Tooth loss, periodontal infection and their relationship to cognitive impairment and other dementias: A review

Abstract

Our review study addresses the issue of tooth loss, which is caused by loss of masticatory function and its impact on cognitive functions, dementia, and Alzheimer's disease. Numerous studies have confirmed a positive correlation between premature tooth loss, reduction in masticatory function and significant cognitive decline observed through learning disabilities, including overcoming ordinary life problems to early and advanced forms of dementia. Reduced numbers of teeth in the main food processing area, i.e., loss of large molars, have been implicated as a possible cause of cognitive impairment. In research in this area, some groups of major etiopathogenetic causes of this issue have also been established. A significant etiopathogenetic cause of tooth loss is the disappearance of their mechanoreceptors in the periodontium, causing the disappearance of sensorimotor excitation via the cranial nerve V and the associated atrophic changes in the trigeminal brain nuclei and their branching in the Locus Coeruleus area. It may cause further neurodegenerative involvement in this area, one of the centers of the adrenergic system involved in cognitive function. Relatively well-studied factors are the lack of blood supply to the cerebral area during inadequate mastication caused by loss of molars and the consequent hypoxia of brain and nerve structures. In the research and development of Alzheimer's disease, there have been many recent references to the fact that the primary bacterium causing periodontitis, Porphyromonas gingivalis, can infect the neurons of the cranial nerve V ending close to the Locus Coeruleus and thus tau proteins, after tooth extractions, can spread to other subcortical nuclei in the brain. These findings are of great relevance to clinical practice in dentistry as we strive to prevent tooth loss in the distal compartment, which is made possible by the tremendous expansion of endodontic techniques and technologies to save de facto every tooth and its periodontium with the mechanoreceptors necessary to preserve sensorimotor nerve excitability and sensorimotor nerve networks. We uncompromisingly eliminate every periodontal infection in the subgingival region as part of our preventive-therapeutical procedures.