Because we use the term “temporary” in reference to the short term crowns we use during treatment the temptation is to call their longer lasting counterparts “permanent” crowns.
But, is that really accurate? Is anything we do for a patient (except an extraction) permanent?
I don't think so. And, if we refer to “permanent fillings” and “permanent crowns” then we are setting the patient up for disappointment.
I'm not sure whether it is true or an urban myth, but someone told me about a patient who was disappointed because his gold crown had failed after 40 years. The patient supposedly said when he was told it had failed “But the dentist told me it was permanent.”
Personally I use the term “real crowns”, never “permanent” ones.