Would I have to have tongue applicator first before I use invisalgin?

A. Tongue thrust is a difficult case to treat as the tongue is a very strong muscle and very difficult to control. Tongue beads can be fitted during orthodontic treatment with fixed braces and also added onto your removable retainers to try and stop or at least minimise the tongue habit. But you have to be aware that there is still a small risk it can relapse over time even if not fully. I would recommend a consultation with a dentist that offers different types of orthodontic treatments.