Burnished versus nonburnished application of citric acid to human diseased root surfaces: the effect of time and method of application.

Citric acid (pH = 1) was applied passively or by vigorous burnishing for 3 or 5 minutes to diseased human root surfaces following root planning in vitro. Control surfaces were similarly treated with saline only. Teeth were fixed in glutaraldehyde, dehydrated, freeze-dried, and sputter coated with gold for scanning electron microscopic viewing.