materia alba

[mə-tîrē-ə ălbə]
n.
  1. A white cheeselike accumulation of food debris, microorganisms, desquamated epithelial cells, and blood cells deposited around the teeth at the gumline.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.