Subgingival spirochete and leukocyte counts as indicators of response to therapy

The aim of this study was to determine whether changes in probing attachment levels are related to subgingival spirochete or leukocyte counts in periodontal pockets. Following initial clinical recordings and therapy consisting of oral hygiene instruction and root debridement, the probing attachment levels of proximal sites of 120 single-rooted teeth in 7 patients were measured every 3 months for 12 months. The measurements of each site were subjected to regression analysis, which determined whether the site was deteriorating, improving, or non-changing. Subgingival washings were taken of 19 deteriorating, 22 improving, and 127 non-changing sites to determine the number and % of spirochetes and the number of leukocytes at each site. Improved probing attachment levels were associated with reduced numbers of spirochetes and leukocytes. However, the ranges of individual measurements of subgingival washing variables overlapped considerably between groups. Spirochete and leukocyte counts related better to the 12-month probing depths than to changes in probing attachment levels during the preceding 12 months. These findings suggest that none of the tested subgingival washing parameters are suitable indicators of changes in attachment levels on an individual site basis.