Masticatory Function and Corticomotor Plasticity Across the Lifespan: Implications for Older Adults—A Scoping Review

Background/Objectives: Mastication is a complex sensorimotor function involving coordination between the brainstem central pattern generator and supraspinal systems, particularly the primary motor cortex (M1). Evidence suggests a link between masticatory activity and corticomotor plasticity, but findings remain fragmented. This scoping review aimed to synthesise the human evidence on the relationships among mastication, tooth loss, dental rehabilitation, ageing, and corticomotor plasticity, with emphasis on M1 mechanisms. Methods: Following PRISMA-ScR guidelines, systematic searches were conducted in MEDLINE/PubMed, Scopus, and Web of Science using terms related to mastication, neuroplasticity, motor cortex, ageing, and rehabilitation. Eligible studies included human experimental, clinical, and observational research employing neuroimaging or neurophysiological methods. Data were extracted and synthesised using a Population–Concept–Context framework across eight conceptual domains. Results: Twenty-two heterogeneous studies (fMRI, TMS, EMG, psychophysical, histological) were included. Mastication consistently activated distributed sensorimotor networks, including M1 and the primary somatosensory cortex (S1). Peripheral sensory input and dental mechanoreception were linked to structural and functional adaptations. Corticomotor excitability was modulated by chewing, oral-motor learning, and rehabilitative interventions. Ageing was associated with altered but preserved cortical responsiveness. Associations between mastication and cognition were reported, though largely cross-sectional. Overall, findings suggested a relationship linking peripheral input, sensorimotor integration, and corticomotor plasticity, but methodological variability limited causal inference. Conclusions: Mastication is linked to modifiable corticomotor activity and supports experience-dependent neuroplasticity. However, the evidence remains largely associative and methodologically heterogeneous. Neural adaptations appear to be preserved with ageing but are influenced by systemic and environmental factors. Longitudinal, multimodal research is needed to clarify the mechanisms, causality, and clinical relevance, particularly in rehabilitation contexts.