I have pressure sensitivity after biting an unpopped popcorn kernel.

First, dentist tried replacing existing filling/repairing cracks with
bonding material (tooth-colored material whatever it is).  This just had no
effect.

Now, he wants to put a temp crown on and have me wait six months to let it
'calm down'.  He also said we'd know in a week if a root canal is
necessary.

Is this a sound approach?