After Invisalign Treatment Will My Teeth Revert Back To Pre-Tx?

While teeth likely will not revert all the way back to where they started, if a person does not wear a retainer after orthodontics (Invisalign or brackets and wires) teeth will not stay put.  Once teeth are straight, the improved alignment should result in better chewing, so you should be able to eat as usual.

Chance of being worse that before?  Not likely.

As mentioned by all the doctors,  some type of retainer is needed  to prevent relapse of tooth movements.  There are many types of retainers including wires that can be attached to the back of the anterior teeth to hold them in place.  Also all types of plastic retainers can be worn at night to hold the teeth in place and these include very thin vivera retainers from Invisalign that must be replaced every so often.  Discuss this well with your dentist before you start and as you are getting ready to finish.  I tell all my patients that the only way to keep their teeth from moving sometime in their life is to wear some type of retainer for the rest of their life. 

Yes, your teeth will return to their original state once you are finished with your invisalign treatment unless you wear some type of retainer indefinitely.  This is true of any type of orthodontic treatment.  You should not be worse off than when you started as long as no permanent alteration of the shape of your teeth was made.  After your treatment is finished, there may be a few months of "settling in" of your teeth where your bite may not feel comfortable or natural, but you can still eat as usual without harming anything.  Just be sure to wear your retainers faithfully!