This stiffness can also be caused by an injection. If it was your lower teeth that were prepared for the crown, then the lower injection can lead to a condition called trismus.
Trismus is a muscle injury as a result of the injection path of the needle. Trismus symptoms are much like TMD symptoms. It might feel like your jaw muscle has a Charley horse.
I would treat this the same way you would treat a muscle injury. Read my article about how to treat TMD. The main idea is to let the muscle relax and heal by eating soft foods and using pain killers that are anti-inflammatory in nature.
Your symptoms should eventually go away but be aware that you’re probably a teeth grinder — teeth grinders have muscles that are already fatigued and damaged from overuse, making them much more prone to conditions like trismus. I see teeth grinders get this condition much more frequently.
Things do take a long time at dental schools, but they usually get done very well because of the supervision of expert faculty.
I’m not sure why you had two long crown prep appointments because usually it just takes one, however, I believe your pain is from being open for so long, not the procedures themselves.
Ask your dentist about trismus. He or she will be happy to talk to you about it and keep the time your mouth is open during appointments to a minimum.
Mark Burhenne DDS