Trichomonas tenax

[tēnăks′]
n.
  1. A protozoan that lives as a commensal in the mouth; it is found especially in tartar around the teeth or in defects of carious teeth.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.