Periodontal therapy: a novel non-drug-induced experimental model to study human inflammation

Background: Chronic periodontitis causes a low-grade systemic inflammatory response; its standard treatment, however, induces an acute inflammatory response. The aim of this study was to describe the systemic inflammatory reactions to an intensive periodontal treatment regimen. Methods: Fourteen otherwise healthy subjects suffering from severe chronic periodontitis were enrolled in a 1 month pilot single-blind trial. Intensive periodontal treatment, consisting of full-mouth subgingival root debridement delivered within a 6-h period, was performed. Periodontal parameters were recorded before and 1 month after completion of treatment. Blood samples were taken at baseline and 1, 3, 5, 7 and 30 days after treatment. Interleukin-1 receptor antagonist (IL-1Ra), Interleukin-6 (IL-6) and C-reactive protein (CRP) serum concentrations were determined by enzyme-linked immunosorbent assay (ELISA). Complete blood counts were also performed. Results: One day after treatment, mild neutrophilia and monocytosis (p < 0.05) and lymphopenia (p < 0.01) were accompanied by a sharp increase in inflammatory markers (IL-1Ra, IL-6, p < 0.01). A 10-fold increase in CRP (p < 0.001) was detected on day 1 and its kinetics followed a pattern of a classical acute phase response (significantly raised concentrations up to 1 week, p < 0.01). At 3-7 days after treatment, subjects presented also with a mild tendency towards a normocytic anaemic state (p < 0.01) and a degree of lympho-thrombocytosis (p < 0.05). The observed changes were similar to those expected following the well-characterized endotoxin-challenge model of inflammation. Conclusions: Intensive periodontal treatment produced an acute systemic inflammatory response of 1 week duration and might represent an alternative to classic endotoxin-challenge or drug-induced models to study acute inflammation in humans.