is it True that If I try to Expand with Invisalign that I Run the Risk of the Alignment Reverting Back?

Whether or not invisalign is the treatment of choice for expansion depends on the type of expansion required.  If the teeth are tipped inward, this requires dental correction which invisalign can usually achieve effectively.  However, if the problem is due to lack of proper jaw bone growh, then this is an orthopedic problem which requires orthopedic expansion with custom-designed expansion appliances specific for the individual patient and would not be suitable for invisalign.  Attempting to correct an orthopedic problem with invisalign will only result in temporary tipping out of the teeth which will not be stable long-term.

If there is major expansion to be done, then you are better off with traditional orthodontics using palatal expanders. If there is only minor expansion, then invisalign can be quite effective. You MUST wear your retainers, however, religiously every night in order to prevent a relapse.