Edentulism (missing teeth) and brain central nervous system (CNS) deafferentation: a narrative review

Abstract

Background and Objective: Edentulism is a major public health issue that poses plenty of systemic health ramifications. The absence of teeth impairs an individual’s ability to speak and alters their facial aesthetics negatively. Moreover, edentulism undermines the ability to adequately chew food, particularly those with firmer textures, which are often nutrient-dense fruits and vegetables. Nevertheless, the dental deafferentation (DD) that characterize tooth loss and its deleterious impact on the brain is a budding paradigm. The objective of this narrative review is to explore the effects of edentulism on the central nervous system (CNS) via the process of deafferentation. Methods: We reviewed the literature from 1985 to 2021 to identify all relevant studies published regardless of study design across PubMed. Studies in languages other than English were excluded. Key Content and Findings: The process of DD secondary to tooth loss eliminates several peripheral afferent neural inputs, which can cause central reorganization of the sensory and motor cortices. Adequate mastication with complete dentition reinforces such neural functional streams. As such, DD and the resulting, impaired mastication forces the brain to undergo neuroplastic changes, which are often accompanied by detrimental effects. When the DD impacts neural networks associated with the facial and vestibulocochlear nerves, taste and hearing deficits may result respectively. Cognitive decline may follow DD and edentulism—the impaired cerebral blood flow that follows suboptimal mastication, the poor, nutrient-sparse diets of edentulous individuals, and the chronic inflammation associated with periodontitis among edentulous individuals are the key mechanisms behind this link. The neural stresses imposed by DD and edentulism in excess can damage the brain to an extent enough to trigger Alzheimer’s disease (AD). Conclusions: The neural implications edentulism on the brain are vast, from sensory deficits to cognitive decline, extending far beyond facial aesthetics and ability to chew. The neural interconnectedness among the teeth, mastication, and the brain suggest novel interventions that can be taken to promote brain health and prevent the exacerbation of neurodegenerative disease.