Masticatory deficit and cognitive decline in humans: a critical and quantitative analysis of the scientific literature

Masticatory deficit and cognitive decline are serious health conditions that together have the potential to impair human health as a whole. Thus, the objective of our study was to conduct a bibliometric review of studies investigating the relationship between cognitive decline and masticatory dysfunction in humans in the twenty-first century. To this end, we used (BIBLIO) as a basis to develop a search key in the Web of Science-main collection database, in which we selected articles based on previously defined inclusion and exclusion criteria. We performed metric and content analyses of the selected studies. From this, we obtained 2,014 articles, of which 160 were selected. The first study was published in 2003, and the most cited authors were Gondo, Yasuyuki; Ikebe, Kazunori; Ishizaki, Tatsuro; Kabayama, Mai; Kamide, Kei; and Masui, Yukie, all with six published documents. Regarding citations, we found that the most cited authors were Desrosiers, Mark; Donegan, Sara Jean; Kryscio, Richard J.; Stein, Pamela Sparks; and Yepes, Juan F., all with 305 citations. The most frequently occurring keyword was "Dementia" with 113 occurrences, and the journal with the highest volume of citations was the Journal of Oral Rehabilitation, with 115 publications. The university with the highest volume of articles was the Tokyo Metropolitan Institute of Gerontology with 12 publications, and the country with the highest occurrence was Japan with 52 articles. In the content analysis, it was possible to retrieve that the most frequently performed study was a cross-sectional study, the most investigated masticatory deficit was tooth loss, and its diagnosis was mainly clinical. Cognitive decline was identified as the most common condition, and its diagnosis was made using the Mini-Mental State Examination test. The characteristics of the samples showed that most studies focused on the elderly population of both sexes and with heterogeneous sample sizes. In the analysis of the association between conditions, most of the selected studies assumed that there is an association between them. Thus, our study concluded that the association between masticatory deficit and cognitive decline is a growing area of interest worldwide and that it influences the stability and health prospects of the population.