This study aimed to investigate the impact of dental caries and tooth loss on oral health-related quality of life (OHRQoL) in socioeconomically disadvantaged people. A population-based, cross-sectional survey was conducted in 28 cities at social risk in Northeast Brazil. All permanent residents aged 12, 15–19, 35–44, and 65–74 years were eligible, and 3063 were included. Participants answered a questionnaire on socioeconomic status, beliefs, and behaviors. Trained local dentists performed oral clinical examinations during home visits. Caries and tooth loss were evaluated using the decayed, missing, and filled teeth (DMFT) index and OHRQoL was evaluated using the Oral Health Impact Profile-14 (OHIP-14). Poisson regression analysis was performed to assess the relationship between individual domains, OHIP-14 scores, dental caries, tooth loss, and socioeconomic/demographic characteristics. Mean DMFT (standard deviation) scores were 2.68 (4.01), 4.84 (4.30), 15.35 (7.26), and 26.72 (8.03) for groups aged 12, 15–19, 35–44, and 65–74 years, respectively. Most participants (70%) were partially edentulous and 13% were completely edentulous. Caries and tooth loss significantly increased with age and impacted OHRQoL. Physical pain (5.8%) and psychological discomfort (5.8%) were the most commonly reported on the OHIP-14. Untreated caries (prevalence ratio (PR), 1.54; 95% confidence interval (CI), 1.37–1.72) and edentulism (PR, 1.29; 95% CI, 1.08–1.53) had a significant negative impact on OHRQoL. Income, level of education, sex, age, and oral hygiene habits were also related to OHRQoL. There was a high prevalence of dental caries and edentulism in all age groups except 12-year-olds. OHRQoL was negatively impacted by these oral conditions across the lifespan, with a trend towards more negative scores and higher impact in older adults.

This chapter aims to present a scoping review of the association between exposure to fluoride and low intelligence quotient (IQ) scores in children. The mechanism of fluoride in reducing IQ is still a matter of debate. Rats affected by chronic fluorosis may have altered membrane lipids that could be a cause of a brain disorder. It is suggested that in humans, high fluoride in the water can affect children’s cognitive abilities and mental development. However, concentrations of fluoride in the drinking water to provoke chronic fluorosis in rats need to be 5 times higher when compared to similar doses for humans. Scientific evidence for the fluoride-low IQ relationship comes mostly from case-control studies with low levels of evidence and problems related to confidence in exposure to the risk factor and potential risk of bias. In addition to water fluoride, some studies try to relate this problem to other fluoride methods, such as salt fluoridation and the regular use of fluoride toothpaste. It can be concluded that there is a lack of consistent prospective studies on this topic to conclusively assess the association between exposure to fluoride and low IQ scores in children.