Specifically, APP-Tg mice with periodontitis induced by oral infection with P. gingivalis ATCC33277, showed greater deposition of Aβ40 and Aβ42 amyloid plaques in both the hippocampus and cortex and increased brain expression of TNF-α and IL-1β, compared with sham-infected APP-Tg mice. Here, TNF is linked to periodontitis.