A prosthesis for insertion into a body passage is disclosed. Efficient use is made of keystrokes on the data-enabled telephone. A charge trapping structure, such as a layer of silicon nitride, is formed over the channel region. The decreased amount gas reflected back toward the shooter decreases the amount of noise the shooter hears. Thereafter, the first mold 7 is moved along an arrow A direction relative to the second mold 8 fixed to an anchor block, by which the titanium material 20 substantially immovably retained in the groove 13 of the first mold 7 is bent and pushed into a through hole 24 of the second mold 8 by the first guide portion 15, thus being plastically deformed.