A dental bridge is a fixed prosthetic appliance designed to replace one or more missing teeth. This restoration consists of artificial teeth, known as pontics, and crowns that anchor the unit. These crowns are cemented onto the natural adjacent teeth, called abutment teeth. The bridge restores chewing function, improves speech clarity, and maintains aesthetics. It also prevents surrounding teeth from shifting into the empty space, preserving the proper alignment of the bite.
Preparing the Abutment Teeth
The preparation of the natural abutment teeth is the first step for a traditional bridge. The dentist reshapes these teeth by removing a precise amount of enamel and dentin so the crown can fit without adding bulk or interfering with the patient’s bite. This reduction creates a specific shape for retention and resistance.
The process typically requires removing 1 to 2 millimeters of tooth structure from all surfaces, depending on the bridge material. This filing creates a distinct “finish line” or margin near the gum line where the crown will terminate. This detail must be accurately captured for the laboratory technicians.
Following preparation, the dentist places a temporary bridge over the area. This provisional restoration protects the exposed, sensitive dentin from temperature changes and bacteria while the permanent bridge is fabricated. The temporary bridge also maintains the proper spacing of surrounding teeth, preventing them from drifting.
Taking Impressions and Digital Scans
After the abutment teeth are prepared, the exact dimensions of the mouth must be captured to serve as the blueprint for the laboratory. Traditionally, this involved taking a physical impression using a putty-like material placed in a tray. While effective, this method can be messy and uncomfortable for the patient.
Modern dentistry often utilizes digital intraoral scanners to create a virtual, three-dimensional model of the mouth. A small wand is moved over the prepared teeth, the gap, and the opposing arch, capturing thousands of data points per second. This process is faster, more comfortable, and minimizes the risk of distortion associated with physical materials.
The highly accurate digital data is transmitted immediately to the dental laboratory. The virtual model allows the lab technician to begin the design process using Computer-Aided Design (CAD) software. Capturing the precise relationship between the prepared teeth and the patient’s bite ensures the final bridge fits perfectly.
The Laboratory Fabrication Process
The dental laboratory transforms the data from the dental office into the final bridge. A skilled technician uses the digital file or physical model to design the restoration, matching the shape, size, and color of the patient’s existing teeth. The choice of material is important, with options including porcelain fused to a metal alloy (PFM), high-strength ceramics like zirconia, or glass-ceramics such as lithium disilicate (e.max).
For all-ceramic restorations, the design is transferred to a Computer-Aided Manufacturing (CAM) unit, often a high-precision milling machine. This equipment carves the bridge out of a solid block of ceramic material, ensuring accuracy and a uniform structure. CAD/CAM technology allows for the rapid and predictable production of restorations that fit precisely.
When aesthetics are paramount, the technician applies layers of porcelain powder onto the milled or metal framework. Each layer is sculpted to mimic the natural tooth’s translucency and texture before being fired in a specialized oven. This layering achieves a lifelike appearance by incorporating subtle color variations and surface characteristics.
The laboratory process may also involve 3D printing to create detailed resin models of the patient’s jaw. The technician uses these models to verify the fit of the designed bridge before final processing. The ultimate goal is a restoration that is structurally sound and aesthetically indistinguishable from adjacent natural teeth.
Final Fitting and Cementation
The final stage involves securing the permanent bridge during a second appointment. The temporary bridge is removed, and the prepared abutment teeth are thoroughly cleaned for bonding. The permanent bridge is then “tried in” to check its passive fit, ensuring it slides smoothly onto the prepared teeth without tension.
The dentist evaluates the bridge’s aesthetics, confirming the shade and contour blend seamlessly with surrounding teeth. The patient’s bite, or occlusion, is checked using articulating paper, which marks any high spots. Small adjustments are made until the bite force is evenly distributed, preventing discomfort or damage.
Once the fit and bite are finalized, the abutment teeth are conditioned, and specialized dental cement is applied to the inside of the crowns. The bridge is seated firmly, and the cement is allowed to set. For certain ceramic materials, a resin cement is used, often requiring a light-curing unit to instantly secure the bond.