What Is a Zirconia Bridge? Fixed Prosthesis for Missing Teeth

Where one or several teeth are missing, closing the gap is not merely a matter of appearance. If a gap is left, neighbouring teeth tilt into it over time, teeth in the opposing jaw over-erupt and the bite relationship is disturbed. One of the established ways of closing such a gap is a fixed bridge. In this article we look at what a zirconia bridge is, when it comes into consideration, how it differs from an implant and how it is cared for.

What Is a Bridge?

A bridge is a fixed prosthesis that closes the gap of a missing tooth by drawing support from the teeth on either side. The teeth flanking the gap (abutment teeth) are reduced to a certain extent and crowned; the pontic replacing the missing tooth is attached to these crowns. The structure is made as a single piece and fixed in place with cement; the patient cannot remove it.

A zirconia bridge is the version in which the framework of this structure is produced from zirconium dioxide. Being metal-free allows it to transmit light more like a natural tooth, which helps achieve a more natural appearance particularly in the front region. For the general properties of the material see our zirconia crown page.

When Does It Come Into Consideration?

• Where one or several adjacent teeth are missing and sound abutment teeth are present on either side of the gap
• Where the abutment teeth already need large fillings, root canal treatment or crowns — since these teeth will be crowned, additional tissue loss stays limited
• Where bone volume is insufficient for an implant and grafting is not preferred
• In systemic conditions where implant surgery is not appropriate
• Where a fixed solution is needed in a shorter time — implants require a healing period

Bridge or Implant?

The fundamental difference between the two options is where support comes from: a bridge draws support from the neighbouring teeth, an implant from the jawbone. This difference has two important consequences.

First, a bridge requires the neighbouring teeth to be reduced. If those teeth are sound and have never been treated, healthy tissue is lost, and this is irreversible. Second, the jawbone in the region of the missing tooth is not stimulated by a bridge; bone resorption can continue beneath it. An implant, by stimulating bone with chewing forces, slows this process.

On the other hand a bridge is completed in a shorter time, requires no surgery and is unaffected by insufficient bone. The choice is made by assessing the condition of the abutment teeth, bone volume, general health and expectations together. For details of the comparison see our article on implant or bridge, and for the implant side our implant treatment page.

Treatment Stages

1. Assessment

The soundness of the abutment teeth, their root condition and supporting bone are examined radiographically. Gum health and the bite relationship are assessed, and any decay or inflammatory process is treated first. Whether the abutment teeth are able to carry the bridge is the main question at this stage.

2. Preparing the Teeth

The abutment teeth are reduced to a certain extent to make room for the crowns that will sit over them. The procedure is carried out under local anaesthesia. For details see our article on how dental crowns are made.

3. Impression and Temporary Bridge

The mouth is recorded with a conventional impression or a digital scan. A temporary bridge is fitted until the definitive one is ready; this both protects the prepared teeth and maintains aesthetics and chewing function.

4. Try-In and Cementation

The fit, colour and bite of the bridge produced in the laboratory are checked in the mouth. Once any necessary adjustments are made, the bridge is cemented. The bite is checked again after cementation — a high spot causes force to concentrate in a single area.

What Determines Its Lifespan

How long a bridge continues to function cannot be expressed as a single number; what is decisive is not the material but the condition of the teeth beneath it and the surrounding tissue:

• Health of the abutment teeth: Decay developing at the crown margin can require replacement even if there is nothing wrong with the bridge.
• Gum health: The relationship between the crown margin and the gum directly affects the long-term result; gum recession can expose the margin area.
• Oral hygiene: The area beneath the pontic is the most commonly missed region in daily cleaning.
• Bite fit and grinding: Excessive forces increase load on both the bridge and the abutment teeth; with a grinding habit a night guard may come into consideration.
• Quality of the clinical and laboratory stages: Impression accuracy and marginal fit are the technical foundation determining long-term behaviour.

How Is It Cared For?

Caring for a bridge requires one step more than ordinary brushing, because regular floss does not pass beneath the pontic:

• Superfloss or a floss threader is used for cleaning beneath the bridge.
• Interdental brushes make it easier to reach the margin areas of the abutment teeth.
• A water flosser can be used as an adjunct where the dentist recommends it.
• Having tartar cleaning at regular intervals keeps accumulation at the crown margin under control.
• At check-ups the marginal fit and bite of the bridge are reassessed.

Zirconia or Other Materials?

A bridge framework can also be produced with metal-ceramic or other all-ceramic systems. What stands out about zirconia is that it contains no metal and transmits light; with metal-supported systems a grey line can become visible at the margin if the gum recedes. That said, one material is not suitable for every case: the length of the gap, the chewing forces in the region and aesthetic expectations all affect the choice. For a material comparison see our articles on zirconia or porcelain laminate and our porcelain crown page, and for the care side zirconia crown lifespan and care.

Summary

A zirconia bridge is a metal-free fixed prosthesis that closes the gap of a missing tooth by drawing support from the teeth on either side. Requiring no surgery and being completed in a shorter time are its notable advantages; on the other hand it requires reduction of the neighbouring teeth and does not stimulate the bone in the gap region. The main factor determining the long-term result is not the material but the health of the abutment teeth, the condition of the gums and regular cleaning beneath the bridge.

This article is for general information. Determining the option that suits your missing tooth requires clinical examination and radiological assessment.