When only part of the tooth has erupted into the mouth, it can create a flap of gum tissue that easily holds food particles and debris and is a hotbed for bacteria. Pericoronitis also can occur around a wisdom tooth that has not erupted at all and is still under the gums.
Define futon: a usually cotton-filled mattress used on the floor or in a frame as a bed, couch, or chair a usually cotton-filled mattress used on the floor or in a frame as a bed, couch, or chairâ¦ See the full definition
Definition of trunnion. :  a pin or pivot on which something can be rotated or tilted; especially : either of two opposite gudgeons on which a cannon is swiveled.