Abstract: Disclosed is a method and apparatus for electrically stimulating bone growth and tooth movement in the mouths of mammals. A positive electrode is placed on the gum surface adjacent the bone structure which is to be resorbed. A negative electrode is placed on the gum surface adjacent the bone tissue which is to be accreted or built up. A current source is connected, such that a small current flows between the electrodes, which has the effect of stimulating bone growth in a specific direction. In a preferred embodiment, the electrodes are placed on the gum surface adjacent a tooth, the positive electrode on the side towards which the tooth should move, and the negative on the side from which the tooth will move. Application of a small current to the electrodes will enhance the repositioning of the tooth in conjuction with normal orthodontic practices.

Abstract: An extrusion die is made by stretching a flexible membrane having one end held in a shape conforming to the input end of the die and the other end maintained in conformity with the desired profile of the part to be extruded.A fluid having hardening properties is applied to one surface of the distended membrane. Once the material has hardened, the flexible diaphragm is stripped away, and the resultant contour is coated with a material to form the contour of the die. This contour is cast in a shell, with appropriate heat and heat sensing elements, to form the die.