While they may have been called this a Dental Bidirectional Key back in the 18th century I prefer to call this primitive tool a whole lot of %$#**%## pain. While the dentist has this little puppy clamped down on your tooth you just might want to have your will written out just in case you go into Cardiogenic shock from the pain. Gives a whole new meaning to the expression, “SAY AHHHHHHHHHHH…”