Neutrophil chemotactic activity elaborated by human dental plaque

In the present investigation an in vivo method is described for studying the chemotactic activity elaborated by factors in human dental plaque. Plaque was sampled from the buccal and lingual surfaces of teeth from dental students, who had refrained from mechanical tooth cleansing during one 4 and one 8 day period. The plaque samples were suspended in 0.15 M NaCl, homogenized, and centrifuged at 12,100 × g for 30 minutes at 4°C. The plaque supernatant was then separated from the cellular pellet and sterile filtered through a 0.45 μ Millipore filter. The chemotactic activity elaborated by the filtrates was examined in (i) Boyden's in vitro chamber (ii) a wound chamber model described by Lundgren and Lindhe (1970). The results showed (i) that the wound chamber method is well suited for studying leukocyte chemotactic activity elaborated by dental plaque (ii) that factors in dental plaque stimulate the emigration mainly of neutrophils (iii) that there is no increase in the amount of chemotactic factors/mg plaque with increasing age of the plaque. Data from the wound chamber experiments further revealed that the plaque filtrates tested do not markedly influence the permeability to plasmaproteins and water of granulation tissue vessels.