Fig. 1.

Representative PET images of Aβ and tau in HCs and AD-spectrum patients. Axial ¹¹C-PiB (Aβ) and ¹⁸F-PM-PBB3 (tau) PET images of individual participants. PET images were coregistered with the individual anatomical magnetic resonance images. Representative PET images were shown according to participant group, and good and poor oral condition, respectively. White arrowhead indicates tau PET tracer binding in the brainstem. Tau PET tracer retention was increased in the brainstem in a subset of AD-spectrum patients with poor oral parameters compared with HCs. AD, Alzheimer’s disease; BGI, biofilm–gingival interface; HCs, healthy controls; MMSE, Mini Mental State Examination; PET, positron emission tomography; SUVR, standard uptake value ratio.