What are the treatment options for decay found under a crown?

Depends: Depends on severity. Maybe able to move decay and replace crown, but may need to extract tooth if severe.

Remove crown: Remove decay,root canal,replace tooth or place bridge. All the best.

Several-see a dentist: If it's extremely early on and accessible, a filling can sometimes be placed to repair the decay. More likely, you will need the decay removed, and a new crown to be placed. Sometimes the cavity has already gone deeper, and a root canal could be needed as well... In the worst case, the cavity has progressed to an area that cannot be treated, and an implant could be indicated... See a dentist...

A crown: The crown must be removed in order to access the decay. Once the decay is removed, the remaining structure will be evaluated for stability. If there is enough sound tooth structure, a new crown can be fabricated.