Why Doesn't my Vacuum-Formed Retainer Cover my Molars?

There is a major risk wearing a vacuum formed retainer that does not cover the biting surfaces of all of your teeth. The most significant risk is having the teeth hyper erupt which is exactly what sounds like happened to yours. You need to immediately return to the doctor who treated your case and express your concerns. Good luck!

It could be that when you finished treatment the back molars were not touching. In that case your Orthodontist may have left out the molars so they could super erupt in to place.

Now, it looks as though that situation is reversed. You are now hitting the molars before the rest of the teeth. There are more than one way to remedy the situation. Please check with your Orthodontist. After the problem is handled  make sure your vacuum formed retainer covers all the teeth.

The reason Invisalign covers all of the teeth rather than just the crooked front ones is that molar extrusion can occur.  You really should go back to the orthodontist and have him/her make you a full coverage set or a type of retainer that does not cover any teeth at all.  Hopefully things will settle back down.