Abstract
The present paper reports the development of a method by which controlled pulp exposure can be achieved. Buccal cavities in teeth of adult monkeys were prepared by very slow intermittent cutting, using air as a coolant. During each intermission the electrical resistance of the tissues was measured by means of direct current. One electrode contacted the gingiva and the other was bur itself. The resistance values were related to observations in histological sections of the teeth. Under the conditions described, pulp exposure occurred at an electrical resistance of about 10 mega-ohm (M omega).