If a crown can come off during a dental impression, there is a problem and it is a GOOD thing to get it removed (it means it is leaking/decaying underneath). The cement or bond SHOULD be strong enough to eat sticky food AND take dental impressions.
From your pictures posted it appears that you may have had your 3rd molars, or wisdom teeth, removed. This isn't usually considered an extraction for orthodontic reasons as most young adults have their wisdom teeth removed. You were in a crossbite before and you are still in a crossbite. You T...
Ideally by age 8 you would have had your jaw expanded when it was very easy. As an adult the best approach is a removable functional appliance to grow your maxilla orthopedically.
This will eliminate dark buccal corridors and make room for all of your teeth. You are 19 and deep nasal labial gr...