The cheapest and simplest solution to full edentulousness is the manufacturing of dentures, which lie on the mucosa of the teethless jaws, sticking to these, but still permitting a slight movement of the artificial teeth during mastication and possibly during speech as well, since besides the anatomical undercuts of the bone, there is nothing to stabilize them. The dentures of the upper jaw almost always are much more stable than the lower ones, due to the shape of the bone. When the dentures do not stay on the mucosa with satisfactory stability, this can be helped with denture-adhesives, or with the insertion of implants into the bone.