Hello, I am ortho and I do indirect bonding... For vps clear i have used Memosil 2 from Heraeus, works good. The cheap choice is the hot glue gun I do not use it but I know doctors that use it (or have used it) and publish it. For sure you can find it in internet. I wrote an email to the doctor telling that I read the article and an "industrial material" was used to do the trays. The doctor told me that it was also used by doctors that do lingual ortho and it is ok because the material is the same as for pakaging the food (to seal the box).
I do not know legal ok? But it is used. When they use this system with the hot gun in the office, to remove easily the tray, after curing, the patient takes hot water ir order to soften the tray........
The Best way to do it today, and is the way I do it is with thermoforming sheets. Accuracy and easy to remove. I use two sheets, first one is flex sheet 1mm thikness ( I use erkoflex, from erkodent) and the second one is 0.5 mm hard sheet ( I use erkodur). I prefer to cover tube hooks etc with block material.
In the lab side takes more time with thermoforming sheets and obviously with the hot gun is easier takes 1 minute and is cheaper but is better with thermoforming sheets
