Relationship of Porphyromonas gingivalis and Alzheimer's disease: a systematic review of pre-clinical studies.

OBJECTIVES: This study aimed to analyze the following PICO question: Are animals infected with Porphyromonas gingivalis (P. gingivalis) or bacterial lipopolysaccharide (Pg-LPS) more affected by neurodegeneration, similar to the pathogenesis generated by Alzheimer's disease (AD), compared with non-infected animals? METHODS: Databases PubMed, Lilacs, SciELO, Science Direct, Scopus, Web of Science, and Cochrane were searched for pre-clinical in vivo studies in which mice were infected with P. gingivalis or received Pg-LPS, in order to assess the brain tissue and cognitive impairment. No limit for date or publication language was imposed and this study was registered at the International Prospective Register of Systematic Reviews (PROSPERO), with nine articles included. Syrcle's protocol was used to evaluate bias in the selected studies. RESULTS: Nine articles were included. Infection by P. gingivalis or the administration of Pg-LPS increased the production of the inflammatory mediators, TNF-α (tumor necrosis factor-alpha), IL-6 (interleukin-6), and IL-1ß (interleukin-1beta), augmented Aß (amyloid beta) production, and activated the complement system, causing inflammation, brain tissue degeneration, and cognitive impairment, consistent with the damage in AD. CONCLUSIONS: Infection by P. gingivalis and Pg-LPS administration appears to be in relation with the pathogenesis of AD by activating the complement cascade, increasing Aß production and augmenting pro-inflammatory cytokine expression, causing age-dependent brain inflammation, neuroinflammation, and neurodegeneration. CLINICAL RELEVANCE: Taking into account the importance of holistic treatment in the dental office, this study focuses on identifying highly prevalent oral diseases, such as periodontal disease, as risk factors for the aggravation of degenerative diseases in the elderly population.

Socio-demographic factors and oral health conditions in the elderly: a population-based study.

The aim of the present study was to analyze the relationship between oral health conditions and socio-demographic factors in an elderly population from Macaíba/RN (Brazil). A questionnaire was used to characterize the socio-demographic profiles and a clinical examination was performed to assess oral health conditions such as tooth decay, gum disease, use of dental prosthesis, need for dental prosthesis and soft tissue injuries. The technique of random sampling by conglomerates was used, taken from randomly selected census drafts, with a total sample of 441 individuals. The prevalence of edentulism, bleeding and dental calculus was 50.8%, 27.2% and 32%, respectively, excluding all sextants in 59% of the elderly. Data analysis was conducted using the chi-squared test with the level of significance set at 5%. Prior to association tests, the dependant variables were submitted to principal component analysis. Four factors were extracted to represent the oral health conditions of elderly individuals. A statistically significant association was found between the following variables: gender and the presence of a caregiver with gum disease; age, residence area, presence of a caregiver and household density with need for dental prosthesis; and household density with soft tissue injuries. Therefore, precarious oral health conditions were found among the elderly and associations were found between these conditions and the socio-demographic factors, particularly gender, age and residence area. The results obtained demonstrated the need for improved oral health conditions in the elderly. The study of these conditions, allied to socio-demographic factors, is important in terms of both dental care and public policy planning related to these individuals.