I'm almost done w/ invisalign. after this, dentist said i choose a permanent or overnight retainer. what are pros/cons of each & any recommendations?

Either will do: Permanent - no discipline but difficult to keep teeth really clean. Overnight-removable -you are responsible to wear it and not lose it.

See an orthodontist: Once the teeth are moved orthodontically, they won't stay there without a retainer. This is why wearing a proper retainer is necessary. With a wrong retainer just be prepared to go through treatment again. After active orthodontics, wearing a retainer 24/7 is the only way to keep teeth from moving. See an orthodontist-specialist who is in expert in this field for second opinion.

Overnight retainer: I prefer the overnight style retainer for my patients. While you do gave to remember to wear them, they come out so you can brush and floss your teeth properly. A "permanent" retainer is a wire bonded onto the backside of the teeth. They trap food and interfere with brushing and flossing and with out proper care can lead to periodontal problems.

Get overnight: better retention, easier to wear-- but wear more than just for sleep. We'd say from about 4-5PM-7AM (with taking out for dinner)

Retention: Despite all the hype, clear aligners only produce about half the tooth movement that braces can produce. Therefore when treatment completed root position is not as well refined, meaning greater post-treatment instability. Add to that the well documented fact that Dentists do not do Orthodontic Treatment to the same level as Orthodontists. Use removable retainers at least 14 hrs/day, every day.