gap. This design places significant mechanical stress on the singular anchoring tooth, making it reserved for areas with minimal biting pressure.
Implant-Based Stability
A different approach to bridge retention uses dental implants as abutments instead of natural teeth. An implant-supported bridge is anchored by titanium posts surgically placed directly into the jawbone. Stability is achieved through osseointegration, a biological process where bone tissue fuses directly onto the titanium post. This fusion creates a fixed foundation that mimics the stability of a natural tooth root.
After osseointegration is complete, which typically takes several months, the bridge is attached to these implanted posts. The connection is made either by screwing the bridge directly into the implants or by cementing it onto an intermediate component called an abutment. This mechanism removes reliance on neighboring natural teeth, preserving their structure. The resulting stability allows the bridge to withstand heavy chewing forces without placing strain on surrounding dentition.
Maintaining the Bridge’s Secure Fit
The security of any bridge depends on consistent maintenance. Abutment teeth supporting a traditional bridge remain susceptible to decay, particularly at the margins where the crown meets the tooth structure. If decay compromises the abutment tooth, the secure fit of the crown and the entire bridge can be lost.
Patients must use specialized tools, such as floss threaders or interdental brushes, to clean beneath the pontic where a regular toothbrush cannot reach. Avoiding excessive pressure, such as chewing on hard candies, ice, or sticky foods, helps prevent forces that could weaken the cement bond or fracture the abutment teeth. Regular dental check-ups are important, allowing a professional to monitor the integrity of the margins and the bond, identifying potential issues before the bridge becomes loose.