Two teams from the University of Rutgers found that neglecting oral health may lead to a decline in cognitive abilities in the human mind due to brain damage.
Oral health provides a picture of human internal health and, in some cases, is an indicator of serious mental disorders, the study said.
These suspicions began in 2010 when the Indian dental newspaper published research saying oral diseases increased the risk of heart disease by 20 percent.
The studies focused on Chinese-American adults, including people as young as 60.
The sample was selected because minorities often do not receive adequate oral health care, said Shinky Dong, director of the Rutgers Institute of Health at the American University.
People from minorities are not receiving adequate oral health care, either because of language barriers or because of their economic and social situation, Dong said.
Initially, the researchers asked the participants questions and then conducted tests to measure mental and cognitive abilities.
Nearly half of the 2,700 respondents said they had experienced dental health-related symptoms, but only a quarter of those surveyed reported dry mouth.
The study found that people who were affected by oral health, suffered at a mental capacity level, later.