Use of the electric pulp tester and the apex locator during assessments of pulp vitality and root length determination involves bacterial cross-contamination of the metal surfaces of the probe tip and lip clip inserts which contact the oral hard and soft tissues. Reuse of these endodontic aids necessitates the sterilization or disinfection of the metal insert or the acquisition of extra attachments. A barrier technique that protects the electric pulp tester probe tip and the apex locator lip clip from bacterial contamination and employs the principle of electric conductive bridging is presented.