However, placing ligature around a tooth is known to cause dental plaque accumulation and oral mucosal ulceration, reproducibly inducing periodontitis-like lesions including tissue detachment and bone loss.27–29 Therefore, we adopted the ligature-induced periodontitis mouse model to investigate the effect of severe periodontitis on atherogenesis in ApoE−/− mice, as wild-type mice do not develop atherosclerosis under HFD. This evidence concerns the gene APOE and atherosclerosis.