Mastication Influences Human Brain Anatomy

The purpose of this observational clinical study was to evaluate the relationship between brain anatomical and volumetric changes in white matter, grey matter, and cerebral cortex thickness with the number of functional occlusal pairs present in the mouth.

The number of functional occlusal pairs in 70 patients was counted and non-invasive brain analysis was performed using magnetic resonance imaging. The volume of grey matter, white matter, and thickness of the cortex in different areas of the brain were determined by SPM12 and CAT12 software. Multiple regression model corrected for multiple comparisons using FDR and Spearman correlation coefficient were calculated for statistical comparison.

A total of 70 (39 male, 31 female) were analysed, with an average number of occlusal pairs of 10.21 (3.99). According to the Spearman correlation coefficient, a lower number of occlusal pairs was related to a reduction in white matter (right external capsule and posterior limb of the internal capsule), a reduction in grey matter (right temporal superior and medial gyrus and left cerebellum crus 1) and a reduction in thickness of the cerebral cortex (rostral anterior cingulated cortex of the right hemisphere and areas in the right and left hemisphere, especially in the frontal cortex).

The number of occlusal pairs is related to the volume of white matter, grey matter, and thickness of the cerebral cortex in areas of the brain that are directly involved in the onset and progression of Alzheimer's disease and other dementias.