Enhanced emigration of crevicular leukocytes mediated by factors in human dental plaque

The present investigation was performed to study whether a filtrate from human dental plaque when applied topically to the gingival margin enhances gingivitis. Four‐day‐old plaque was sampled from 20 dental students. The plaque samples were pooled, suspended in NaCl, homogenized, centrifuged and filtered. The capacity of the plaque filtrate to attract neutrophil leukocytes was determined by measuring the number of leukocytes (a) which migrated into wound chambers containing the filtrate and (b) which could be sampled from the gingival crevices of dogs and monkeys after repeated topical application of the filtrate to the gingival margin. Gingivitis was assessed by gingival exudate measurements. The results showed that substances present in human dental plaque are highly chemotactic for neutrophil leukocytes. The filtrate stimulated enhanced emigration of leukocytes into the gingival crevices and enhanced gingival exudation. The observations indicate that a plaque filtrate may enhance vascular and cellular changes similar to those seen in incipient gingivitis.