ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Ehma7jkbmSw.html Dental Arch Expansion with Pseudo Tongue Appliance. Works for upper and lower arch. 舌を模した歯列弓拡張器. A simple appliance to widen the narrow arch. It functions like the natural tongue, but it is much stronger than the tongue. It can widen the upper and lower arch in a rather natural approach.