Toothache under a crown: does the crown have to come off

Patients worry that an expensive crown will be wasted. The canal can often be treated straight through it — but that is not always the better option.

Technically, access is made through the chewing surface of the crown: the dentist drills a small opening, treats the canal and then seals the access with a filling. This works with both metal-ceramic and zirconia crowns.

When this makes sense

If the crown fits tightly, there is no decay underneath and the tooth itself is sound, keeping the existing work is more sensible than cutting it off and redoing everything. One condition matters: the access must be sealed tightly afterwards, otherwise infection returns by the same route the dentist used.

When the crown is better removed

• the margins are not tight and decay is developing underneath
• the tooth is badly damaged and needs a new foundation for the crown
• the crown is due to be replaced anyway
• the opening does not give enough view and access to the canals

Worth keeping in mind

An opening in a crown compromises its integrity, even if only slightly. Access through zirconia is harder than through metal-ceramic: the material is tough, and the work takes time and specific burs. So the decision is always weighed: what costs the patient more in the long run — a carefully restored access or a new crown.

Above all: pain under a crown is not something to wait out. The sooner we look and take an X-ray, the better the chances of getting away lightly.