The phenomenon of leukopedesis in gingival and periodontal tissues was measured by counting the number of orogranulocytes migrating into the mouth during repeated intervals of 30 seconds. Measurements were carried out with a computerized electronic cell grading system and classified as a non-subjective laboratory routine for indexing oral inflammation. For orogranulocytic migratory rate (OMR) readings above 1.2 X 106/30 sec, a minimum of three determinations is required for reliability. Single readings suffice for OMR's below 0.5 X 106/30 sec, which indicates that the system is suitable for mass screening purposes. © 1969, SAGE Publications. All rights reserved.
