Is it possible to correct my posterior crossbite with Invisalign?

Invisalign is an orthodontic appliance (it moves teeth). The reason you have a posterior crossbite is because your upper dental arch (maxillary bone) is underdeveloped; therefore, you require an orthopedic appliance to further develop your jaw bone NOT an orthodontic appliance. There are some very good orthopedic appliances designed for correcting adult posterior crossbites; among my favorites is the DNA appliance. You would need to wear the DNA appliance 12-17 hrs/day for 6-12 months to correct your posterior crossbite.Good luck!

I have corrected several Cross bites with Invisalign but ALL orthodontic and aligners will struggle with correcting posterior cross bites. Your age is very important as the bone hardens with time. I have used Propel to ADD to Invisalign to more efficiently move difficult teeth and wouldn't do your treatment with out Propel.  There are a few fixed devices that may improve the positions prior to straightening so get several opinions and at least one from someone experience using Propel.