pivot tooth 名詞
  釘牙
  Piv·ot n.
  1. A fixed pin or short axis, on the end of which a wheel or other body turns.
  2. The end of a shaft or arbor which rests and turns in a support; as, the pivot of an arbor in a watch.
  3. Hence, figuratively: A turning point or condition; that on which important results depend; as, the pivot of an enterprise.
  4. Mil. The officer or soldier who simply turns in his place whike the company or line moves around him in wheeling; -- called also pivot man.
  Pivot bridge, a form of drawbridge in which one span, called the pivot span, turns about a central vertical axis.
  Pivot gun, a gun mounted on a pivot or revolving carriage, so as to turn in any direction.
  Pivot tooth Dentistry, an artificial crown attached to the root of a natural tooth by a pin or peg.