Should I be concerned about squeaking noise caused by dental crowns? (photo)

I have approx 20 porcelain dental crowns that were placed a couple years ago in the front of my mouth that “squeak” sometimes when stretching my mouth/ lips. I wear a night guard at night and take good care of them. It’s almost like they are close together and rub against each other due to pressure maybe. I’ve mentioned it to my dentist but they say it’s nothing to worry about and they are “well cemented on”. I worry a lot about my teeth please advise if something is wrong.