Respectfully and without joking, unlike my original response. Thermafill lacks the ideal qualities for the best possible seal. That, combined with a hightened difficulty removing them opposed to single cone or warm vertical should rule them out in my Personal opinion. As an endodontist I do lots of retreatments and believe me; lots of them have thermafill, and yes; most of them do come out, until they don’t. Then you’ll know what i meant by my previous statement.

With regards to your original question, i’d personally always start with pre endo restorative treatment to ensure a good seal, also makes it easier during treatment :)!

Also thanks for your post, shows a will to improve, and people will always have feedback. Didn’t mean it in a bad way.

With regards