A rapid and simple method for counting crevicular polymorphonuclear leucocytes.

The techniques presently available for counting crevicular polymorphonuclear leucocytes (CPMNs) require special equipment and are only semi-quantitative. The present new and simple method is based on the property that Durapore strips have to harvest a maximum number of crevicular cells and to release them when shaken in a suitable buffer. Durapore strips were inserted into periodontal crevices or pockets, shaken in PBS and the liberated PMNs counted in a Neubauer chamber. The validity of the method was ascertained in 5 experiments. First, it was shown that 90% of the harvested cells were released from Durapore strips after being shaken in buffer. Second, decreasing numbers of CPMNs were found when performing sequential samplings. Third, when counting CPMNs before and after therapy, a significant decrease in the number of cells was found. Fourth, we could confirm that sites with bleeding on probing did contain a much higher number of CPMNs as compared to non-bleeding sites. Finally, our counting technique confirmed that deeper pockets contain a significantly higher number of CPMNs.