A standard dental crown is a prosthetic cap designed to cover and restore a single damaged, decayed, or weakened tooth. The crown acts as a new outer surface, restoring the tooth’s shape, size, and strength. Because a crown is fabricated to fit one tooth precisely, it cannot physically extend to cover a second, separate tooth. Covering multiple adjacent teeth requires a different, multi-unit restoration.
What Is Used to Cover Multiple Teeth
Covering more than one tooth structure is accomplished using multi-unit restorations, such as a dental bridge or splinted crowns. A traditional dental bridge replaces one or more missing teeth by spanning the empty space. This structure consists of at least two crowns, called abutments, which are cemented onto the natural teeth or implants on either side of the gap.
The replacement tooth, known as a pontic, is fused between the abutment crowns, bridging the area where the tooth is absent. Bridges are classified by the total number of units; for example, a three-unit bridge has two abutment crowns and one pontic. This single piece is permanently bonded into place, relying on the anchor teeth for support.
Splinted crowns are used when no teeth are missing. This restoration involves two or more adjacent crowns that are permanently connected as a single unit. The purpose of splinting is to join weakened teeth to distribute biting forces across a greater surface area. This connection creates a rigid system that provides collective support for teeth that might otherwise be mobile or unstable.
Clinical Reasons for This Type of Restoration
A primary justification for a multi-unit restoration is replacing a missing tooth to maintain the integrity of the dental arch. When a tooth is lost, surrounding teeth begin to drift into the vacant space. The opposing tooth can also super-erupt, moving out of its socket, which disrupts bite alignment and can lead to temporomandibular joint (TMJ) disorders.
Dental bridges prevent this movement by filling the space with a pontic and anchoring the restoration firmly to adjacent teeth. Connecting crowns is also necessary for stabilization, often in cases of advanced gum disease (periodontitis). Periodontal disease causes bone loss around the roots, leading to increased tooth mobility.
By splinting crowns together, biting forces are shared across the connected units, reducing stress on any single compromised tooth. This helps stabilize the teeth and increases patient comfort during function. A bridge may also be recommended when a dental implant is not feasible due to insufficient bone volume or specific medical contraindications.
Long-Term Care and Maintenance
Maintaining a multi-unit restoration is more demanding than caring for a single crown. The connected nature of the units prevents standard dental floss from passing through the contact points. This allows plaque and food debris to accumulate in inaccessible areas, posing a risk of decay on the anchor teeth or inflammation beneath the pontic.
Specialized tools are necessary for proper hygiene because of these inaccessible areas. These tools are designed to clean the sides of the abutment teeth and the underside of the pontic.
Specialized Cleaning Tools
To clean under the restoration, patients must use specialized tools:
- Floss threaders, which feature a stiff end that can be threaded under the bridge.
- Superfloss, which has a stiff threader section followed by a spongy filament designed to clean the space between the pontic and the gum tissue.
- Interdental brushes, with small, tapered bristles designed to clean the underside of the bridge or between splinted crowns.
The longevity of the entire restoration depends directly on the health of the supporting abutment teeth. If an anchor tooth develops a cavity or gum disease, the entire bridge or splinted unit may fail and require replacement. This procedure is typically more costly and involved than replacing a single crown.
Regular professional checkups are important to monitor the abutment teeth for signs of decay or periodontal issues. The hygienist can perform a thorough cleaning, removing hardened plaque (calculus) from surfaces difficult to reach with home care tools. Patients must also avoid chewing overly hard or sticky foods, which can place undue stress on the restoration.