The pathogenesis of Alzheimer's disease (AD) remains an enigma and the fact that there are no adequate treatments for this disease means research remains an open field. There is a rising healthcare cost associated with the management of AD with an already stretched service provision. The newly formed World Dementia Council outlined key challenges of tackling dementia. One key priority is to examine the modifiable risk factors that influence the development of AD. A risk factor relationship between periodontal pathogens and periodontal disease and AD is suggested by improved memory following dental intervention. In addition, periodontitis is one of the most easily manageable risk factors for a number of conditions including cardio/cerebrovascular pathologies and diabetes, which are often co-morbid with ageing and AD. Our key findings linking periodontitis with AD include demonstration of the keystone periodontal pathogen Porphyromonas gingivalis and adverse effects of innate immune mediators on host's blood-brain barrier and mental health in mice models. Our research continues searching oral bacterial links with AD hallmark proteins such as amyloid-beta (Aβ) and abnormal tau protein in relation to the appearance of AD pathology whilst educating the public on reducing the incidence of periodontal disease may provide numerous health benefits in later life.