Why a zirconia bridge is not always the right choice

Patients sometimes hear "we will not use zirconia here". The reason is usually not the material itself but the length of the span between supports.

A bridge rests on your own teeth or on implants, and the section between the supports hangs without support of its own. The longer that span, the greater the bending load on the structure during chewing.

Where the limit lies

A telling case is a four-unit bridge with only two supporting teeth and two suspended units between them. That span is already risky for zirconia: under a sudden load — biting on something hard, for instance — the structure can chip or crack.

This does not mean the material is poor. Zirconium dioxide is very hard, but hardness and the ability to flex are different properties. Where bending is involved, the safety margin runs out sooner than people expect.

What we suggest instead

• add a support — an implant, for example, to shorten the span
• choose a different structure with a metal framework where the load is higher
• split the work into two short bridges instead of one long one

The decision always follows the specific situation: how many supports there are, their condition, the bite and the patient’s chewing load. That is why the same material is the best choice in one case and something the dentist argues against in another.