Fig. 1.

Suppression of oral microbial invasion and local inflammation by tooth extraction. a Bacterial colony formation in the culture of the liver and spleen cells from mice subjected to an experimental periodontitis model (PD). This formation was abrogated by tooth extraction (PD-Ext). Colony formation was not observed in the control (Ctrl) or tooth-extracted (Ext) group. Representative pictures of more than three independent experiments are shown. b Colony-forming units (CFUs) in aerobic (Aero) and anaerobic (Anero) cultures of liver and spleen cells from mice in Ctrl (n = 5), Ext (n = 4), PD (n = 4), or PD-Ext (n = 4) groups, pooled from two independent experiments. c 16S sequence analysis of tissue cultures, ligature (Oral), or fecal samples (Fecal) collected from a mouse in the PD group. The top fifteen frequently detected bacterial species in the aerobic liver culture are listed on the left and the sequence frequency (represented by the bottom bar) in each sample is shown. Representative data of more than three independent experiments is presented. d Quantitative RT-PCR analysis of inflammatory cytokines in the periodontal tissues collected from mice in the Ctrl, Ext, PD, or PD-Ext groups (n = 3). The data were obtained from duplicated experiments. All samples were collected at day 42. All data are shown as the mean ± s.e.m. Statistical analyses were performed using ANOVA with Tukey’s multiple-comparison test. *P < 0.05; **P < 0.01; ***P < 0.005; ND, not detected; NS, not significant