There is currently no consensus among researchers on the optimal level of fluoride for human growth and health. As drinking water is not the sole source of fluoride for humans, and fluoride can be found in many food sources, this work aimed to determine the incidence and severity of dental fluorosis in Poland, in areas where a low fluoride content characterizes the drinking water, and to assess the impact of fluoride on the enamel composition and microstructure. The dental examination involved 696 patients (aged 15–25 years) who had since birth lived in areas where the fluoride concentration in drinking water did not exceed 0.25 mg/L. The severity of the condition was evaluated using the Dean’s Index. Both healthy teeth and teeth with varying degrees of fluorosis underwent laboratory tests designed to assess the total protein and fluoride content of the enamel. Protein amount was assessed spectrophotometrically while the level of fluoride ions was measured by DX-120 ion chromatography. The clinical study revealed 89 cases (12.8%) of dental fluorosis of varying severity. The enamel of teeth with mild and moderate fluorosis contained a significantly higher protein (p-value < 0.001 and 0.002, respectively) and fluoride level (p < 0.001) than those with no clinical signs of fluorosis. SEM images showed irregularities in the structure of the fluorotic enamel. An excessive fluoride level during amelogenesis leads to adverse changes in the chemical composition of tooth enamel and its structure. Moreover, dental fluorosis present in areas where drinking water is low in fluorides indicates a need to monitor the supply of fluoride from other possible sources, regardless of its content in the water.
*Full-text article online at https://www.mdpi.com/1660-4601/19/12/7153/htm
… The substantial increase in fluorosis observed in recent years is associated with the emergence of many additional, essential sources of fluoride, which influence the human body [39,49]. Some authors believe that the introduction of brushing with fluoride toothpaste on a widespread and daily basis was the main factor behind the increased prevalence of this disorder. The lack of adult supervision of children when brushing their teeth with fluoride toothpaste and the excessive use and even swallowing of such toothpaste continue to be risk factors for dental fluorosis, as documented in research [50,51]. The observations of Butera et al., are also interesting. They have shown that in the case of patients with composite dental restorations, a good solution is the daily use of a toothpaste containing Zn-carbonate hydroxyapatite .
The latest reports from North Columbia, which is a region with low fluoride content in the drinking water and fluoridates salt as part of the public health prophylactic program, concerning a three-year follow-up study in 8–12-year-old children, showed the dynamic post-eruptive nature of this dental fluorosis and a significant proportion of the teeth with more advanced fluorotic changes . The fact that no cases of severe fluorosis were recorded in this study indicates that the study population had not been exposed to high concentrations of fluoride during amelogenesis. Research conducted worldwide in areas with low fluoride content is consistent with the findings of the present study. In American studies carried out as part of the National Health and Nutrition Examination Survey (NHANES) 2015–2016 concerning 2098 children and adolescents, the fluoride concentration in water above the level of 0.7 mg/L was 25%, but the prevalence of dental fluorosis was 70%. In this study, higher plasma fluoride concentrations were associated with higher odds of dental fluorosis in females, while this association almost disappeared in males . In the presented research, we noticed the prevalence of fluorosis in females, which may suggest an influence of gender-specific hormonal and mineral metabolism.
The findings of this study revealed an increase in the occurrence and severity of fluorosis in people living in areas in which drinking water has a low fluoride ion content. Associating fluorosis exclusively with elevated levels of fluoride ions in drinking water is not justified nowadays, as there are many other potential sources of fluoride.
The availability of fluoride from other sources has increased significantly, and fluoride in drinking water is now recognized as just one component making up an individual’s total fluoride intake. Because of the widespread use of toothpaste and other dental health care products containing fluoride and the potential for fluoride exposure from several other sources, monitoring the total exposure to which we are subjected has become essential. As a future objective, it is necessary to add the alternatives to fluoride, to have a natural supply of hydroxyapatite and as to not aggravate the environmental factors. Many opportunities and challenges lie ahead in the implementation of new remineralization technology.
It is beneficial to remember the possibility to use toothpastes that do not contain fluoride. Instead, it is replaced with natural components such as herbs, which are characterized by anti-bacterial properties, as seen in e.g., bamboo salt . Other types of toothpaste include those which contain phosphorus compounds, calcium phosphate, functionalized ?-tricalcium phosphate, calcium glycerophosphate, cyclophosphates, calcium sucrose phosphate, zinc hydroxyapatite, or toothpastes with an acidic pH [71,72]. Recently, it has been shown that toothpaste with a potent penetration promoter, azone, and vitamin D3 may be helpful in the prevention of the common deficiencies of this vitamin. According to the authors, the aforementioned toothpaste did not contain fluoride compounds .